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Relatively high-protein or 'low-carb' energy-restricted diets for body weight loss and body weight maintenance?
Abstract
Background:
'Low-carb' diets have been suggested to be effective in body weight (BW) management. However, these diets are relatively high in protein as well.
Objective:
To unravel whether body-weight loss and weight-maintenance depends on the high-protein or the 'low-carb' component of the diet.
Design:
Body-weight (BW), fat mass (FM), blood- and urine-parameters of 132 participants (age=50 ± 12 yr; BW=107 ± 20 kg; BMI=37 ± 6 kg/m(2); FM=47.5 ± 11.9 kg) were compared after 3 and 12 months between four energy-restricted diets with 33% of energy requirement for the first 3 months, and 67% for the last 9 months: normal-protein normal-carbohydrate (NPNC), normal-protein low-carbohydrate (NPLC); high-protein normal-carbohydrate (HPNC), high-protein low-carbohydrate (HPLC); 24h N-analyses confirmed daily protein intakes for the normal-protein diets of 0.7 ± 0.1 and for the high-protein diets of 1.1 ± 0.2g/kg BW (p<0.01).
Results:
BW and FM decreased over 3 months (p<0.001): HP (-14.1 ± 4 kg; -11.9 ± 1.7 kg) vs. NP (-11.5 ± 4 kg; -9.3 ± 0.7 kg) (p<0.001); LC (-13.5 ± 4 kg; -11.0 ± 1.2 kg) vs. NC (-12.3 ± 3 kg; -10.3 ± 1.1 kg) (ns). Diet × time interaction showed HPLC (-14.7 ± 5 kg; -11.9 ± 1.6 kg) vs. HPNC (-13.8 ± 3 kg; -11.9 ± 1.8 kg) (ns); NPLC (-12.2 ± 4 kg; -10.0 ± 0.8 kg) vs. NPNC (-10.7 ± 4 kg; -8.6 ± 0.7 kg) (ns); HPLC vs. NPLC (p<0.001); HPNC vs. NPNC (p<0.001). Decreases over 12 months (p<0.001) showed HP (-12.8 ± 4 kg; -9.1 ± 0.8 kg) vs. NP (-8.9 ± 3 kg; -7.7 ± 0.6 kg) (p<0.001); LC (-10.6 ± 4 kg; -8.3 ± 0.7 kg) vs. NC (11.1 ± 3 kg; 9.3 ± 0.7 kg) (ns). Diet × time interaction showed HPLC (-11.6 ± 5 kg ; -8.2 ± 0.7 kg) vs. HPNC (-14.1 ± 4 kg; -10.0 ± 0.9 kg) (ns); NPNC (-8.2 ± 3 kg; -6.7 ± 0.6 kg) vs. NPLC (-9.7 ± 3 kg; -8.5 ± 0.7 kg) (ns); HPLC vs. NPLC (p<0.01); HPNC vs. NPNC (p<0.01). HPNC vs. all other diets reduced diastolic blood pressure more. Relationships between changes in BW, FM, FFM or metabolic parameters and energy percentage of fat in the diet were not statistically significant. Metabolic profile and fat-free-mass were improved following weight-loss.
Conclusion:
Body-weight loss and weight-maintenance depends on the high-protein, but not on the 'low-carb' component of the diet, while it is unrelated to the concomitant fat-content of the diet.
... One article followed the crossover design (Cheskin et al. 2008a) and 26 articles presented parallel RCT. Fifteen (Appel et al. 2011;Cheskin et al. 2008a;Daubenmier et al. 2016;Foster et al. 2003;Foster et al. 2010;Layman et al. 2009;Nackers et al. 2018;Papandonatos et al. 2015;Pascale et al. 1995;Pearl et al. 2018;Peterson et al. 2014;Trepanowski et al. 2017;Tsai et al. 2015;Villareal et al. 2011;Wadden et al. 1998) of the 27 included studies were conducted in the USA and they were followed by studies carried out in Australia (n=3) (Carter, Clifton, and Keogh 2019;Purcell et al. 2014;Seimon et al. 2020), Netherlands (n=3) (Skender et al. 1996;Snel et al. 2011;Soenen et al. 2012), Finland (n=2) (Fogelholm, Kukkonen-Harjula, and Oja 1999;Pekkarinen and Mustajoki 1997), Sweden (n=2) (Lantz et al. 2003;Torgerson et al. 1999), Norway (n=1) (Sundfor, Tonstad, and Svendsen 2018) and United Kingdom (n=1) (Cooper et al. 2010). ...
... The selected studies included from 27 (Snel et al. 2011) to 3,906 participants (Papandonatos et al. 2015), and mean follow-up duration was 72 weeksfollow-up time ranged from 24 to 240 weeks. Six studies only included women (Fogelholm, Kukkonen-J o u r n a l P r e -p r o o f Harjula, and Oja 1999;Nackers et al. 2018;Peterson et al. 2014;Seimon et al. 2020;Wadden et al. 1998;Cooper et al. 2010), 19 assessed men and women together, and two studies did not provide such information (Pascale et al. 1995;Soenen et al. 2012). On average, participants age varied from 41.9 + 9.07 (Cooper et al. 2010) to 69.7 + 2.7 years (Villareal et al. 2011); baseline BMI ranged from 32.4 + 0.55 (Layman et al. 2009) to 46.0 + 5.6 kg/m² (Pekkarinen and Mustajoki 1997). ...
... Weight loss intervention groups were guided by dietitians in 13 studies (Carter, Clifton, and Keogh 2019;Cheskin et al. 2008b;Fogelholm, Kukkonen-Harjula, and Oja 1999;Foster et al. 2003;Foster et al. 2010;Layman et al. 2009;Purcell et al. 2014;Seimon et al. 2020;Skender et al. 1996;Soenen et al. 2012;Sundfor, Tonstad, and Svendsen 2018;Trepanowski et al. 2017;Villareal et al. 2011) and by other health professionals in 6 studies (Appel et al. 2011;Nackers et al. 2018;Pascale et al. 1995;Pekkarinen and Mustajoki 1997;Peterson et al. 2014;Snel et al. 2011); groups were guided by both, a dietitian and other professionals, in 4 of the studies (Daubenmier et al. 2016;Cooper et al. 2010;Lantz et al. 2003;Papandonatos et al. 2015). There was a great diversity of weight loss intervention strategies, including diet (n=8) (Carter, Clifton, and Keogh 2019;Foster et al. 2003;Seimon et al. 2020;Snel et al. 2011;Soenen et al. 2012;Torgerson et al. 1999;Trepanowski et al. 2018;Tsai et al. 2015), diet combined with behavioral treatment (n=8) (Cheskin et al. 2008a;Lantz et al. 2003;Pearl et al. 2018;Sundfor, Tonstad, and Svendsen 2018;Skender et al. 1996;Villareal et al. 2011;Wadden et al. 1998;Cooper et al. 2010), diet combined with behavioral treatment and exercising (n=11) (Cooper et al. 2010;Daubenmier et al. 2016;Foster et al. 2010;Nackers et al. 2018;Papandonatos et al. 2015;Pascale et al. 1995;Pekkarinen and Mustajoki 1997;Peterson et al. 2014;Skender et al. 1996;Villareal et al. 2011;Wadden et al. 1998), diet combined with exercising (n=4) (Layman et al. 2009;Fogelholm, Kukkonen-Harjula, and J o u r n a l P r e -p r o o f Oja 1999;Purcell et al. 2014;Snel et al. 2011), and behavioral treatment combined with exercising (n=2) (Appel et al. 2011;Pekkarinen and Mustajoki 1997). ...
Background & Aims
The purpose of this systematic review was to analyze the effects of lifestyle interventions on long-term weight maintenance of weight loss. In addition, we seek to address which period is most susceptible to weight regain; and what is the time required for following-up weight maintenance after the intervention. Methods: Articles published up to August 2020 were identified using the Medline (PubMed), Embase, Web of Science, CENTRAL and Scopus. Results: After the selection process, 27 clinical trials involving 7,236 individuals were included. The results showed that around 36 weeks after the end of the intervention, weight variation variation reduces, and a sign of continuous weight gain begin to occur with some patients (n = 208209) presenting even a completely regain of the lost weight before one year (∼40-48 weeks). However, some strategies used during the weight loss intervention and maintenance period may impact the amount and when the weight regain happens, like intervention type;, intervention duration;, presence of dietitian on the care team;, and maintenance period with counseling by a health professional at least once a month. Conclusion: This systematic review and meta-analysis showed that lifestyle interventions remained effective in maintaining the mean weight (5% lower than baseline weight) after weight loss interventions were over. However, weight regain started 36 weeks after intervention conclusion. And, it turns out, some strategies used during the weight loss intervention and maintenance period may impact the amount and when the weight regain happens. Obesity complexity and chronicity should be considered, therefore constant and lifelong monitoring and support are important.
... High protein vs. low-protein diets applied in long-term randomized controlled trials on body-weight loss and subsequent body-weight maintenance show a larger body-weight loss, including a larger fat oxidation, loss of fat mass, and sparing of fat free body mass, sustained satiety and energy expenditure [158][159][160][161][162][163]. Such results are partly different from studies comparing relatively high-protein with mediumprotein diets [125,163]. ...
... High protein vs. low-protein diets applied in long-term randomized controlled trials on body-weight loss and subsequent body-weight maintenance show a larger body-weight loss, including a larger fat oxidation, loss of fat mass, and sparing of fat free body mass, sustained satiety and energy expenditure [158][159][160][161][162][163]. Such results are partly different from studies comparing relatively high-protein with mediumprotein diets [125,163]. In the latter studies, a medium-protein diet usually implies a protein intake at the level of the minimal requirement (0.8 g/kg body weight daily) which is sufficient for body weight loss, fat loss, and body-weight maintenance [101,125,163]. ...
... Such results are partly different from studies comparing relatively high-protein with mediumprotein diets [125,163]. In the latter studies, a medium-protein diet usually implies a protein intake at the level of the minimal requirement (0.8 g/kg body weight daily) which is sufficient for body weight loss, fat loss, and body-weight maintenance [101,125,163]. However, an additional increase of protein intake, e.g. a protein intake of 1.2 g/kg can be effective in maintaining a larger amount of FFM, and sustaining energy expenditure through sparing of FFM [101,118]. ...
... However, the optimal macronutrient composition for successful BW loss remains unresolved [3][4][5]. Whilst a higher protein (HP) intake is hypothesised to promote BW loss [6][7][8][9], it is often confounded by the accompanying lower carbohydrate (CHO) content [10]. To provide substantiation for protein-induced BW loss, the European Food Safety Authority [11] deemed it necessary to untangle the effect of dietary protein from CHO. ...
... The sample size was determined based on the difference in BW loss between two independent groups. Based on similar BW data from Soenen's study [10], 32 participants were required in each intervention group to detect a minimum difference of 2.8 kg in mean BW loss with 80% power and 95% significance level. Therefore, with 4 intervention groups in this study, a total of 128 participants were required to be enrolled in the study. ...
... Contrary to our hypothesis, we did not observe significant differences in BW and FM loss between the HP and NP LED pdr . Although several meta-analyses have demonstrated the effect of HP diets on BW, FM and FFM loss [16,[51][52][53], supporting findings from Soenen and colleagues [10], it is notable that the difference in BW, FM and FFM loss between HP and NP were modest in the metaanalysis. For instance, Vogtschmidt et al. [53] highlighted that HP promoted BW loss by 0.64 kg and FM loss by 0.55 kg, but had no significant effect on FFM, when compared to NP diets in randomised controlled trials of 4-156 weeks, aiming for BW loss and maintenance. ...
Both higher protein (HP) and lower carbohydrate (LC) diets may promote satiety and enhance body weight (BW) loss. This study investigated whether HP can promote these outcomes independent of carbohydrate (CHO) content. 121 women with obesity (BW: 95.1 ± 13.0 kg, BMI: 35.4 ± 3.9 kg/m2) were randomised to either HP (1.2 g/kg BW) or normal protein (NP, 0.8 g/kg BW) diets, in combination with either LC (28 en%) or normal CHO (NC, 40 en%) diets. A low-energy diet partial diet replacement (LEDpdr) regime was used for 8 weeks, where participants consumed fixed-energy meal replacements plus one ad libitum meal daily. Four-day dietary records showed that daily energy intake (EI) was similar between groups (p = 0.744), but the difference in protein and CHO between groups was lower than expected. Following multiple imputation (completion rate 77%), decrease in mean BW, fat mass (FM) and fat-free mass (FFM) at Week 8 in all was 7.5 ± 0.7 kg (p < 0.001), 5.7 ± 0.5 kg (p < 0.001), and 1.4 ± 0.7 kg (p = 0.054) respectively, but with no significant difference between diet groups. LC (CHO×Week, p < 0.05), but not HP, significantly promoted postprandial satiety during a preload challenge. Improvements in blood biomarkers were unrelated to LEDpdr macronutrient composition. In conclusion, HP did not promote satiety and BW loss compared to NP LEDpdr, irrespective of CHO content.
... The PREVIEW study hypothesized that a relatively high-protein, low-glycemic-index (GI) diet (hereafter HP) would support weight-loss maintenance to a greater extent and concurrently reduce insulin resistance. This study compared HP with a moderate-protein, moderate-GI diet (hereafter MP) for body-weight reduction and concurrent prevention of T2D (4,(8)(9)(10)(11)(12)(13)(14)(15). However, despite the differences in dietary instructions, both the HP and MP groups achieved considerable and similar weight-loss maintenance, reduced HOMA-IR, and reduced glycated hemoglobin (HbA1c), a measure of average blood glucose concentration (4). ...
... The observation of increases in P Est and P Rep (g/kg and En%) being associated with a decrease in BMI is in line with previous observations, and has been explained by dietary P inducing sustained satiety, energy expenditure, and sparing body FFM despite weight reduction, thus preventing weight cycling (10)(11)(12)(13)(14)(15). However, the decrease in BMI may be associated with not only the observed increases in P Est and P Rep , but also the decrease in nonprotein intake. ...
... Owing to the lack of biomarkers, we were not able to distinguish the individual contributions of the other macronutrients (21,42). A previous study, uncoupling high P and low CHO intake, showed that weight-loss maintenance was primarily due to an increase in dietary P, and not to a reduction of CHO intake (12). ...
Background
Observed associations of high-protein diets with changes in insulin resistance are inconclusive.
Objectives
We aimed to assess associations of changes in both reported and estimated protein (PRep; PEst) and energy intake (EIRep; EIEst) with changes in HOMA-IR, glycated hemoglobin (HbA1c), and BMI (in kg/m2), in 1822 decreasing to 833 adults (week 156) with overweight and prediabetes, during the 3-y PREVIEW (PREVention of diabetes through lifestyle intervention and population studies In Europe and around the World) study on weight-loss maintenance. Eating behavior and measurement errors (MEs) of dietary intake were assessed. Thus, observational post hoc analyses were applied.
Methods
Associations of changes in EIEst, EIRep, PEst, and PRep with changes in HOMA-IR, HbA1c, and BMI were determined by linear mixed-model analysis in 2 arms [high-protein-low-glycemic-index (GI) diet and moderate-protein-moderate-GI diet] of the PREVIEW study. EIEst was derived from energy requirement: total energy expenditure = basal metabolic rate × physical activity level; PEst from urinary nitrogen, and urea. MEs were calculated as [(EIEst − EIRep)/EIEst] × 100% and [(PRep − PEst)/PEst] × 100%. Eating behavior was determined using the Three Factor Eating Questionnaire, examining cognitive dietary restraint, disinhibition, and hunger.
Results
Increases in PEst and PRep and decreases in EIEst and EIRep were associated with decreases in BMI, but not independently with decreases in HOMA-IR. Increases in PEst and PRep were associated with decreases in HbA1c. PRep and EIRep showed larger changes and stronger associations than PEst and EIEst. Mean ± SD MEs of EIRep and PRep were 38% ± 9% and 14% ± 4%, respectively; ME changes in EIRep and En% PRep were positively associated with changes in BMI and cognitive dietary restraint and inversely with disinhibition and hunger.
Conclusions
During weight-loss maintenance in adults with prediabetes, increase in protein intake and decrease in energy intake were not associated with decrease in HOMA-IR beyond associations with decrease in BMI. Increases in PEst and PRep were associated with decrease in HbA1c.
This trial was registered at clinicaltrials.gov as NCT01777893.
... Parabens and bisphenols both show lipophilic properties due to their positive values (1.65-3.56) for the log of the octanol-water partition coefficient (K ow ), and have been widely detected in human adipose tissue (Soenen et al., 2012;Harris and Benedict, 1918;van der Meer et al., 2019). The lipophilic property of phthalates increases with the length of their alcohol chain and thus their molecular weight, making HMW-phthalates (molecular weight: ≥250 g/mol) more prone to be stored in adipose tissue (log(K ow ): 4.73 to 8.83) than LMW-phthalates (molecular weight: < 250 g/mol; log(K ow ): 1.61 to 4.45). ...
... Subjects were enrolled in the Lifestyle, OverWeight, Energy Restriction (LOWER) study (clinicaltrials.gov, NCT00862953), an open label, randomized treatment intervention of which details of the study design and eligibility criteria have been previously reported (Soenen et al., 2012). In short, adults with a body mass index (BMI) above 27 kg/m 2 were randomized to one of four energy-restricted diet groups differing in protein and/or carbohydrate content: normal-protein normal-carbohydrate (NPNC), normal-protein low-carbohydrate (NPLC), high-protein normal-carbohydrate (HPNC), and high-protein low-carbohydrate (HPLC). ...
... Extensive information on anthropometric measurements are reported elsewhere (Soenen et al., 2012). In short, waist circumference, weight and body composition were available for baseline and follow-up. ...
The link between exposure to endocrine disrupting chemicals (EDCs) and the rapid increase in prevalence of obesity has recently been suggested. However, the magnitude and health impact of EDC exposure in at-risk populations remain largely unclear. In this study, we investigated the effect of a dietary intervention driven reduction in adipose tissue on the magnitude of urinary EDC exposure and mobilization, and whether higher EDC exposure leads to impaired weight loss in obese individuals. In this post-hoc analysis of the Lifestyle, OverWeight, Energy Restriction (LOWER) study from the Netherlands, 218 subjects were included. Five parabens, three bisphenols and thirteen metabolites of eight phthalates were measured in 24-h urine using LC-MS/MS, before and after three-months of a calory-restricted weight reduction intervention program. Associations between adiposity-related traits and EDCs were tested using multivariable linear regression and linear mixed effects models. A multiple testing correction based on the false discovery rate (FDR) was applied. After the 3-month intervention, urinary paraben and bisphenol excretions remained similar. Excretions of mono-butyl phthalates and most high-molecular-weight phthalates decreased, whereas mono-ethyl phthalate increased (all FDR<0.05). A reduction in adipose tissue was not associated with higher urinary EDC excretions. Higher baseline EDC excretions were associated with higher post-intervention body-mass index (methyl-, propylparaben), waist circumference (propylparaben, mono-n-butyl phthalate, mono-benzyl phthalate), and body fat percentage (mono-ethyl phthalate, mono-benzyl phthalate). Associations between parabens and body-mass index, and mono-benzyl phthalate and waist circumference and body fat percentage remained after multiple testing correction (all FDR<0.05). In a study of obese participants, we observed a reduction in most phthalates after a weight reduction intervention. A reduction in adipose tissue may not lead to mobilization and successively to higher urinary EDC excretions. Higher baseline paraben and phthalate exposures were associated with reduced weight loss, suggesting obesogenic properties.
... According to Soenen et al. (2012) [77], it was found that the relatively high protein intake highlights the success of the so-called "low-carbohydrate" diet, which is usually high in protein. Reduced carbohydrate intake had no effect on decreasing body weight and fat mass during energy restriction, while increasing daily absolute protein promoted body weight loss while reducing fat mass during the weight loss phase. ...
... According to Soenen et al. (2012) [77], it was found that the relatively high protein intake highlights the success of the so-called "low-carbohydrate" diet, which is usually high in protein. Reduced carbohydrate intake had no effect on decreasing body weight and fat mass during energy restriction, while increasing daily absolute protein promoted body weight loss while reducing fat mass during the weight loss phase. ...
Featured Application
Nutritional Profiling for subsequent dietary supplements/nutraceuticals development and formulation as well as by-products valorification.
Abstract
In recent years, the scientific community has made significant progress in understanding nutrition, leading consumers to shift their preferences away from animal-based protein products and towards natural, plant-based protein sources. This study aimed to determine the nutritional value, in vitro cytotoxicity and antioxidant activity for different sources of high protein content products (pea, yeast, almond, spirulina and Pleurotus spp.) with potential usage as raw materials for dietary supplements, especially since these products do not benefit from stricter regulation requirements regarding their actual health benefits. The characterization of raw materials consisted in evaluation of their nutritional profile (by addressing moisture content, crude protein content, extractable fat, ash, carbohydrates) and microbial contamination (TAMC, TYMC, Enterobacteriaceae and β-glucuronidase positive Escherichia coli), total content of free amino acids, soluble proteins, phenols and flavonoids, as well as antioxidant activity through chemical assays. We used 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay and lactate dehydrogenase (LDH) release to evaluate the potential cytotoxicity of selected raw materials. Results obtained indicate high percentages of proteins for the pea powder (77.96%) and Spirulina powder (64.79%), Pleurotus spp. flour had strong antioxidant activity, while the highest contamination values were registered for Pleurotus spp. powder (4.6 × 10⁵ CFU/g or 5.66 log CFU/g). Cytotoxicity results demonstrate that tested ingredients have an impact on the metabolic activity of cells, affecting cellular integrity and provoking leakage of DNA at several concentrations. While plant-based protein supplementation may appear to be a promising solution to balance our busy lives, there are several advantages and disadvantages associated with them, including issues related to their absorption rate, bioavailability, cytotoxicity and actual nutritional benefits.
... High protein intake with restriction of energy from carbohydrates has received extensive attention in recent years. Evidence has revealed the health benefits of a high-protein diet for weight loss and management of cardiometabolic risks, including improving glycemic control in people with diabetes mellitus, reducing blood pressure, and maintaining metabolic parameters (3,4). Conversely, long-term observational studies have shown that diets high in protein, are associated with an unfavorable risk of type 2 diabetes, hypertension, and metabolic syndrome (5,6). ...
... A constant highprotein diet has been found to increase glucagon and insulin stimulation, probably decreasing insulin sensitivity (7)(8)(9). These associations between protein consumption and health outcomes remain inconsistent in nutrition research since the findings of observational and experimental studies are conflicting (3)(4)(5)(6)(7)(8)(9)(10)(11). However, consuming enough protein while reducing carbohydrate intake, especially caloric-dense carbohydrates, remains a constant recommendation in many countries like the US, China, and England, for human growth, development, and health (12)(13)(14)(15). ...
Background
Dietary protein and carbohydrate intake and health outcomes have received extensive attention in recent years. However, the nutritional context in which these associations occur is less studied.
Objectives
We aimed to examine the dietary context associating protein-to-carbohydrate ratio and all-cause mortality in US adults.
Methods
Data from 17,814 adults enrolled in the 2007–2014 NHANES was analyzed. Information on mortality was obtained from the US mortality registry updated in December 2015. Diet quality was assessed using the Healthy Eating Index (HEI) and Total Nutrients Index (TNI). ANCOVA was used to test the mean differences in HEI and TNI scores across %E P:C quintiles. Linear regression examined the association of HEI and TNI with %E P:C. Cox proportional hazards regression evaluated the association between %E P:C and all-cause mortality. A restricted cubic spline examined the non-linear relationship between %E P:C and death.
Results
Low %E P:C was associated with lower HEI and TNI scores while higher %E P:C was associated with healthier HEI and TNI scores. HEI and TNI were positively associated with %E P:C (β = 0.22, 95% CI: 0.19–0.25, and β = 0.16, 95% CI: 0.14–0.18), respectively. Low %E P:C was associated with an increased risk of death from all-cause. The higher HRs (95% CIs) of all-cause mortality were 1.97(1.46–2.65), and 7.35 (2.57–21.03) in the second quintile for the age-sex-ethnicity model, and the fully adjusted model, respectively. There was a significant reverse U-shape relationship between %E P:C and all-cause mortality with P, non-linearity < 0.001.
Conclusion
This study indicates that a low %E P:C that gives emphasis to unhealthy foods increases the risk of death. Hence, it would be useful to consider the complete diet associated with protein intake when making dietary recommendations for populations.
... Oh et al. 41 indicated that the values of <10% (or 20-50 g/day), <26% (or 130 g/day), 26-44% and ≥45% of this macronutrient are used to define very low-, low-, moderate-and high-carbohydrate diets, respectively. Soenen et al. 42 observed that a low-carb-based diet had no effect on decrease body-weight and fat mass. However, this effect can be reversed when is combined with a high-protein treatment, helping to establish body-weight loss and weightmaintenance 42,43 . ...
... Soenen et al. 42 observed that a low-carb-based diet had no effect on decrease body-weight and fat mass. However, this effect can be reversed when is combined with a high-protein treatment, helping to establish body-weight loss and weightmaintenance 42,43 . A low carbohydrate diet has common short-term side-effects including constipation, fatigue, halitosis, headache, thirst, polyuria, rash and chest pain, among others 44 , while thar long-term disadvantages are high cholesterol level, accelerate the progression of pre-existing kidney disease and increased urinary calcium excretion 45 . ...
Introduction: In the last years, confusing or misleading use of the term called miracle or magic diets, using to weight loss treatment, has increased, along with several classification of them.
Objectives: The purpose of this narrative review is to discuss miracle slimming diets and proposal new term and new classification for these diets.
Methods: A narrative review up to September 2021 was carried out in the PubMed, Google Scholar, and Web of Knowledge. Furthermore, this strategy was complemented with a comprehensive search of the ‘grey’ literature [7] based in four different searching strategies: i) grey literature databases, ii) customized Google search engines, iii) targeted websites, and iv) consultation with contact experts.
Results: Our proposal is to use the new concept called hazardous slimming diets defined as diets that propose rapid weight loss (> 1 kg/week), to be performed effortlessly, without the super-vision of a medical/nutritional professional, excessive energy restrictions and/or exclusion from the diet of food or nutrients for the body. Furthermore, the development of a new algorithm reflected as is possible to classify the diet as non-effective, hazardous and effective diet.
Conclusions: Our review could help to classify and develop a new terminology about the miracle slimming diets focusing in the knowledge to guarantee the quality in the treatments for weight loss.
... Reduction in dietary carbohydrate content is often compensated for by other macronutrients such as dietary protein. Soenen et al. [33] showed that "high-protein" component is more important than "low-carbohydrate" component on weight loss and subsequent weight maintenance in humans. Dietary protein has a greater positive effect on thermogenesis [7], satiety [6] and lean body mass [34][35][36] compared to dietary carbohydrates or fat. ...
... Dietary protein has a greater positive effect on thermogenesis [7], satiety [6] and lean body mass [34][35][36] compared to dietary carbohydrates or fat. Evidence shows that higher protein intake might be beneficial for weight management [8,9,33]. However, our study showed no significant benefits for health and changes in body composition when protein intake was increased from 20% to 35% kcal. ...
Caloric restriction (CR) is of key importance in combating obesity and its associated diseases. We aimed to examine effects of dietary macronutrient distribution on weight loss and metabolic health in obese mice exposed to CR. Male C57BL/6J mice underwent diet-induced obesity for 18 weeks. Thereafter mice were exposed to a 6-week CR for up to 40% on either low-fat diet (LFD; 20, 60, 20% kcal from protein, carbohydrate, fat), low-carb diet (LCD; 20, 20, 60% kcal, respectively) or high-pro diet (HPD; 35, 35, 30% kcal, respectively) (n = 16 each). Ten mice on the obesogenic diet served as age-matched controls. Body composition was evaluated by tissue dissections. Glucose tolerance, bloods lipids and energy metabolism were measured. CR-induced weight loss was similar for LFD and LCD while HPD was associated with a greater weight loss than LCD. The diet groups did not differ from obese controls in hindlimb muscle mass, but showed a substantial decrease in body fat without differences between them. Glucose tolerance and blood total cholesterol were weight-loss dependent and mostly improved in LFD and HPD groups during CR. Blood triacylglycerol was lowered only in LCD group compared to obese controls. Thus, CR rather than macronutrient distribution in the diet plays the major role for improvements in body composition and glucose control in obese mice. Low-carbohydrate-high-fat diet more successfully reduces triacylglycerol but not cholesterol levels compared to isocaloric high-carbohydrate-low-fat weight loss diets.
... The importance of proteins in both diets is noteworthy, since, as far as a comparison of the effectiveness of the HFLC and HCLF diets in terms of the body mass reduction and body fat index is concerned, the examined participants often consume different amounts of proteins (the protein intake in HFLC diets is often higher) (Volek et al., 2004;Forsythe et al., 2008;Samaha et al., 2003). The increased number of proteins in a hypocaloric diet positively impacts the maintenance of fat-free body mass, which might have influenced the obtained results of the research in terms of the comparison of the effectiveness of diets based on different fats and carbohydrates (Soenen et al., 2012). Hence, it is significant to keep a similar protein intake in diets based on different proportions of other macronutrients to assess their impact on body composition. ...
... Hence, it is significant to keep a similar protein intake in diets based on different proportions of other macronutrients to assess their impact on body composition. Soenen et al. (2012) studied the importance of the impact of protein intake in a diet on body fat reduction. They proved that persons eating a highprotein diet obtained a higher body mass reduction when compared to those following a low-carbohydrate diet with a smaller number of proteins. ...
Low‐fat, high‐carb (LFHC) and low‐carb, high‐fat (LCHF) diets change body composition as a consequence of the reduction of body fat of overweight persons. The aim of this study is the assessment of the impact of LFHC and LCHF diets on body composition of men of a healthy body mass who do strength sports while maintaining the appropriate calorific value in a diet and protein intake. The research involved 55 men aged 19–35, with an average BMI of 24.01 ± 1.17 (min. 20.1, max. 26.1). The participants were divided into two groups following two interventional diets: high‐fat diet or high‐carb diet, for 12 weeks. The body composition of the participants was measured using bioimpedance. After the 12‐week‐long experiment based on the low‐carbohydrate diet, a significant body mass reduction of 1.5% was observed. In the group, following the LFHC diet, the parameters did not significantly change. In the group following LCHF diet, the body fat reduction of 8.6% from 14 (6.7–19.8) kg to 12.7 (3.9–19.2) was reported (p = 0.01) (in the absolute value of 1.2 kg). However, also in the LFHC group, the body fat mass was significantly reduced, that is, by 1.5% (p = 0.01) (by 0.4 kg). Nevertheless, it is worth emphasizing that despite significant changes within the groups, these changes were not statistically significant between the groups. Diets with different carbohydrate and fat intake and the energy value covering the energy needs of men training strength sports have similar impact on changes in body composition. Low‐fat, high‐carb (LFHC) and low‐carb, high‐fat (LCHF) diets change body composition as a consequence of the reduction of body fat of overweight persons. Despite significant changes within the groups, these changes were not statistically significant between the groups. Diets with different carbohydrate and fat intake and the energy value covering the energy needs of men training strength sports have similar impact on changes in body composition.
... Out of 313 subjects of the LOWER study [19], 22 non-bariatric control subjects were selected for comparison of fasting parameters with those of the bariatric subjects. In brief, the LOWER study recruited subjects ranging in BMI from 27 to 60 kg/m 2 for a randomised study with four parallel energy-restricted intervention diets differing in protein and/or carbohydrate content. ...
... Eleven of these subjects had undergone CC prior to the MMTT study (RYGB-CC) and, therefore, out of the remaining 22 subjects eleven subjects with their gallbladder in situ (RYGB) were randomly selected. A total of 22 control subjects from the LOWER study [19], with participants from the same region and with the same ethnicity, were selected to provide baseline control values, matched on age, BMI and gender. The subject characteristics are presented in Table 1. ...
Bile acids (BA) act as detergents in intestinal fat absorption and as modulators of metabolic processes via activation of receptors such as FXR and TGR5. Elevated plasma BA as well as increased intestinal BA signalling to promote GLP-1 release have been implicated in beneficial health effects of Roux-en-Y gastric bypass surgery (RYGB). Whether BA also contribute to the postprandial hypoglycaemia that is frequently observed post-RYGB is unknown.
Plasma BA, fibroblast growth factor 19 (FGF19), 7α-hydroxy-4-cholesten-3-one (C4), GLP-1, insulin and glucose levels were determined during 3.5 h mixed-meal tolerance tests (MMTT) in subjects after RYGB, either with (RYGB, n = 11) or without a functioning gallbladder due to cholecystectomy (RYGB-CC, n = 11). Basal values were compared to those of age, BMI and sex-matched obese controls without RYGB (n = 22).
Fasting BA as well as FGF19 levels were elevated in RYGB and RYGB-CC subjects compared to non-bariatric controls, without significant differences between RYGB and RYGB-CC. Postprandial hypoglycaemia was observed in 8/11 RYGB-CC and only in 3/11 RYGB. Subjects who developed hypoglycaemia showed higher postprandial BA levels coinciding with augmented GLP-1 and insulin responses during the MMTT. The nadir of plasma glucose concentrations after meals showed a negative relationship with postprandial BA peaks. Plasma C4 was lower during MMTT in subjects experiencing hypoglycaemia, indicating lower hepatic BA synthesis. Computer simulations revealed that altered intestinal transit underlies the occurrence of exaggerated postprandial BA responses in hypoglycaemic subjects.
Altered BA kinetics upon ingestion of a meal, as frequently observed in RYGB-CC subjects, appear to contribute to postprandial hypoglycaemia by stimulating intestinal GLP-1 release.
... A large body of literature suggests the diet effectively induces fat loss in both untrained (10-12,40,41,42, 57,61,71,76,85) and trained populations (29, 63,68,87,92,93). The studies reveal that the KD promotes equal or superior fat mass loss compared to control diets. ...
... Even if no caloric limit is set, participants reduce caloric intake on their own initiative (3,25). Furthermore, participants report that their hunger is reduced in multiple ketogenic studies (24,25,41,42,48,51,53,55,60,72,76). The combination of lowered hunger and spontaneous caloric restriction may be a useful tool for competitors who are aiming at reducing their caloric intake. ...
In the past decades, the ketogenic diet has received scientific interest as a diet which may be beneficial for athletes. We summarize the ketogenic literature and give competitive bodybuilders and physique athletes advice on whether the diet and ketone supplements are suitable for off-season and in-season use.
The diet is effective for fat loss and has a strong hunger-reducing effect. Current evidence suggests it is suboptimal for bulking and gaining lean mass. Upon starting the diet, negative side effects should be expected and prevented by increasing intake of electrolytes, fiber, and water. Exogenous ketones are currently not recommended.
... Patients with a BMI of over 27 were referred from a weight loss clinic. 47 Chemical analysis was performed using LC-MS/MS and baseline measurements prior to the diet were taken. For bisphenols, it is unclear whether this was only the parent compound or included gluconated or sulfonated forms, which represent the metabolites and are present at higher concentrations. ...
Calorie‐restricted diets cause weight loss and can drive type 2 diabetes remission. However, many patients struggle to achieve clinically relevant weight loss, and the reasons are not well understood. Chemical exposure is associated with obesity and type 2 diabetes development, and some evidence from preclinical experiments suggests it can limit the clinical benefits of calorie restriction. We systematically reviewed the evidence for the effects of environmental chemical exposure on mass loss and glycemic control during diet‐induced weight management in humans (PROSPERO: CRD42022339993). Of 222 unique citations, only six papers directly examined this question. Only one targeted people with type 2 diabetes. One linked phthalates and parabens, but not bisphenols, with slower fat loss. Two showed per‐ and polyfluoroalkyl substances were not associated with mass loss, but with faster subsequent mass regain. One linked impaired adiposity improvements with air pollutants. Two papers reported weight loss‐induced elevation in plasma organochlorines associated with altered glycemic control. The risk of bias largely arose from the potential for deviation from the intended diet, and statistics and reporting. The role of chemical exposure in impeding the effectiveness of weight management programs needs to be better understood to provide suitable support to people living with obesity and type 2 diabetes.
... The meta-analysis by Clifton et al. (62) used a broad definition of low carbohydrate, HPD and it is not clear on whether the higher protein or the lower carbohydrate was the 'driving' factor for weight management benefits. In a novel 12 month weight loss and maintenance study, Soenen et al. (64) showed that raising dietary protein is much more relevant than lowering CHO with respect to weight and fat loss. The design of this study compared four isoenergetic diets: HPD low carbohydrate; HPD lower fat; SPD low carbohydrate and SPD lower fat. ...
The review aims to explore the potential benefit and risk of high-protein diets (HPD) regarding the comorbidity of sarcopoenia and CVD in the setting of cardiac rehabilitation (CR). CR is standard care for individuals who have experienced a cardiac event, but the current practice of predominantly aerobic exercise, a lower-fat diet and weight loss poorly addresses the issue of sarcopoenia. HPD, especially when combined with resistance exercise (RE), may be valuable adjuncts to current CR practice and benefit both muscle and cardiovascular health. Meta-analyses and randomised controlled trials of HPD and CVD risk show beneficial but variable effects regarding weight loss, the lipid profile, insulin resistance and lean body mass in those living with or high risk of CVD. Meta-analyses of prospective cohort studies on hard CVD endpoints favour lower- and plant-protein diets over higher animal protein, but the evidence is inconsistent. HPD augment the strength and muscle gaining benefits of RE in older populations, but there are no published data in those living with CVD providing promising opportunities for CR research. HPD raise concern regarding renal and bone health, the microbiome, branched chain amino acids and environmental sustainability and findings suggest that plant-based HPD may confer ecological and overall health advantages compared to animal-based HPD. However, incorporating RE with HPD might alleviate certain health risks. In conclusion, a largely plant-based HPD is deemed favourable for CR when combined with RE, but further research regarding efficacy and safety in CR populations is needed.
... The prevalence of overweight/obesity is rapidly increasing at an alarming rate in most parts of the world and is estimated to affect about 20% of the adult population by 2030 [1]. Complex mechanisms have been shown to lead to obesity; however, it is mainly the result of an imbalance between energy intake and energy expenditure [2,3]. Several studies on the obesogenic and metabolic effects of dietary macronutrients have shown that dietary macronutrient composition can play a pivotal role in energy metabolism and body weight adjustment [4]. ...
Background
Different dietary protein sources are supposed to have various effects on metabolic responses and arterial stiffness in the postprandial period. This study aims to assess the postprandial effects of dietary protein sources, including animal-based protein (AP) and plant-based protein (PP), as part of a high-protein breakfast on appetite response, energy metabolism, and arterial stiffness in overweight and obese men.
Methods
This acute randomized crossover clinical trial will be conducted at the Persian study research center at Imam Reza Hospital, affiliated with the Mashhad University of Medical Sciences, located in the northeast of Iran. Forty-six healthy overweight, and obese men aged 18–60 years will be enrolled based on the eligibility criteria. The subjects will complete two interventions (high-protein AP and PP meals) with 1 week washout period. The primary outcome will be the acute effect of the two test meals on appetite response, energy metabolism parameters, including resting metabolism rate (RMR), diet-induced thermogenesis (DIT), and substrate oxidation (SO), and arterial stiffness indices, including pulse wave velocity (PWV) and pulse wave analysis (PWA). The secondary outcomes include changes in lipemia, glycemia, and insulinemia.
Discussion
The findings of this study will provide novel insight regarding the acute effects of different protein sources on energy metabolism, appetite, and arterial stiffness as a significant cardiovascular disease (CVD) risk factor. It will help dieticians develop effective and efficient meal plans to improve weight reduction and maintenance in overweight/obese individuals.
Trial registration
Iranian Registry of Clinical Trials; code: IRCT20211230053570N1; registered on February 10, 2022
... [6] In terms of comparing the efficacy of diet depending on various carbohydrates and fats, the increased protein in a hypocaloric diet can positively effects fat-free body mass maintenance. [7] The same study reported that individuals who followed high protein diet lost more body mass than those who followed a low-carb diet with less proteins. It is important to highlight and answer the question of which diet is best for losing body mass and having the least negative effects on muscle mass. ...
High carbohydrate diet was incorporated into typical Iraqi food and was given for 35 days to 27 healthy volunteers (males and females). The biochemical parameters including glucose, insulin, urea, creatinine, lipid profile, cortisol and HOMA-IR were analyzed before and after the experiment period. The results depicted significant rise in levels of triglycerides, total cholesterol, low density lipoprotein, and very low-density lipoprotein and significant decline in high density lipoprotein due to high carbohydrate diet (P≤0.05). Furthermore, the plasma insulin, fasting blood sugar, cortisol, HOMA-IR, creatinine, and urea were significantly increased. These findings show that high carbohydrate diets alter insulin, triglycerides, and high density lipoprotein cholesterol levels, which have been linked to an increase in the prevalence of coronary artery disease.
... [6] In terms of comparing the efficacy of diet depending on various carbohydrates and fats, the increased protein in a hypocaloric diet can positively effects fat-free body mass maintenance. [7] The same study reported that individuals who followed high protein diet lost more body mass than those who followed a low-carb diet with less proteins. It is important to highlight and answer the question of which diet is best for losing body mass and having the least negative effects on muscle mass. ...
High carbohydrate diet was incorporated into typical Iraqi food and was given for 35 days to 27 healthy volunteers (males and females). The biochemical parameters including glucose, insulin, urea, creatinine, lipid profile, cortisol and HOMA-IR were analyzed before and after the experiment period. The results depicted significant rise in levels of triglycerides, total cholesterol, low density lipoprotein, and very low-density lipoprotein and significant decline in high density lipoprotein due to high carbohydrate diet (P≤0.05). Furthermore, the plasma insulin, fasting blood sugar, cortisol, HOMA-IR, creatinine, and urea were significantly increased. These findings show that high carbohydrate diets alter insulin, triglycerides, and high density lipoprotein cholesterol levels, which have been linked to an increase in the prevalence of coronary artery disease.
... Soenen et al. [5] demonstrated that a high-protein diet can help with body-weight loss and weight maintenance. This also resulted in a larger reduction of body weight and fat mass, and thereafter, since they promote a sustained level of satiety, sustained energy expenditure, sparing of fat-free mass, and increased fat oxidation [6,7]. ...
Recently, personalized meals and customized food design by means of 3D printing technology have been considered over traditional food manufacturing methods. This study examined the effects of different proteins (soy, cricket, and egg albumin protein) in two concentrations (3% and 5%) on rheological, textural, and 3D printing characteristics. The textural and microstructural properties of different formulations were evaluated and compared. The addition of soy and cricket protein induced an increase in yield stress (τ₀), storage modulus (G′), and loss modulus (G″) while egg albumin protein decreased these parameters. The textural analysis (back extrusion and force of extrusion) demonstrated the relationship between increasing the amount of protein in the formula with an improvement in consistency and index of viscosity. These values showed a straight correlation with the printability of fortified formulas. 3D printing of the different formulas revealed that soy and cricket proteins allow the targeting of complex geometry with multilayers.
... On the other hand, since dietary fats do not stimulate insulin secretion, high fat isocaloric diets reduce insulin secretion promoting fat loss from adipose tissue, turning free-FA available for use by metabolically active tissues [21]. Finally, dietary proteins are known to positively influence fat-free mass during weight loss [22]; thus, high protein diets offer benefits in terms of energy expenditure and body composition. ...
This study aimed to observe if quinoa could produce a benefit on postprandial glycemia that would result in less progression to type 2 diabetes (T2D). A cross-over design pilot clinical study with a nutritional intervention for 8 weeks was performed: 4 weeks on a regular diet (RD) and 4 weeks on a quinoa diet (QD). Nine subjects aged ≥65 years with prediabetes were monitored during the first 4 weeks of RD with daily dietary records and FreeStyle Libre®. Subsequently, participants started the QD, where quinoa and 100% quinoa-based products replaced foods rich in complex carbohydrates that they had consumed in the first 4 weeks of RD. The glycemic measurements recorded by the sensors were considered as functions of time, and the effects of nutrients consumed at the intended time period were analyzed by means of a function-on-scalar regression (fosr) model. With QD participants, decreased body weight (−1.6 kg, p = 0.008), BMI (−0.6 kg/m2 p = 0.004) and waist circumference (−1.5 cm, p = 0.015) were observed. Nutrients intake changed during QD, namely, decreased carbohydrates (p = 0.004) and increased lipids (p = 0.004) and some amino acids (p < 0.05). The fosr model showed a reduction in postprandial glycemia in QD despite intrapersonal differences thanks to the joint action of different nutrients and the suppression of others consumed on a regular diet. We conclude that in an old age and high T2D-risk population, a diet rich in quinoa reduces postprandial glycemia and could be a promising T2D-preventive strategy.
... The human trials presented support the 316 use of a KD for a reduction in nervous system sensitivity, however a LCD also reports 317 benefits. It is unclear from the current research what level of carbohydrate restriction is 318 required, whether the effect increases proportionately with carbohydrate reduction, or what 319 diet duration length is required for favourable impacts on nervous system sensitisation. 320 Further research using larger participant numbers is required to help answer these questions 321 which are relevant for clinical application. ...
Dietary restriction of carbohydrate has been demonstrated to be beneficial for nervous system dysfunction in animal models and may be beneficial for human chronic pain. The purpose of this review is to assess the impact of a low-carbohydrate/ketogenic diet on the adult nervous system function and inflammatory biomarkers to inform nutritional research for chronic pain. An electronic data base search was carried out in May 2021. Publications were screened for prospective research with dietary carbohydrate intake <130g/day and duration of ≥2 weeks. Studies were categorised into those reporting adult neurological outcomes to be extracted for analysis and those reporting other adult research outcomes Both groups were screened again for reported inflammatory biomarkers. From 1548 studies there were 847 studies included. Sixty-four reported neurological outcomes with 83% showing improvement. Five hundred and twenty-three studies had a different research focus (metabolic n=394, sport/performance n=51, cancer n=33, general n=30, neurological with non-neuro outcomes n=12, or gastrointestinal n=4). The second screen identified 63 studies reporting on inflammatory biomarkers with 71% reporting a reduction in inflammation. The overall results suggest a favourable outcome on the nervous system and inflammatory biomarkers from a reduction in dietary carbohydrates. Both nervous system sensitisation and inflammation occur in chronic pain and the results from this review indicate it may be improved by low-carbohydrate nutritional therapy. More clinical trials within this population are required to build on the few human trials that have been done.
... Low carbohydrate diets compared with control diets have been suggested to be relatively more effective in body weight management. However, the benefits of a low carbohydrate diet can be rather attributed to the relatively high protein content, but not the relatively lower carbohydrate content (45,46). In a recent study with athletes, different approaches (high vs. low fat) but similar protein intakes resulted in a similar change of body composition (mean loss in body fat was 1.4 kg) (32). ...
Consuming low glycemic carbohydrates leads to an increased muscle fat utilization and preservation of intramuscular glycogen, which is associated with improved flexibility to metabolize either carbohydrates or fats during endurance exercise. The purpose of this trial was to investigate the effect of a 4-week high fat low carbohydrate (HFLC-G: ≥65% high glycemic carbohydrates per day; n = 9) vs. high carbohydrate low glycemic (LGI-G: ≥65% low glycemic carbohydrates daily; n = 10) or high glycemic (HGI-G: ≥65% fat, ≤ 50 g carbohydrates daily; n = 9) diet on fat and carbohydrate metabolism at rest and during exercise in 28 male athletes. Changes in metabolic parameters under resting conditions and during cycle ergometry (submaximal and with incremental workload) from pre- to post-intervention were determined by lactate diagnostics and measurements of the respiratory exchange ratio (RER). Additionally, body composition and perceptual responses to the diets [visual analog scale (VAS)] were measured. A significance level of α = 0.05 was considered. HFLC-G was associated with markedly decreased lactate concentrations during the submaximal (−0.553 ± 0.783 mmol/l, p = 0.067) and incremental cycle test [−5.00 ± 5.71 (mmol/l) × min; p = 0.030] and reduced RER values at rest (−0.058 ± 0.108; p = 0.146) during the submaximal (−0.078 ± 0.046; p = 0.001) and incremental cycle test (−1.64 ± 0.700 RER × minutes; p < 0.001). In the HFLC-G, fat mass (p < 0.001) decreased. In LGI-G lactate, concentrations decreased in the incremental cycle test [−6.56 ± 6.65 (mmol/l) × min; p = 0.012]. In the LGI-G, fat mass (p < 0.01) and VAS values decreased, indicating improved levels of gastrointestinal conditions and perception of effort during training. The main findings in the HGI-G were increased RER (0.047 ± 0.076; p = 0.117) and lactate concentrations (0.170 ± 0.206 mmol/l, p = 0.038) at rest. Although the impact on fat oxidation in the LGI-G was not as pronounced as following the HFLC diet, the adaptations in the LGI-G were consistent with an improved metabolic flexibility and additional benefits regarding exercise performance in male athletes.
... Consequently, the demand for effective diets has also increased. A variety of these has been reviewed in studies [2][3][4][5][6]. Two dietary strategies have become increasingly popular in recent years: the time-restricted feeding diet (TRF) and the macronutrient-based diet (MBD) with continuous energy restriction (CER). ...
The number of people suffering from being overweight or obese has risen steadily in recent years. Consequently, new forms of nutrition and diets were developed as potential solutions. In the last years, the time-restricted feeding and continuous energy restriction via macronutrient-based diets were increasingly popular. Both diets were exclusively studied separately. A comparison of the two diets for people with a high body mass index despite regular physical activity has not yet been studied in detail. Therefore, this study aimed to compare the effects of these two diets on body composition and adherence. For this study, a total of 42 subjects (m = 21, f = 21) with a BMI above 25 were recruited from a local fitness gym. After a two-week familiarisation period, one of the two diets was followed over 14 weeks. Dietary behaviour was monitored throughout the period with a food diary. The primary measurement parameters were body weight, lean body mass, fat mass, body mass index, and waist and hip circumference. In addition, adherence was assessed and calculated by food diary and questionnaire. In total, the data of 35 participants (m = 14, f = 21) were analysed. Significant reductions in body weight, fat mass, body mass index, and waist and hip circumference were observed in both groups (p < 0.05). No significant change could be observed in lean body mass in either category. No group and gender differences were detected in any of the primary parameters. For the secondary parameters, a significantly higher adherence was observed in the time-restricted feeding group (p < 0.05). In addition, it can be assumed that an adherence of 60–70% cannot lead to positive changes in body composition. In conclusion, there were no differences between the two diets on the primary parameters. However, it seemed that time-restricted feeding can be better implemented in everyday life, and an adherence of more than 70% is required for both diets to prove effective.
... Dysbiosis may also affect the production of metabolites in the colon, contributing to changes in gastrointestinal and host health . Because high-fiber, high-protein diets are effective in obesity management (Liu et al., 2003;Weigle et al., 2005;Soenen et al., 2012;Bermudez Sanchez et al., 2020), their influence on fecal characteristics, microbiota, and metabolites are important and were the focus of the current study. Barleybased β-glucans, beet pulp, short-chain fructooligosaccharides (scFOS), cellulose, and other fibers are known to reduce caloric density and nutrient digestibility and increase stool output (Fahey et al., 1990;Donadelli and Aldrich, 2019) responses that were observed in this study. ...
Obesity and estrogen reduction are known to impact the gut microbiota and gut microbial-derived metabolites in some species, but limited information is available in dogs. The aim of this study was to determine the effects of dietary macronutrient profile on apparent total tract macronutrient digestibility, fecal microbiota, and fecal metabolites of adult female dogs after spay surgery. Twenty-eight adult intact female beagles (age: 3.02 ± 0.71 yr, BW: 10.28 ± 0.77 kg; BCS: 4.98 ± 0.57) were used. After a 5-wk baseline phase (wk 0), 24 dogs were spayed and randomly allotted to one of three experimental diets (n=8/group): 1) control (CO) containing moderate protein and fiber (COSP), 2) high-protein, high-fiber (HPHF), or 3) high-protein, high-fiber plus omega-3 and medium-chain fatty acids (HPHFO). Four dogs were sham-operated and fed CO (COSH). All dogs were fed to maintain BW for 12 wk after spay, then allowed to consume twice that amount for 12 wk. Fecal samples were collected at wk 0, 12, and 24 for digestibility, microbiota, and metabolite analysis. All data were analyzed using repeated measures and linear Mixed Models procedure of SAS 9.4, with results reported as change from baseline. Apparent organic matter and energy digestibilities had greater decreases in HPHF and HPHFO than COSH and COSP. Increases in fecal acetate, total short-chain fatty acids, and secondary bile acids were greater and decreases in primary bile acids were greater in HPHF and HPHFO. Principal coordinates analysis of weighted UniFrac distances revealed that HPHF and HPHFO clustered together and separately from COSH and COSP at wk 12 and 24, with relative abundances of Faecalibacterium, Romboutsia, and Fusobacterium increasing to a greater extent and Catenibacterium, Bifidobacterium, Prevotella 9, Eubacterium, and Megamonas decreasing to a greater extent in HPHF or HPHFO. Our results suggest that high-protein, high-fiber diets alter nutrient and energy digestibilities, fecal metabolite concentrations, and fecal gut microbiota, but spay surgery had minor effects. Future research is needed to investigate how food intake, nutrient profile, and changes in hormone production influence gut microbiota and metabolites of dogs individually and how this knowledge may be used to manage spayed pets.
... Although the aetiology of obesity is complex, obesity has been believed to be due to energy intake (i.e. through diet) exceeding energy expenditure (i.e. through physical activity) (Elagizi et al., 2018). As such, improvements in body composition have focused on either energy intake or energy expenditure, or both (Elagizi et al., 2018;Soenen et al., 2012). In this regard, the most used and clinically recommended diets to improve or maintain an ideal body composition have been found to be high-carbohydrate, low-fat, energy deficit diets (Avenell et al., 2004;Foster et al., 2003). ...
Overweight and obesity are both a risk factor for developing and exacerbating type 2 diabetes (T2D). While the most common diet used to treat overweight and obesity focus on high-carbohydrate, low-fat, energy deficit diets, recently, low-carbohydrate, high-fat diets (LCHFD) have become popular in targeting obesity. This proof-of-concept study attempted to determine if an LCHFD could improve body composition variables, or if a concurrent treatment of LCHFD and physical activity would create an interference effect in individuals with T2D. Overweight and obese with T2D (n = 39) were assigned into either a 16-week combined physical activity and LCHFD group (ConG), LCHFD-only group (DieG) or control group (NonG). No statistically significant (p > 0.01) changes were found in body mass in the ConG (2.0%, F = 0.039, P = 0.846) and DieG (2.5%, F = 0.188, P = 0.669); for body mass index in the ConG (2.2%, F = 0.046, P = 0.832) and DieG (2.3%, F = 0.098, P = 0.758.); and waist-to-hip ratio in the ConG (0%, F = 0.002, P = 0.968) and DieG (0%, F = 0.023, P = 0.882). However, clinically significant changes were observed in HbA1c in the ConG male group (23% decrease); percentage body fat for the ConG (16.7%, F = 1.682, P = 0.208, g = 0.534) and DieG (13.0%, F = 0.638, P = 0435, g = 0.361); for waist circumferences in the ConG (5.4%, F = 0.686, P = 0.416, g = 0.341) and DieG (6.3%, F = 1.327, P = 0.264, g = 0.520); and for hip circumference in the ConG (5.8%, F = 0.993, P = 0.329, g = 0.410) and DieG (7.0%, F = 2.668, P = 0.119, g = 0.737). Results indicate that moderate clinically significant changes in body composition are achievable with LCHFD and/or daily walking in obese adults living with T2D. However, more robust research is required to determine the effects of LCHFD, with or without concurrent physical activity, on obesity and other diabetic complication markers.
... Significant differences in body weight loss over 3 months have also been reported while contrasting high-protein diets with regular protein diets. 25,33,34 We observed reduced TC and TG and systolic and diastolic BP levels on both diets, but these reductions were significantly higher in the high-protein group. High-protein diets have been shown to reduce the metabolic profile parameters after 3 months of energy restriction due to a comparatively higher protein content, which encourages a sustained level of satiety, sustainable energy intake, and increased fat oxidation. ...
Aims
The intermediate‐term effects of dietary protein on cardiometabolic risk factors in overweight and obese patients with heart failure and diabetes mellitus are unknown. We compared the effect of two calorie‐restricted diets on cardiometabolic risk factors in this population.
Methods and results
In this randomized controlled study, 76 overweight and obese (mean weight, 107.8 ± 20.8 kg) patients aged 57.7 ± 9.7 years, 72.4% male, were randomized to a high‐protein (30% protein, 40% carbohydrates, and 30% fat) or standard‐protein diet (15% protein, 55% carbohydrates, and 30% fat) for 3 months. Reductions in weight and cardiometabolic risks were evaluated at 3 months. Both diets were equally effective in reducing weight (3.6 vs. 2.9 kg) and waist circumference (1.9 vs. 1.3 cm), but the high‐protein diet decreased to a greater extent glycosylated haemoglobin levels (0.7% vs. 0.1%, P = 0.002), cholesterol (16.8 vs. 0.9 mg/dL, P = 0.031), and triglyceride (25.7 vs. 5.7 mg/dL, P = 0.032), when compared with the standard‐protein diet. The high‐protein diet also significantly improved both systolic and diastolic blood pressure than the standard‐protein diet (P < 0.001 and P = 0.040, respectively).
Conclusions
Both energy‐restricted diets reduced weight and visceral fat. However, the high‐protein diet resulted in greater reductions in cardiometabolic risks relative to a standard‐protein diet. These results suggest that a high‐protein diet may be more effective in reducing cardiometabolic risk in this population, but further trials of longer duration are needed.
... Compliance for protein intake, assessed by urinary biomarkers, showed differences up to 52 weeks, but MP had a mean protein intake of greater than 0.8 g/kg daily, which may be sufficiently high to promote body weight maintenance. [34][35][36][37][38] Post hoc analyses showed a difference in 3-year weight-loss maintenance between participants with a protein intake of <0.8 versus ≥0.8 g/kg daily, which confirmed a role of protein in weightloss maintenance. Adverse effects of a higher protein intake were not observed or reported, although fewer participants achieved normoglycaemia in HP than in MP at 3 years. ...
Aim:
To compare the impact of two long-term weight-maintenance diets, a high protein (HP) and low glycaemic index (GI) diet versus a moderate protein (MP) and moderate GI diet, combined with either high intensity (HI) or moderate intensity physical activity (PA), on the incidence of type 2 diabetes (T2D) after rapid weight loss.
Materials and methods:
A 3-year multicentre randomized trial in eight countries using a 2 x 2 diet-by-PA factorial design was conducted. Eight-week weight reduction was followed by a 3-year randomized weight-maintenance phase. In total, 2326 adults (age 25-70 years, body mass index ≥ 25 kg/m2 ) with prediabetes were enrolled. The primary endpoint was 3-year incidence of T2D analysed by diet treatment. Secondary outcomes included glucose, insulin, HbA1c and body weight.
Results:
The total number of T2D cases was 62 and the cumulative incidence rate was 3.1%, with no significant differences between the two diets, PA or their combination. T2D incidence was similar across intervention centres, irrespective of attrition. Significantly fewer participants achieved normoglycaemia in the HP compared with the MP group (P < .0001). At 3 years, normoglycaemia was lowest in HP-HI (11.9%) compared with the other three groups (20.0%-21.0%, P < .05). There were no group differences in body weight change (-11% after 8-week weight reduction; -5% after 3-year weight maintenance) or in other secondary outcomes.
Conclusions:
Three-year incidence of T2D was much lower than predicted and did not differ between diets, PA or their combination. Maintaining the target intakes of protein and GI over 3 years was difficult, but the overall protocol combining weight loss, healthy eating and PA was successful in markedly reducing the risk of T2D. This is an important clinically relevant outcome.
... In the present study, no effects on BP were found comparing the two protein intervention groups. However, studies reporting effects of dietary protein on the regulation of blood pressure are conflicting [32,33], possibly due to the type of protein, whether it originates from plants or animals, or due to a specific amino acid composition. In the context of the amino acid composition, sulfur-containing amino acids like cysteine or methionine may raise blood pressure, while amino acids involved in gluconeogenesis may have lowering effects on blood pressure [34]. ...
An unfavorable lipid profile and being overweight are known mediators in the development of cardiovascular disease (CVD) risk. The effect of diet, particularly high in protein, remains under discussion. Therefore, this study examines the effects of a high-protein (HP) diet on cardiometabolic health and vascular function (i.e., endothelial function, arterial stiffness, and retinal microvascular structure), and the possible association with plasma endocannabinoids and endocannabinoid-related compounds in overweight participants. Thirty-eight participants (64.5 ± 5.9 (mean ± SD) years; body mass index (BMI) 28.9 ± 4.0 kg/m2) were measured for 48 h in a respiration chamber after body-weight maintenance for approximately 34 months following weight reduction. Diets with either a HP (n = 20) or moderate protein (MP; n = 18) content (25%/45%/30% vs. 15%/55%/30% protein/carbohydrate/fat) were provided in energy balance. Validated markers for cardiometabolic health (i.e., office blood pressure (BP) and serum lipoprotein concentrations) and vascular function (i.e., brachial artery flow-mediated vasodilation, pulse wave analysis and velocity, and retinal microvascular calibers) were measured before and after those 48 h. Additionally, 24 h ambulatory BP, plasma anandamide (AEA), 2-arachidonoylglycerol (2-AG), oleoylethanolamide (OEA), palmitoylethanolamide (PEA), and pregnenolone (PREG) were analyzed throughout the day. Office and ambulatory BP, serum lipoprotein concentrations, and vascular function markers were not different between the groups. Only heart rate (HR) was higher in the HP group. HR was positively associated with OEA, while OEA and PEA were also positively associated with total cholesterol (TC) and low-density lipoprotein (LDL) cholesterol concentrations. Vascular function markers were not associated with endocannabinoids (or endocannabinoid-related substances). In conclusion, the HP diet did not affect cardiometabolic health and vascular function in overweight participants after completing a weight-loss intervention. Furthermore, our data indicate a possible association between OEA and PEA with TC and LDL cholesterol.
Seaweeds can be found in either marine or brackish water and have the potential to be bioactive. Seaweeds are important ecological, biological, and regenerative components of the maritime environment. Because of their high concentration of polysaccharides and phytochemicals, they have sparked a lot of interest in the domains of cosmetics, biomass for fuels, and as a source material for nanoparticle synthesis. Phytochemicals found in seaweeds aid in the conversion of metal ions to nanoparticles, which can easily overcome the tumor micro-environment barrier and cause damage in cancer cells. In addition, nanotechnology-based medicine has a promising therapeutic effect in cancer treatment. Functionalized nanoparticles improve the therapeutic effects of anticancer drugs while also delivering them to the tumor site over time. Metal nanoparticles have sparked a lot of attention in the scientific community for their use in biomedical nanotechnology. Drug-loaded metal nanoparticles were more hazardous to cancer cells than bare anticancer drugs.
The purpose of this study was to compare the effects of quinoa versus multigrain on glycemia and lipid metabolism among individuals with impaired glucose tolerance (IGT). A total of 207...
Introdução: A obesidade é um problema de saúde pública e vem aumentando de forma exponencial. Objetivo: Destacar a importância do trabalho multidisciplinar e discutir a utilização de uma técnica de execução que respeite o ordenamento das ações articulares das cinturas – escapular e pélvica envolvidas nos movimentos nos exercícios resistidos. Métodos: Um homem com 41 anos, obeso, com índice de massa corporal (IMC) de 42,58 kg/m2 e circunferência de cintura (CC) compatíveis para o alto risco de desenvolvimento de doenças cardiometabólicas foi submetido a um programa de intervenção multidisciplinar. Resultados: O indivíduo que participou do programa multidisciplinar supervisionado obteve melhorias consideráveis nos parâmetros de composição corporal, circunferências e razão cintura e estatura (RCE) e do perfil bioquímico pré e pós intervenção. Conclusão: O trabalho multidisciplinar é fundamental para melhoria da composição corporal, da CC e RCE e do perfil bioquímico. Além disso, critérios para padronização de uma técnica de execução que respeite a anatomia e a funcionalidade articular das cinturas escapulares e pélvica, assim como, a origem, a inserção e as ações musculares para obter um efetivo direcionamento da força deveriam ser objeto de discussão em pesquisas futuras. Palavras-chave: Síndrome metabólica; obesidade; exercício físico; estilo de vida.
Background
The Western diet, especially beverages and high processed food products, is high in sugars which are associated with the development of obesity and diabetes. The reduction of refined carbohydrates including free and added sugars improves glycemic control in individuals with diabetes, but the data regarding effects in subjects without diabetes are limited.
Objective
This study aimed to evaluate the effects of reducing free sugar intake on 24-h glucose profiles and glycemic variability using continuous glucose monitoring (CGM).
Methods
In the randomized controlled study, 21 normal weight and overweight/obese subjects (BMI 18–40 kg/m ² ) without diabetes were assigned to a 4-week reduced-sugar (RS) diet or control diet after a 2-week baseline phase. During the baseline phase, all participants were advised not to change their habitual diet. During the intervention phase, RS participants were asked to avoid added sugar and white flour products, whereas participants of the control group were requested to proceed their habitual diet. Anthropometric parameters and HbA1c were assessed before and at the end of the intervention phase. Interstitial glucose was measured using continuous glucose monitoring (CGM), and the food intake was documented by dietary records for 14 consecutive days during the baseline phase and for the first 14 consecutive days during the intervention phase. Mean 24-h glucose as well as intra- and inter-day indices of glucose variability, i.e., standard deviation (SD) around the sensor glucose level, coefficient of variation in percent (CV), mean amplitude of glucose excursions (MAGE), continuous overlapping net glycemic action (CONGA), and mean absolute glucose (MAG), were calculated for the baseline and intervention phases.
Results
During the intervention, the RS group decreased the daily intake of sugar (i.e., −22.4 ± 20.2 g, −3.28 ± 3.61 EN %), total carbohydrates (−6.22 ± 6.92 EN %), and total energy intake (−216 ± 108 kcal) and increased the protein intake (+2.51 ± 1.56 EN %) compared to the baseline values, whereby this intervention-induced dietary changes differed from the control group. The RS group slightly reduced body weight (−1.58 ± 1.33 kg), BMI, total fat, and visceral fat content and increased muscle mass compared to the baseline phase, but these intervention-induced changes showed no differences in comparison with the control group. The RS diet affected neither the 24-h mean glucose levels nor intra- and inter-day indices of glucose variability, HbA1c, or diurnal glucose pattern in the within- and between-group comparisons.
Conclusion
The dietary reduction of free sugars decreases body weight and body fat which may be associated with reduced total energy intake but does not affect the daily mean glucose and glycemic variability in individuals without diabetes.
Clinical trial registration
German Clinical Trials Register (DRKS); identifier: DRKS00026699.
Although many dietary patterns have been studied for weight loss, various limitations still exist. Therefore, we designed a novel weight loss diet (NWLD) with carbohydrate, protein, and fat (energy) contents of 45%, 20%, and 35%, respectively. The saturated fatty acids: monounsaturated fatty acids:polyunsaturated fatty acids ratio was 1:2:1, and the insoluble: soluble dietary fiber ratio was 2:1. We aimed to observe the effect of NWLD on weight loss and understand the underlying metabolic mechanisms. Twenty-nine male C57BL/6J mice were selected. Nine mice were fed ordinary feed in a blank control group, and the rest were fed a high-fat diet (HFD) to establish obese mouse models. Twelve weeks later, obesity models were established, and 10 obese mice were switched to NWLD feeding. Six weeks after switching the diet, the serum, intestinal feces, and kidneys of mice were collected. Obesity-related indicators, gut microbial composition, and fecal metabolite profiles of all the mice were determined, and the correlations among these indicators were analyzed. Kidney function indicators were also assessed. The results showed that the NWLD attenuated HFD-induced weight gain, serum triglycerides (TG), and inflammatory factors, optimized the body composition without kidney function impairment. Amino acid metabolism pathways and metabolites might play key roles in this process. The findings of this research imply that NWLD could be an effective nutritional remedy for managing dietary-induced obesity.
Both scientific evidence and popular diet trends have sought to identify the ideal diet for weight loss with strategies focused on either restricting carbohydrates or fat. While there is a strong physiologic rationale for either carbohydrate restriction or fat restriction to achieve a calorie deficit needed for weight loss, evidence from randomized controlled trials suggest either type of diet is effective for weight loss. The level of adherence, rather than macronutrient content, is the driver of successful weight loss.
Background & aims
Growing evidence suggests that biomarker-guided dietary interventions can optimize response to treatment. In this study, we evaluated the efficacy of the PREVENTOMCIS platform—which uses metabolomic and genetic information to classify individuals into different ‘metabolic clusters’ and create personalized dietary plans—for improving health outcomes in subjects with overweight or obesity.
Methods
A 10-week parallel, double-blinded, randomized intervention was conducted in 100 adults (82 completers) aged 18–65 years, with body mass index ≥27 but <40 kg/m², who were allocated into either a personalized diet group (n = 49) or a control diet group (n = 51). About 60% of all food was provided free-of-charge. No specific instruction to restrict energy intake was given. The primary outcome was change in fat mass from baseline, evaluated by dual energy X-ray absorptiometry. Other endpoints included body weight, waist circumference, lipid profile, glucose homeostasis markers, inflammatory markers, blood pressure, physical activity, stress and eating behavior.
Results
There were significant main effects of time (P < 0.01), but no group main effects, or time-by-group interactions, for the change in fat mass (personalized: −2.1 [95% CI -2.9, −1.4] kg; control: −2.0 [95% CI -2.7, −1.3] kg) and body weight (personalized: −3.1 [95% CI -4.1, −2.1] kg; control: −3.3 [95% CI −4.2, −2.4] kg). The difference between groups in fat mass change was −0.1 kg (95% CI −1.2, 0.9 kg, P = 0.77). Both diets resulted in significant improvements in insulin resistance and lipid profile, but there were no significant differences between groups.
Conclusion
Personalized dietary plans did not result in greater benefits over a generic, but generally healthy diet, in this 10-week clinical trial. Further studies are required to establish the soundness of different precision nutrition approaches, and translate this science into clinically relevant dietary advice to reduce the burden of obesity and its comorbidities.
Clinical trial registry
ClinicalTrials.govregistry (NCT04590989).
Carbohydrate-restricted diets and intermittent fasting (IF) have been rapidly gaining interest among the general population and patients with cardiometabolic disease, such as overweight or obesity, diabetes, and hypertension. However, there are limited expert recommendations for these dietary regimens. This study aimed to evaluate the level of scientific evidence on the benefits and harms of carbohydrate-restricted diets and IF to make responsible recommendations. A meta-analysis and systematic literature review of 66 articles on 50 randomized controlled trials (RCTs) of carbohydrate-restricted diets and 10 articles on eight RCTs of IF was performed. Based on the analysis, the following recommendations are suggested. In adults with overweight or obesity, a moderately-low carbohydrate or low carbohydrate diet (mLCD) can be considered as a dietary regimen for weight reduction. In adults with type 2 diabetes mellitus, mLCD can be considered as a dietary regimen for improving glycemic control and reducing body weight. In contrast, a very-low carbohydrate diet (VLCD) and IF are not recommended in patients with diabetes. Furthermore, no recommendations are suggested for VLCD and IF in adults with overweight or obesity, and carbohydrate-restricted diets and IF in patients with hypertension. Here, we describe the results of our analysis and the evidence for these recommendations.
Background
Carbohydrate-restricted diets and intermittent fasting (IF) have been rapidly gaining interest among the general population and patients with cardiometabolic disease, such as overweight or obesity, diabetes, and hypertension. However, there are limited expert recommendations for these dietary regimens. This study aimed to evaluate the level of scientific evidence on the benefits and harms of carbohydrate-restricted diets and IF to make responsible recommendations.
Methods
A meta-analysis and systematic literature review of 66 articles on 50 randomized controlled clinical trials (RCTs) of carbohydrate-restricted diets and ten articles on eight RCTs of IF was performed.
Results
Based on the analysis, the following recommendations are suggested. In adults with overweight or obesity, a moderately-low carbohydrate or low carbohydrate diet (mLCD) can be considered as a dietary regimen for weight reduction. In adults with type 2 diabetes, mLCD can be considered as a dietary regimen for improving glycemic control and reducing body weight. In contrast, a very-low carbohydrate diet (VLCD) and IF are recommended against in patients with diabetes. Furthermore, no recommendations are suggested for VLCD and IF in adults with overweight or obesity, and carbohydrate-restricted diets and IF in patients with hypertension.
Conclusion
Here, we describe the results of our analysis and the evidence for these recommendations.
Carbohydrate-restricted diets and intermittent fasting (IF) have been rapidly gaining interest among the general population and patients with cardiometabolic disease, such as overweight or obesity, diabetes, and hypertension. However, there are limited expert recommendations for these dietary regimens. This study aimed to evaluate the level of scientific evidence on the benefits and harms of carbohydrate-restricted diets and IF to make responsible recommendations. A meta-analysis and systematic literature review of 66 articles on 50 randomized controlled trials (RCTs) of carbohydrate-restricted diets and 10 articles on eight RCTs of IF was performed. Based on the analysis, the following recommendations are suggested. In adults with overweight or obesity, a moderately-low carbohydrate or low carbohydrate diet (mLCD) can be considered as a dietary regimen for weight reduction. In adults with type 2 diabetes mellitus, mLCD can be considered as a dietary regimen for improving glycemic control and reducing body weight. In contrast, a very-low carbohydrate diet (VLCD) and IF are recommended against in patients with diabetes. Furthermore, no recommendations are suggested for VLCD and IF in adults with overweight or obesity, and carbohydrate-restricted diets and IF in patients with hypertension. Here, we describe the results of our analysis and the evidence for these recommendations.
Spay and neuter surgeries are useful in controlling pet populations, but increase obesity risk due to increased appetite, decreased metabolic rate and decreased energy expenditure. Dietary management may help limit post-spay weight gain, but few research studies have been conducted in cats. Therefore, the objective of this study was to evaluate the effects of a high-protein, high-fiber diet (HPHF) compared to a moderate-protein, moderate-fiber diet (MPMF) in female cats following spay surgery. Twenty healthy female cats (9.5±0.1 mo) were used. After a 4-wk baseline phase with cats fed MPMF to maintain body weight (BW), 16 cats were spayed and allotted to MPMF (n=8) or HPHF (n=8), with the remaining cats being sham-operated and fed MPMF (n=4). Cats were fed to maintain BW for 12 wk, then allowed to eat up to twice that amount for another 12 wk. Daily food intake, twice weekly BW and twice weekly body condition scores (BCS) were assessed. Back fat thickness (BF) using ultrasound, body composition using dual-energy X-ray absorptiometry (DEXA), feline body mass index (fBMI), body fat percentage estimates using zoometry measurements, serum metabolites, and voluntary physical activity levels were measured prior to spay (wk 0) and every 6 wk post-spay. A treatment*time effect was observed for food intake (g/d), but not caloric intake (kcal ME/d). Caloric intake was affected by time and treatment, being reduced over the first 12 wk and reduced at higher amounts in HPHF and MPMF cats vs. sham cats. BW, BCS and body fat percentage were affected over time. Treatment*time effects were observed for blood urea nitrogen, alkaline phosphatase, and fructosamine, while blood triglycerides, total cholesterol, creatinine, total protein, phosphorus, and bicarbonate were affected by time. Physical activity was reduced over time. Our results demonstrate that spay surgery affects food intake, BW, metabolism, and physical activity of cats. Dietary intervention in this study, however, led to minor changes.
O consumo da dieta da “moda”ow Carb High fat High Protein’ (LCHFHP) está cada vez mais frequente na atualidade por ocasionar erda de peso mais rápida e consequente melhoria na qualidade de vida. A presente revisão integrativa visa identificar as implicações metabólicas, clínicas e nutricionais relacionadas ao consumo de dietas Low Carb High fat High Protein. A pesquisa bibliográfica foi realizada através de buscas nas bases de dados eletrônicas Pubmed Central e Elsevier, no período de 2006 a 2018, com a utilização dos seguintes descritores: “carbohydrate; dietary carbohydrates; diet, low carbohydrate; diet, carbohydrate-restricted; ketosis; diabetes; motor active; obesity; cardiovascular disease; protein; physical activite.” Inicialmente foram encontrados 68.219 artigos. Desses, 40 foram pré-selecionados cumprindo critérios de inclusão. Porém, dentre estes 40, 28 estavam dentro do perfil do estudo. A maioria dos estudos embora demonstrando efeitos positivos com o consumo de dieta LCHFHP, ao curto prazo, quanto à perda de peso, redução no percentual de gordura corporal, melhora da sensibilidade à insulina e no controle glicêmico e redução na utilização de medicações, mostraram que nem sempre esses efeitos foram atribuídos à redução de carboidratos na dieta. Além desses benefícios não terem sido evidenciados ao longo prazo, observou-se aumento nos níveis séricos dos biomarcadores inflamatórios, da extensão da aterosclerose e na morbidade e mortalidade cardiovascular. Realizou-se de mais estudos, principalmente ao longo prazo e com amostragem maior, no sentido de melhor averiguar os benefícios ou riscos decorrentes do consumo dessas dietas, bem como mecanismo de ação, principalmente diante das doenças crônicas não transmissíveis.
In today's digital era, nutritional information, and misinformation, is readily available for most people by media outlets, social media, and on-line streaming videos. Nutrition is of utmost interest because of its role in health, fitness, weight management, and athletic performance. Because of the public interest and information availability, qualified health care providers and exercise professionals can be an excellent source of evidence-based nutrition counseling for appropriate clients to improve overall health and athletic performance. The goal of this article is to provide a source of practitioner and client evidence-based education regarding nutritional strategies to improve athletic performance.
Background:
To date, no crossover studies have compared the effects of high-protein (HP) and low glycemic index (LGI) diets applied as starting energy-restricted diets.
Methods:
Thirty-five overweight or obese volunteers with sedentary lifestyles aged 41.4 ± 11.0 years, with body mass index (BMI) of 33.6 ± 4.2 kg/m2, without diabetes, completed an 8-week randomized crossover study of an energy-restricted diet (reduction of 30%; approximately 600 kcal/day). The anthropometric parameters, body composition, 24 h blood pressure, and basic metabolic profile were measured at baseline and after completing the two 4-week diets; i.e., the HP (protein at 30% of the daily energy intake) or LGI diet, followed by the opposite diet. All subjects maintained food diaries and attended six counselling sessions with a clinical dietitian.
Results:
The final weight loss was not significantly different when the HP diet was used first but was associated with a greater loss of fat mass: 4.6 kg (5.8; 3.0 kg) vs. 2.2 (4.5; 0.8); p < 0.025, preserved muscle mass, and reduced LDL-cholesterol.
Conclusions:
A short-term HP diet applied as a jump-start diet appeared to be more beneficial than an LGI diet, as indicated by the greater fat mass loss, preservation of muscle mass, and better effects on the lipid profile.
Understanding physiological and behavioral responses to energy imbalances is important for the management of overweight/obesity and undernutrition. Changes in body composition and physiological functions associated with energy imbalances provide the structural and functional context in which to consider psychological and behavioral responses. Compensatory changes in physiology and behavior are more pronounced in response to negative than positive energy balances. The physiological and psychological impact of weight loss (WL) occur on a continuum determined by (i) the degree of energy deficit (ED), (ii) its duration, (iii) body composition at the onset of the energy deficit, and (iv) the psychosocial environment in which it occurs. Therapeutic WL and famine/semistarvation both involve prolonged EDs, which are sometimes similar in magnitude. The key differences are that (i) the body mass index (BMI) of most famine victims is lower at the onset of the ED, (ii) therapeutic WL is intentional and (iii) famines are typically longer in duration (partly due to the voluntary nature of therapeutic WL and disengagement with WL interventions). The changes in psychological outcomes, motivation to eat, and energy intake in therapeutic WL are often modest (bearing in mind the nature of the measures used) and can be difficult to detect but are quantitatively significant over time. As WL progresses, these changes become more marked. It appears that extensive WL beyond 10%-20% in lean individuals has profound effects on body composition and physiological function. At this level of WL, there is a marked erosion of psychological functioning, which appears to run in parallel to WL. Psychological resources dwindle and become increasingly focused on alleviating escalating hunger and food seeking behavior. Functional changes in fat-free mass, characterized by catabolism of skeletal muscle and organs may be involved in the drive to eat associated with semistarvation. Higher levels of body fat mass may act as a buffer to protect fat-free mass, functional integrity and limit compensatory changes in energy balance behaviors. The increase in appetite that accompanies therapeutic WL appears to be very different to the intense and all-consuming drive to eat that occurs during prolonged semistarvation. The mechanisms may also differ but are not well understood, and longitudinal comparisons of the relationship between body structure, function, and behavior in response to differing EDs in those with higher and lower BMIs are currently lacking.
Background:
The rise in obesity has emphasised a focus on lifestyle and dietary habits. We aimed to address the debate between low-carbohydrate and low-fat diets and compare their effects on body weight, low-density lipoprotein cholesterol (LDL), high-density lipoprotein cholesterol (HDL), total cholesterol, and triglycerides in an adult population.
Method:
Medline and Web of Science were searched for randomised controlled trials (RCTs) comparing low-fat and low-carbohydrate diets up to September 2019. Three independent reviewers extracted data. Risk of bias was assessed using the Cochrane tool. The meta-analysis was stratified by follow-up time using the random-effects models.
Results:
This meta-analysis of 38 studies assessed a total of 6499 adults. At 6-12 months, pooled analyses of mean differences of low-carbohydrate vs. low-fat diets favoured the low-carbohydrate diet for average weight change (mean difference -1.30 kg; 95% CI -2.02 to -0.57), HDL (0.05 mmol/L; 95% CI 0.03 to 0.08), and triglycerides (TG) (-0.10 mmol/L; -0.16 to -0.04), and favoured the low-fat diet for LDL (0.07 mmol/L; 95% CI 0.02 to 0.12) and total cholesterol (0.10 mmol/L; 95% CI 0.02 to 0.18). Conclusion and Relevance: This meta-analysis suggests that low-carbohydrate diets are effective at improving weight loss, HDL and TG lipid profiles. However, this must be balanced with potential consequences of raised LDL and total cholesterol in the long-term.
Objective
It is controversial whether low‐carbohydrate diets are better suited for weight control and metabolic health than high‐carbohydrate diets. This study examined whether these diets induce different improvements in body composition and glucose tolerance in obese mice during caloric restriction (CR).
Methods
Male C57BL/6J mice were fed an obesogenic diet ad libitum for 18 weeks and then subjected to 6‐week progressive CR of up to 40%, using either a low‐fat or low‐carbohydrate diet with equal protein content. Mice fed a regular chow diet ad libitum served as controls. Body mass, hindlimb muscle mass, fat mass, energy expenditure, and glucose tolerance were compared between the groups.
Results
Initially low‐fat and low‐carbohydrate groups had similar body mass, which was 30% greater compared with controls. CR induced similar weight loss in low‐fat and low‐carbohydrate groups. This weight loss was mainly due to fat loss in both groups. Energy expenditure of freely moving mice did not differ between the groups. Glucose tolerance improved compared with the values before CR and in controls but did not differ between the diets.
Conclusions
Dietary carbohydrate or fat content does not affect improvements in body composition and metabolic health in obese mice exposed to CR with fixed energy and protein intake.
Trials comparing the effectiveness and safety of weight-loss diets are frequently limited by short follow-up times and high dropout rates.
In this 2-year trial, we randomly assigned 322 moderately obese subjects (mean age, 52 years; mean body-mass index [the weight in kilograms divided by the square of the height in meters], 31; male sex, 86%) to one of three diets: low-fat, restricted-calorie; Mediterranean, restricted-calorie; or low-carbohydrate, non-restricted-calorie.
The rate of adherence to a study diet was 95.4% at 1 year and 84.6% at 2 years. The Mediterranean-diet group consumed the largest amounts of dietary fiber and had the highest ratio of monounsaturated to saturated fat (P<0.05 for all comparisons among treatment groups). The low-carbohydrate group consumed the smallest amount of carbohydrates and the largest amounts of fat, protein, and cholesterol and had the highest percentage of participants with detectable urinary ketones (P<0.05 for all comparisons among treatment groups). The mean weight loss was 2.9 kg for the low-fat group, 4.4 kg for the Mediterranean-diet group, and 4.7 kg for the low-carbohydrate group (P<0.001 for the interaction between diet group and time); among the 272 participants who completed the intervention, the mean weight losses were 3.3 kg, 4.6 kg, and 5.5 kg, respectively. The relative reduction in the ratio of total cholesterol to high-density lipoprotein cholesterol was 20% in the low-carbohydrate group and 12% in the low-fat group (P=0.01). Among the 36 subjects with diabetes, changes in fasting plasma glucose and insulin levels were more favorable among those assigned to the Mediterranean diet than among those assigned to the low-fat diet (P<0.001 for the interaction among diabetes and Mediterranean diet and time with respect to fasting glucose levels).
Mediterranean and low-carbohydrate diets may be effective alternatives to low-fat diets. The more favorable effects on lipids (with the low-carbohydrate diet) and on glycemic control (with the Mediterranean diet) suggest that personal preferences and metabolic considerations might inform individualized tailoring of dietary interventions. (ClinicalTrials.gov number, NCT00160108.)
Studies of weight-control diets that are high in protein or low in glycemic index have reached varied conclusions, probably owing to the fact that the studies had insufficient power.
We enrolled overweight adults from eight European countries who had lost at least 8% of their initial body weight with a 3.3-MJ (800-kcal) low-calorie diet. Participants were randomly assigned, in a two-by-two factorial design, to one of five ad libitum diets to prevent weight regain over a 26-week period: a low-protein and low-glycemic-index diet, a low-protein and high-glycemic-index diet, a high-protein and low-glycemic-index diet, a high-protein and high-glycemic-index diet, or a control diet.
A total of 1209 adults were screened (mean age, 41 years; body-mass index [the weight in kilograms divided by the square of the height in meters], 34), of whom 938 entered the low-calorie-diet phase of the study. A total of 773 participants who completed that phase were randomly assigned to one of the five maintenance diets; 548 completed the intervention (71%). Fewer participants in the high-protein and the low-glycemic-index groups than in the low-protein-high-glycemic-index group dropped out of the study (26.4% and 25.6%, respectively, vs. 37.4%; P=0.02 and P=0.01 for the respective comparisons). The mean initial weight loss with the low-calorie diet was 11.0 kg. In the analysis of participants who completed the study, only the low-protein-high-glycemic-index diet was associated with subsequent significant weight regain (1.67 kg; 95% confidence interval [CI], 0.48 to 2.87). In an intention-to-treat analysis, the weight regain was 0.93 kg less (95% CI, 0.31 to 1.55) in the groups assigned to a high-protein diet than in those assigned to a low-protein diet (P=0.003) and 0.95 kg less (95% CI, 0.33 to 1.57) in the groups assigned to a low-glycemic-index diet than in those assigned to a high-glycemic-index diet (P=0.003). The analysis involving participants who completed the intervention produced similar results. The groups did not differ significantly with respect to diet-related adverse events.
In this large European study, a modest increase in protein content and a modest reduction in the glycemic index led to an improvement in study completion and maintenance of weight loss. (Funded by the European Commission; ClinicalTrials.gov number, NCT00390637.).
High-protein diets have been shown to increase energy expenditure (EE).
The objective was to study whether a high-protein, carbohydrate-free diet (H diet) increases gluconeogenesis and whether this can explain the increase in EE.
Ten healthy men with a mean (+/-SEM) body mass index (in kg/m(2)) of 23.0 +/- 0.8 and age of 23 +/- 1 y received an isoenergetic H diet (H condition; 30%, 0%, and 70% of energy from protein, carbohydrate, and fat, respectively) or a normal-protein diet (N condition; 12%, 55%, and 33% of energy from protein, carbohydrate, and fat, respectively) for 1.5 d according to a randomized crossover design, and EE was measured in a respiration chamber. Endogenous glucose production (EGP) and fractional gluconeogenesis were measured via infusion of [6,6-(2)H(2)]glucose and ingestion of (2)H(2)O; absolute gluconeogenesis was calculated by multiplying fractional gluconeogenesis by EGP. Body glycogen stores were lowered at the start of the intervention with an exhaustive glycogen-lowering exercise test.
EGP was lower in the H condition than in the N condition (181 +/- 9 compared with 226 +/- 9 g/d; P < 0.001), whereas fractional gluconeogenesis was higher (0.95 +/- 0.04 compared with 0.64 +/- 0.03; P < 0.001) and absolute gluconeogenesis tended to be higher (171 +/- 10 compared with 145 +/- 10 g/d; P = 0.06) in the H condition than in the N condition. EE (resting metabolic rate) was greater in the H condition than in the N condition (8.46 +/- 0.23 compared with 8.12 +/- 0.31 MJ/d; P < 0.05). The increase in EE was a function of the increase in gluconeogenesis (DeltaEE = 0.007 x Deltagluconeogenesis - 0.038; r = 0.70, R(2) = 0.49, P < 0.05). The contribution of Deltagluconeogenesis to DeltaEE was 42%; the energy cost of gluconeogenesis was 33% (95% CI: 16%, 50%).
Forty-two percent of the increase in energy expenditure after the H diet was explained by the increase in gluconeogenesis. The cost of gluconeogenesis was 33% of the energy content of the produced glucose.
Abstract
Recent trends in weight loss diets have led to a substantial increase in protein intake by individuals. As a result, the safety of habitually consuming dietary protein in excess of recommended intakes has been questioned. In particular, there is concern that high protein intake may promote renal damage by chronically increasing glomerular pressure and hyperfiltration. There is, however, a serious question as to whether there is significant evidence to support this relationship in healthy individuals. In fact, some studies suggest that hyperfiltration, the purported mechanism for renal damage, is a normal adaptative mechanism that occurs in response to several physiological conditions. This paper reviews the available evidence that increased dietary protein intake is a health concern in terms of the potential to initiate or promote renal disease. While protein restriction may be appropriate for treatment of existing kidney disease, we find no significant evidence for a detrimental effect of high protein intakes on kidney function in healthy persons after centuries of a high protein Western diet.
Background:
The possible advantage for weight loss of a diet that emphasizes protein, fat, or carbohydrates has not been established, and there are few studies that extend beyond 1 year.
Methods:
We randomly assigned 811 overweight adults to one of four diets; the targeted percentages of energy derived from fat, protein, and carbohydrates in the four diets were 20, 15, and 65%; 20, 25, and 55%; 40, 15, and 45%; and 40, 25, and 35%. The diets consisted of similar foods and met guidelines for cardiovascular health. The participants were offered group and individual instructional sessions for 2 years. The primary outcome was the change in body weight after 2 years in two-by-two factorial comparisons of low fat versus high fat and average protein versus high protein and in the comparison of highest and lowest carbohydrate content.
Results:
At 6 months, participants assigned to each diet had lost an average of 6 kg, which represented 7% of their initial weight; they began to regain weight after 12 months. By 2 years, weight loss remained similar in those who were assigned to a diet with 15% protein and those assigned to a diet with 25% protein (3.0 and 3.6 kg, respectively); in those assigned to a diet with 20% fat and those assigned to a diet with 40% fat (3.3 kg for both groups); and in those assigned to a diet with 65% carbohydrates and those assigned to a diet with 35% carbohydrates (2.9 and 3.4 kg, respectively) (P>0.20 for all comparisons). Among the 80% of participants who completed the trial, the average weight loss was 4 kg; 14 to 15% of the participants had a reduction of at least 10% of their initial body weight. Satiety, hunger, satisfaction with the diet, and attendance at group sessions were similar for all diets; attendance was strongly associated with weight loss (0.2 kg per session attended). The diets improved lipid-related risk factors and fasting insulin levels.
Conclusions:
Reduced-calorie diets result in clinically meaningful weight loss regardless of which macronutrients they emphasize. (ClinicalTrials.gov number, NCT00072995.)
1. The influence of the nutrient composition of food on energy expenditure during a 24 h period was investigated in adult volunteers. The maximum probable effect was determined using iso-energetic diets high in either protein or in glucose.
2. Two men and four women took part in the study. Their body-weights and body composition were within the normal range. Each subject lived for 28 h in a whole-body calorimeterset at 26°, on two separate occasions. During each session they ate one of the following iso-energetic diets: high-protein–low-carbohydrate or high-glucose–low-protein.Energy expenditure was determined while the subject followed a pre-set pattern of activity. A 24 h collection of urine was made and total nitrogen, creatinine and urea excretions were determined, so that heat production could be corrected for protein metabolism.
3. Two independent measures of energy expenditure were made: direct calorimetry was used to obtain heat loss partitioned into its sensible and evaporative components, while indirect calorimetry was used to estimate heat production from oxygen consumption, carbon dioxide production and N excretion. There was good agreement between the two estimates of 24 h energy expenditure: for the twelve sessions in the calorimeter the mean difference between heat production and heat loss was only 0·4 (SEM 0·39)%.
4. The results showed that nutrient composition can have a marked influence on 24 h energy expenditure in adult humans. Mean values of 8659 (SEM 230) kJ and 7735 (SEM 250) kJ were obtained for the high-protein and high-glucose diets respectively. This 12% increasein energy expenditure on the high-protein intake was significant ( P < 0·001). On the high-glucose intake, total heat loss comprised 22 and 78% evaporative and sensible heat losses respectively. The increase in heat loss onthe high-protein intake was accounted for by a 39% increase in evaporative heat loss and a 7% increase in sensible heat loss.
5. It is concluded that the composition of the nutrient intake has a greater influenceon the metabolic rate of adult humans than has been suggested by some groups of workers in recent years.
Assessment of a possible relationship between perception of satiety and diet-induced thermogenesis, with different macronutrient compositions, in a controlled situation over 24 h.
Two diets with different macronutrient compositions were offered to all subjects in randomized order.
The study was executed in the respiration chambers at the department of Human Biology, Maastricht University.
Subjects were eight females, ages 23-33 y, BMI 23+/-3 kg/m2, recruited from University staff and students.
Subjects were fed in energy balance, with protein/carbohydrate/fat: 29/61/10 and 9/30/61 percentage of energy, with fixed meal sizes and meal intervals, and a fixed activity protocol, during 36 h experiments in a respiration chamber. The appetite profile was assessed by questionnaires during the day and during meals. Diet induced thermogenesis was determined as part of the energy expenditure.
Energy balance was almost complete, with non-significant deviations. Diet-Induced-Thermogenesis (DIT) was 14.6+/-2.9%, on the high protein/carbohydrate diet, and 10.5+/-3.8% on the high fat diet (P < 0.01). With the high protein/high carbohydrate diet, satiety was higher during meals (P < 0.001; P < 0.05), as well as over 24 h (P < 0.001), than with the high fat diet. Within one diet, 24 h DIT and satiety were correlated (r = 0.6; P < 0.05). The difference in DIT between the diets correlated with the differences in satiety (r = 0.8; P < 0.01).
In lean women, satiety and DIT were synchronously higher with a high protein/high carbohydrate diet than with a high fat diet. Differences (due to the different macronutrient compositions) in DIT correlated with differences in satiety over 24 h.
Fatty acid oxidation seems to provide an important stimulus for metabolic control of food intake, because various inhibitors of fatty acid oxidation (mercaptoacetate, methyl palmoxirate, R-3-amino-4-trimethylaminobutyric acid) stimulated feeding in rats and/or mice, in particular when fed a fat-enriched diet, and long-term intravascular infusion of lipids reduced voluntary food intake in various species, including humans. The feeding response to decreased fatty acid oxidation was due to a shortening of the intermeal interval with meal size remaining unaffected. Thus, energy derived from fatty acid oxidation seems to contribute to control of the duration of postmeal satiety and meal onset. Since inhibition of glucose metabolism by 2-deoxy-D-glucose affects feeding pattern similarly, and spontaneous meals were shown to be preceded by a transient decline in blood glucose in rats and humans, a decrease in energy availability from glucose and fatty acid oxidation seems to be instrumental in eliciting eating. Since the feeding response of rats to inhibition of fatty acid oxidation was abolished by total abdominal vagotomy and pretreatment with capsaicin destroying non-myelinated afferents and attenuated by hepatic branch vagotomy, fatty acid oxidation in abdominal tissues, especially in the liver, apparently is signalled to the brain by vagal afferents to affect eating. Brain lesions and Fos immunohistochemistry were employed to identify pathways within the brain mediating eating in response to decreased fatty acid oxidation. According to these studies, the nucleus tractus solitarii (NTS) of the medulla oblongata represents the gate for central processing of vagally mediated afferent information related to fatty acid oxidation. The lateral parabrachial nucleus of the pons seems to be a major relay for pertinent ascending input from the NTS. In particular the central nucleus of the amygdala, a projection area of the parabrachial nucleus, appears to be crucial for eating in response to decreased fatty acid oxidation. As ketones are products of hepatic fatty acid oxidation that are released into the circulation and peripheral (and central) administration of 3-hydroxybutyrate reduced voluntary food intake in rats, ketones being utilized as fuels by the peripheral and central nervous system might contribute to control of eating by fatty acid oxidation, especially when high levels of circulating ketones occur. Whether a modulation of the hepatic membrane potential resulting from changes in the rate of fatty acid oxidation and/or ketogenesis represent a signal for control of eating transmitted to the brain by vagal afferents remains to be established. Recent in vivo studies investigating the effects of mercaptoacetate on the hepatic membrane potential and on afferent activity of the hepatic vagus branch are consistent with this notion. Further investigations are necessary to delineate the coding mechanisms by which fatty acid oxidation and/or ketogenesis modulate vagal afferent activity.
Despite the popularity of the low-carbohydrate, high-protein, high-fat (Atkins) diet, no randomized, controlled trials have evaluated its efficacy.
We conducted a one-year, multicenter, controlled trial involving 63 obese men and women who were randomly assigned to either a low-carbohydrate, high-protein, high-fat diet or a low-calorie, high-carbohydrate, low-fat (conventional) diet. Professional contact was minimal to replicate the approach used by most dieters.
Subjects on the low-carbohydrate diet had lost more weight than subjects on the conventional diet at 3 months (mean [+/-SD], -6.8+/-5.0 vs. -2.7+/-3.7 percent of body weight; P=0.001) and 6 months (-7.0+/-6.5 vs. -3.2+/-5.6 percent of body weight, P=0.02), but the difference at 12 months was not significant (-4.4+/-6.7 vs. -2.5+/-6.3 percent of body weight, P=0.26). After three months, no significant differences were found between the groups in total or low-density lipoprotein cholesterol concentrations. The increase in high-density lipoprotein cholesterol concentrations and the decrease in triglyceride concentrations were greater among subjects on the low-carbohydrate diet than among those on the conventional diet throughout most of the study. Both diets significantly decreased diastolic blood pressure and the insulin response to an oral glucose load.
The low-carbohydrate diet produced a greater weight loss (absolute difference, approximately 4 percent) than did the conventional diet for the first six months, but the differences were not significant at one year. The low-carbohydrate diet was associated with a greater improvement in some risk factors for coronary heart disease. Adherence was poor and attrition was high in both groups. Longer and larger studies are required to determine the long-term safety and efficacy of low-carbohydrate, high-protein, high-fat diets.
It is not clear whether varying the protein-to-carbohydrate ratio of weight-loss diets benefits body composition or metabolism.
The objective was to compare the effects of 2 weight-loss diets differing in protein-to-carbohydrate ratio on body composition, glucose and lipid metabolism, and markers of bone turnover.
A parallel design included either a high-protein diet of meat, poultry, and dairy foods (HP diet: 27% of energy as protein, 44% as carbohydrate, and 29% as fat) or a standard-protein diet low in those foods (SP diet: 16% of energy as protein, 57% as carbohydrate, and 27% as fat) during 12 wk of energy restriction (6-6.3 MJ/d) and 4 wk of energy balance ( approximately 8.2 MJ/d). Fifty-seven overweight volunteers with fasting insulin concentrations > 12 mU/L completed the study.
Weight loss (7.9 +/- 0.5 kg) and total fat loss (6.9 +/- 0.4 kg) did not differ between diet groups. In women, total lean mass was significantly (P = 0.02) better preserved with the HP diet (-0.1 +/- 0.3 kg) than with the SP diet (-1.5 +/- 0.3 kg). Those fed the HP diet had significantly (P < 0.03) less glycemic response at weeks 0 and 16 than did those fed the SP diet. After weight loss, the glycemic response decreased significantly (P < 0.05) more in the HP diet group. The reduction in serum triacylglycerol concentrations was significantly (P < 0.05) greater in the HP diet group (23%) than in the SP diet group (10%). Markers of bone turnover, calcium excretion, and systolic blood pressure were unchanged.
Replacing carbohydrate with protein from meat, poultry, and dairy foods has beneficial metabolic effects and no adverse effects on markers of bone turnover or calcium excretion.
Claims about the merits or risks of carbohydrate (CHO) vs. protein for weight loss diets are extensive, yet the ideal ratio of dietary carbohydrate to protein for adult health and weight management remains unknown. This study examined the efficacy of two weight loss diets with modified CHO/protein ratios to change body composition and blood lipids in adult women. Women (n = 24; 45 to 56 y old) with body mass indices >26 kg/m(2) were assigned to either a CHO Group consuming a diet with a CHO/protein ratio of 3.5 (68 g protein/d) or a Protein Group with a ratio of 1.4 (125 g protein/d). Diets were isoenergetic, providing 7100 kJ/d, and similar amounts of fat ( approximately 50 g/d). After consuming the diets for 10 wk, the CHO Group lost 6.96 +/- 1.36 kg body weight and the Protein Group lost 7.53 +/- 1.44 kg. Weight loss in the Protein Group was partitioned to a significantly higher loss of fat/lean (6.3 +/- 1.2 g/g) compared with the CHO Group (3.8 +/- 0.9). Both groups had significant reductions in serum cholesterol ( approximately 10%), whereas the Protein Group also had significant reductions in triacylglycerols (TAG) (21%) and the ratio of TAG/HDL cholesterol (23%). Women in the CHO Group had higher insulin responses to meals and postprandial hypoglycemia, whereas women in the Protein Group reported greater satiety. This study demonstrates that increasing the proportion of protein to carbohydrate in the diet of adult women has positive effects on body composition, blood lipids, glucose homeostasis and satiety during weight loss.
Since long-term weight maintenance (WM) is a major problem, interventions to improve WM are needed. The aim of the study was to investigate whether the addition of protein to the diet might limit weight regain after a weight loss of 5-10 % in overweight subjects. In a randomised parallel study design, 113 overweight subjects (BMI 29.3 (SD 2.5) kg/m2); age 45.1 (SD 10.4) years) followed a very-low-energy diet for 4 weeks, after which there was a 6-month period of WM. During WM, subjects were randomised into either a protein group or a control group. The protein group received 30 g/d protein in addition to their own usual diet. During the very-low-energy diet, no differences were observed between the groups. During WM, the protein group showed a higher protein intake (18 % v. 15 %; P<0.05), a lower weight regain (0.8 v. 3.0 kg; P<0.05), a decreased waist circumference (-1.2 (SD 0.7) v. 0.5 (SD 0.5 ) cm; P<0.05) and a smaller increase in respiratory quotient (0.03 (SD 0.01) v. 0.07 0.01; (SD/)P <0.05) compared with the control group. Weight regain in the protein group consisted of only fat-free mass, whereas the control group gained fat mass as well. Satiety in the fasted state before breakfast increased significantly more in the protein group than in the control group. After 6 months follow-up, body weight showed a significant group x time interaction. A protein intake of 18 % compared with 15 % resulted in improved WM in overweight subjects after a weight loss of 7.5 %. This improved WM implied several factors, i.e. improved body composition, fat distribution, substrate oxidation and satiety.
When substituted for carbohydrate in an energy-reduced diet, dietary protein enhances fat loss in women. It is unknown whether the effect is due to increased protein or reduced carbohydrate.
We compared the effects of 2 isocaloric diets that differed in protein and fat content on weight loss, lipids, appetite regulation, and energy expenditure after test meals.
This was a parallel, randomized study in which subjects received either a low-fat, high-protein (LF-HP) diet (29 +/- 1% fat, 34 +/- 0.8% protein) or a high-fat, standard-protein (HF-SP) diet (45 +/- 0.6% fat, 18 +/- 0.3% protein) during 12 wk of energy restriction (6 +/- 0.1 MJ/d) and 4 wk of energy balance (7.4 +/- 0.3 MJ/d). Fifty-seven overweight and obese [mean body mass index (in kg/m(2)): 33.8 +/- 0.9] volunteers with insulin concentrations >12 mU/L completed the study.
Weight loss (LF-HP group, 9.7 +/- 1.1 kg; HF-SP group, 10.2 +/- 1.4 kg; P = 0.78) and fat loss were not significantly different between diet groups even though the subjects desired less to eat after the LF-HP meal (P = 0.02). The decrease in resting energy expenditure was not significantly different between diet groups (LF-HP, -342 +/- 185 kJ/d; HF-SP, -349 +/- 220 kJ/d). The decrease in the thermic effect of feeding with weight loss was smaller in the LF-HP group than in the HF-SP group (-0.3 +/- 1.0% compared with -3.6 +/- 0.7%; P = 0.014). Glucose and insulin responses to test meals improved after weight loss (P < 0.001) with no significant diet effect. Bone turnover, inflammation, and calcium excretion did not change significantly.
The magnitude of weight loss and the improvements in insulin resistance and cardiovascular disease risk factors did not differ significantly between the 2 diets, and neither diet had any detrimental effects on bone turnover or renal function.
Limited evidence suggests that a higher ratio of protein to carbohydrate during weight loss has metabolic advantages.
The objective was to evaluate the effects of a diet with a high ratio of protein to carbohydrate during weight loss on body composition, cardiovascular disease risk, nutritional status, and markers of bone turnover and renal function in overweight women.
The subjects were randomly assigned to 1 of 2 isocaloric 5600-kJ dietary interventions for 12 wk according to a parallel design: a high-protein (HP) or a high-carbohydrate (HC) diet.
One hundred women with a mean (+/-SD) body mass index (in kg/m(2)) of 32 +/- 6 and age of 49 +/- 9 y completed the study. Weight loss was 7.3 +/- 0.3 kg with both diets. Subjects with high serum triacylglycerol (>1.5 mmol/L) lost more fat mass with the HP than with the HC diet (x +/- SEM: 6.4 +/- 0.7 and 3.4 +/- 0.7 kg, respectively; P = 0.035) and had a greater decrease in triacylglycerol concentrations with the HP (-0.59 +/- 0.19 mmol/L) than with the HC (-0.03 +/- 0.04 mmol/L) diet (P = 0.023 for diet x triacylglycerol interaction). Triacylglycerol concentrations decreased more with the HP (0.30 +/- 0.10 mmol/L) than with the HC (0.10 +/- 0.06 mmol/L) diet (P = 0.007). Fasting LDL-cholesterol, HDL-cholesterol, glucose, insulin, free fatty acid, and C-reactive protein concentrations decreased with weight loss. Serum vitamin B-12 increased 9% with the HP diet and decreased 13% with the HC diet (P < 0.0001 between diets). Folate and vitamin B-6 increased with both diets; homocysteine did not change significantly. Bone turnover markers increased 8-12% and calcium excretion decreased by 0.8 mmol/d (P < 0.01). Creatinine clearance decreased from 82 +/- 3.3 to 75 +/- 3.0 mL/min (P = 0.002).
An energy-restricted, high-protein, low-fat diet provides nutritional and metabolic benefits that are equal to and sometimes greater than those observed with a high-carbohydrate diet.
Essential hypertension is one of the most common diseases in the Western world, affecting about 26.4% of the adult population, and it is increasing (1). Its causes are heterogeneous and include genetic and environmental factors (2), but several observations point to an important role of the kidney in its genesis (3). In addition to variations in tubular transport mechanisms that could, for example, affect salt handling, structural characteristics of the kidney might also contribute to hypertension. The burden of chronic kidney disease is also increasing worldwide, due to population growth, increasing longevity, and changing risk factors. Although single-cause models of disease are still widely promoted, multideterminant or "multihit" models that can accommodate multiple risk factors in an individual or in a population are probably more applicable (4,5). In such a framework, nephron endowment is one potential determinant of disease susceptibility. Some time ago, Brenner and colleagues (6,7) proposed that lower nephron numbers predispose both to essential hypertension and to renal disease. They also proposed that hypertension and progressive renal insufficiency might be initiated and accelerated by glomerular hypertrophy and intraglomerular hypertension that develops as nephron number is reduced (8). In this review, we summarize data from recent studies that shed more light on these hypotheses. The data supply a new twist to possible mechanisms of the "Barker hypothesis," which proposes that intrauterine growth retardation predisposes to chronic disease in later life (9). The review describes how nephron number is estimated and its range and some determinants and morphologic correlates. It then considers possible causes of low nephron numbers. Finally, associations of hypertension and renal disease with reduced nephron numbers are considered, and some potential clinical implications are discussed.
Context:
Popular diets, particularly those low in carbohydrates, have challenged current recommendations advising a low-fat, high-carbohydrate diet for weight loss. Potential benefits and risks have not been tested adequately.
Objective:
To compare 4 weight-loss diets representing a spectrum of low to high carbohydrate intake for effects on weight loss and related metabolic variables.
Design, setting, and participants:
Twelve-month randomized trial conducted in the United States from February 2003 to October 2005 among 311 free-living, overweight/obese (body mass index, 27-40) nondiabetic, premenopausal women.
Intervention:
Participants were randomly assigned to follow the Atkins (n = 77), Zone (n = 79), LEARN (n = 79), or Ornish (n = 76) diets and received weekly instruction for 2 months, then an additional 10-month follow-up.
Main outcome measures:
Weight loss at 12 months was the primary outcome. Secondary outcomes included lipid profile (low-density lipoprotein, high-density lipoprotein, and non-high-density lipoprotein cholesterol, and triglyceride levels), percentage of body fat, waist-hip ratio, fasting insulin and glucose levels, and blood pressure. Outcomes were assessed at months 0, 2, 6, and 12. The Tukey studentized range test was used to adjust for multiple testing.
Results:
Weight loss was greater for women in the Atkins diet group compared with the other diet groups at 12 months, and mean 12-month weight loss was significantly different between the Atkins and Zone diets (P<.05). Mean 12-month weight loss was as follows: Atkins, -4.7 kg (95% confidence interval [CI], -6.3 to -3.1 kg), Zone, -1.6 kg (95% CI, -2.8 to -0.4 kg), LEARN, -2.6 kg (-3.8 to -1.3 kg), and Ornish, -2.2 kg (-3.6 to -0.8 kg). Weight loss was not statistically different among the Zone, LEARN, and Ornish groups. At 12 months, secondary outcomes for the Atkins group were comparable with or more favorable than the other diet groups.
Conclusions:
In this study, premenopausal overweight and obese women assigned to follow the Atkins diet, which had the lowest carbohydrate intake, lost more weight at 12 months than women assigned to follow the Zone diet, and had experienced comparable or more favorable metabolic effects than those assigned to the Zone, Ornish, or LEARN diets [corrected] While questions remain about long-term effects and mechanisms, a low-carbohydrate, high-protein, high-fat diet may be considered a feasible alternative recommendation for weight loss.
Trial registration:
clinicaltrials.gov Identifier: NCT00079573.
Altering the macronutrient composition of the diet influences hunger and satiety. Studies have compared high- and low-protein diets, but there are few data on carbohydrate content and ketosis on motivation to eat and ad libitum intake.
We aimed to compare the hunger, appetite, and weight-loss responses to a high-protein, low-carbohydrate [(LC) ketogenic] and those to a high-protein, medium-carbohydrate [(MC) nonketogenic] diet in obese men feeding ad libitum.
Seventeen obese men were studied in a residential trial; food was provided daily. Subjects were offered 2 high-protein (30% of energy) ad libitum diets, each for a 4-wk period-an LC (4% carbohydrate) ketogenic diet and an MC (35% carbohydrate) diet-randomized in a crossover design. Body weight was measured daily, and ketosis was monitored by analysis of plasma and urine samples. Hunger was assessed by using a computerized visual analogue system.
Ad libitum energy intakes were lower with the LC diet than with the MC diet [P=0.02; SE of the difference (SED): 0.27] at 7.25 and 7.95 MJ/d, respectively. Over the 4-wk period, hunger was significantly lower (P=0.014; SED: 1.76) and weight loss was significantly greater (P=0.006; SED: 0.62) with the LC diet (6.34 kg) than with the MC diet (4.35 kg). The LC diet induced ketosis with mean 3-hydroxybutyrate concentrations of 1.52 mmol/L in plasma (P=0.036 from baseline; SED: 0.62) and 2.99 mmol/L in urine (P<0.001 from baseline; SED: 0.36).
In the short term, high-protein, low-carbohydrate ketogenic diets reduce hunger and lower food intake significantly more than do high-protein, medium-carbohydrate nonketogenic diets.
Background: Ad libitum, low-carbohydrate diets decrease caloric intake and cause weight loss. It is unclear whether these effects are due to the reduced carbohydrate content of such diets or to their associated increase in protein intake.
Objective: We tested the hypothesis that increasing the protein content while maintaining the carbohydrate content of the diet lowers body weight by decreasing appetite and spontaneous caloric intake.
Design: Appetite, caloric intake, body weight, and fat mass were measured in 19 subjects placed sequentially on the following diets: a weight-maintaining diet (15% protein, 35% fat, and 50% carbohydrate) for 2 wk, an isocaloric diet (30% protein, 20% fat, and 50% carbohydrate) for 2 wk, and an ad libitum diet (30% protein, 20% fat, and 50% carbohydrate) for 12 wk. Blood was sampled frequently at the end of each diet phase to measure the area under the plasma concentration versus time curve (AUC) for insulin, leptin, and ghrelin.
Results: Satiety was markedly increased with the isocaloric high-protein diet despite an unchanged leptin AUC. Mean (±SE) spontaneous energy intake decreased by 441 ± 63 kcal/d, body weight decreased by 4.9 ± 0.5 kg, and fat mass decreased by 3.7 ± 0.4 kg with the ad libitum, high-protein diet, despite a significantly decreased leptin AUC and increased ghrelin AUC.
Conclusions: An increase in dietary protein from 15% to 30% of energy at a constant carbohydrate intake produces a sustained decrease in ad libitum caloric intake that may be mediated by increased central nervous system leptin sensitivity and results in significant weight loss. This anorexic effect of protein may contribute to the weight loss produced by low-carbohydrate diets.
The construct validity and the test-retest reliability of a self-administered questionnaire about habitual physical activity were investigated in young males (n = 139) and females (n = 167) in three age groups (20 to 22, 25 to 27, and 30 to 32 yr) in a Dutch population. By principal components analysis three conceptually meaningful factors were distinguished. They were interpreted as: 1) physical activity at work; 2) sport during leisure time; and 3) physical activity during leisure time excluding sport. Test-retest showed that the reliability of the three indices constructed from these factors was adequate. Further, it was found that level of education was inversely related to the work index, and positively related to the leisure-time index in both sexes. The subjective experience of work load was not related to the work index, but was inversely related to the sport index, and the leisure-time index in both sexes. The lean body mass was positively related to the work index, and the sport index in males, but was not related to the leisure-time index in either sex. These differences in the relationships support the subdivision of habitual physical activity into the three components mentioned above.
Context: The scarcity of data addressing the health effects of popular diets is an important public health concern, especially since patients and physicians are interested in using popular diets as individualized eating strategies for disease prevention. Objective: To assess adherence rates and the effectiveness of 4 popular diets (Atkins, Zone, Weight Watchers, and Ornish) for weight loss and cardiac risk factor reduction. Design, Setting, and Participants: A single-center randomized trial at an academic medical center in Boston, Mass, of overweight or obese (body mass index: mean, 35; range, 27-42) adults aged 22 to 72 years with known hypertension, dyslipidemia, or fasting hyperglycemia. Participants were enrolled starting July 18, 2000, and randomized to 4 popular diet groups until January 24, 2002. Intervention: A total of 160 participants were randomly assigned to either Atkins (carbohydrate restriction, n=40). Zone (macronutrient balance, n=40), Weight Watchers (calorie restriction, n=40), or Ornish (fat restriction, n=40) diet groups. After 2 months of maximum effort, participants selected their own levels of dietary adherence. Main Outcome Measures: One-year changes in baseline weight and cardiac risk factors, and self-selected dietary adherence rates per self-report. Results: Assuming no change from baseline for participants who discontinued the study, mean (SD) weight loss at 1 year was 2.1 (4.8) kg for Atkins (21 [53 %] of 40 participants completed, P=.009), 3.2 (6.0) kg for Zone (26 [65%] of 40 completed, P=.002), 3.0 (4.9) kg for Weight Watchers (26 [65%] of 40 completed, P<.001), and 3.3 (7.3) kg for Ornish (20 [50%] of 40 completed, P=.007). Greater effects were observed in study completers. Each diet significantly reduced the low-density lipoprotein/high-density lipoprotein (HDL) cholesterol ratio by approximately 10% (all P<.05), with no significant effects on blood pressure or glucose at 1 year. Amount of weight loss was associated with self-reported dietary adherence level (r=0.60; P<.001) but not with diet type (r=0.07; P= .40). For each diet, decreasing levels of total/HDL cholesterol, C-reactive protein, and insulin were significantly associated with weight loss (mean r=0.36, 0.37, and 0.39, respectively) with no significant difference between diets (P= .48, P= .57, P= .31, respectively). Conclusions: Each popular diet modestly reduced body weight and several cardiac risk factors at 1 year. Overall dietary adherence rates were low, although increased adherence was associated with greater weight loss and cardiac risk factor reductions for each diet group.
Background:
Low-carbohydrate diets remain popular despite a paucity of scientific evidence on their effectiveness.
Objective:
To compare the effects of a low-carbohydrate, ketogenic diet program with those of a low-fat, low-cholesterol, reduced-calorie diet.
Design:
Randomized, controlled trial.
Setting:
Outpatient research clinic.
Participants:
120 overweight, hyperlipidemic volunteers from the community.
Intervention:
Low-carbohydrate diet (initially, <20 g of carbohydrate daily) plus nutritional supplementation, exercise recommendation, and group meetings, or low-fat diet (<30% energy from fat, <300 mg of cholesterol daily, and deficit of 500 to 1000 kcal/d) plus exercise recommendation and group meetings.
Measurements:
Body weight, body composition, fasting serum lipid levels, and tolerability.
Results:
A greater proportion of the low-carbohydrate diet group than the low-fat diet group completed the study (76% vs. 57%; P = 0.02). At 24 weeks, weight loss was greater in the low-carbohydrate diet group than in the low-fat diet group (mean change, -12.9% vs. -6.7%; P < 0.001). Patients in both groups lost substantially more fat mass (change, -9.4 kg with the low-carbohydrate diet vs. -4.8 kg with the low-fat diet) than fat-free mass (change, -3.3 kg vs. -2.4 kg, respectively). Compared with recipients of the low-fat diet, recipients of the low-carbohydrate diet had greater decreases in serum triglyceride levels (change, -0.84 mmol/L vs. -0.31 mmol/L [-74.2 mg/dL vs. -27.9 mg/dL]; P = 0.004) and greater increases in high-density lipoprotein cholesterol levels (0.14 mmol/L vs. -0.04 mmol/L [5.5 mg/dL vs. -1.6 mg/dL]; P < 0.001). Changes in low-density lipoprotein cholesterol level did not differ statistically (0.04 mmol/L [1.6 mg/dL] with the low-carbohydrate diet and -0.19 mmol/L [-7.4 mg/dL] with the low-fat diet; P = 0.2). Minor adverse effects were more frequent in the low-carbohydrate diet group.
Limitations:
We could not definitively distinguish effects of the low-carbohydrate diet and those of the nutritional supplements provided only to that group. In addition, participants were healthy and were followed for only 24 weeks. These factors limit the generalizability of the study results.
Conclusions:
Compared with a low-fat diet, a low-carbohydrate diet program had better participant retention and greater weight loss. During active weight loss, serum triglyceride levels decreased more and high-density lipoprotein cholesterol level increased more with the low-carbohydrate diet than with the low-fat diet.
The aim of the study was to investigate the effects of two hypocaloric (800-kcal) diets on body weight reduction and composition, insulin sensitivity, and proteolysis in 25 normal glucose-tolerant obese women. The two diets had the following composition: 45% protein, 35% carbohydrate (CHO), and 20% fat (HP diet, 10 subjects), and 60% CHO, 20% protein, and 20% fat (HC diet, 15 subjects); both lasted 21 days. A euglycemic hyperinsulinemic (25 mU/kg/h) clamp lasting 150 minutes combined with indirect calorimetry was performed before and after the diet. Both diets induced a similar decrease in body weight and fat mass (FM), whereas fat-free mass (FFM) decreased only after the HC diet. 3-Methylhistidine (3-CH3-HIS) excretion was reduced by 48% after the HP diet and remained unchanged after the HC diet (P < .05). A significant correlation was found between the changes in FFM and in 3-CH3-HIS excretion after the diet (rs = .50, P < .02). Blood glucose remained unchanged, while insulin decreased in both diets. Free fatty acids (FFA) significantly increased only after the HC diet (P < .05). During the clamp period, glucose disposal and glucose oxidation significantly increased after the HP diet and significantly decreased after the HC diet. Opposite results were found when measuring lipid oxidation. In conclusion, our experience suggests that (1) a hypocaloric diet providing a high percentage of natural protein can improve insulin sensitivity; and (2) conversely, a hypocaloric high-polysaccharide-CHO diet decreases insulin sensitivity and is unable to spare muscle tissue.
It is unclear whether low-carbohydrate, high-protein, weight-loss diets benefit body mass and composition beyond energy restriction alone.
The objective was to use meta-regression to determine the effects of variations in protein and carbohydrate intakes on body mass and composition during energy restriction.
English-language studies with a dietary intervention of > or =4200 kJ/d (1000 kcal/d), with a duration of > or =4 wk, and conducted in subjects aged > or =19 y were considered eligible for inclusion. A self-reported intake in conjunction with a biological marker of macronutrient intake was required as a minimum level of dietary control. A total of 87 studies comprising 165 intervention groups met the inclusion criteria.
After control for energy intake, diets consisting of < or =35-41.4% energy from carbohydrate were associated with a 1.74 kg greater loss of body mass, a 0.69 kg greater loss of fat-free mass, a 1.29% greater loss in percentage body fat, and a 2.05 kg greater loss of fat mass than were diets with a higher percentage of energy from carbohydrate. In studies that were conducted for >12 wk, these differences increased to 6.56 kg, 1.74 kg, 3.55%, and 5.57 kg, respectively. Protein intakes of >1.05 g/kg were associated with 0.60 kg additional fat-free mass retention compared with diets with protein intakes < or =1.05 g/kg. In studies conducted for >12 wk, this difference increased to 1.21 kg. No significant effects of protein intake on loss of either body mass or fat mass were observed.
Low-carbohydrate, high-protein diets favorably affect body mass and composition independent of energy intake, which in part supports the proposed metabolic advantage of these diets.
The role of dietary protein in weight loss and weight maintenance encompasses influences on crucial targets for body weight regulation, namely satiety, thermogenesis, energy efficiency, and body composition. Protein-induced satiety may be mainly due to oxidation of amino acids fed in excess, especially in diets with "incomplete" proteins. Protein-induced energy expenditure may be due to protein and urea synthesis and to gluconeogenesis; "complete" proteins having all essential amino acids show larger increases in energy expenditure than do lower-quality proteins. With respect to adverse effects, no protein-induced effects are observed on net bone balance or on calcium balance in young adults and elderly persons. Dietary protein even increases bone mineral mass and reduces incidence of osteoporotic fracture. During weight loss, nitrogen intake positively affects calcium balance and consequent preservation of bone mineral content. Sulphur-containing amino acids cause a blood pressure-raising effect by loss of nephron mass. Subjects with obesity, metabolic syndrome, and type 2 diabetes are particularly susceptible groups. This review provides an overview of how sustaining absolute protein intake affects metabolic targets for weight loss and weight maintenance during negative energy balance, i.e., sustaining satiety and energy expenditure and sparing fat-free mass, resulting in energy inefficiency. However, the long-term relationship between net protein synthesis and sparing fat-free mass remains to be elucidated.
Resting metabolic rate was measured in 22 women with varying degrees of obesity. Body composition was estimated from total body potassium and from total body water, and creatinine excretion in urine was measured over a period of three weeks while the patients were on a creatinine and creatine-free reducing diet. Resting metabolic rate was highly significantly correlated with body weight, surface area, creatinine excretion and lean body mass calculated either from potassium or water measurements (P less than 0.001). Correlation with adipose tissue was less strong, and when multiple regression of both fat and lean on metabolic rate was performed, the relationship was seen to depend mostly on the mass of lean rather than adipose tissue. In obese people the water content of fat-free tissue is greater than that in normal subjects, so it is not valid to assume that fat content can be calculated accurately from a measurement of total body water.
This study examined the degree to which humans compensate for a reduction in dietary fat by increasing energy intake. Thirteen females were randomly assigned to either a low-fat diet (20-25% of calories as fat) or a control diet (35-40% fat) for 11 wk. After a 7-wk washout period, the conditions were reversed for another 11 wk. Energy intake on the low-fat diet gradually increased by 0.092 kJ/wk resulting in a total caloric compensation of 35% by the end of the 11-wk treatment period. This failure to compensate calorically on the low-fat diet resulted in a deficit of 1.22 kJ/d and a weight loss of 2.5 kg in 11 wk, twice the amount of weight lost on the control diet. These results demonstrate that body weight can be lost merely by reducing the fat content of the diet without the need to voluntarily restrict food intake.
This report describes the construction of a questionnaire to measure three dimensions of human eating behavior. The first step was a collation of items from two existing questionnaires that measure the related concepts of 'restrained eating' and 'latent obesity', to which were added items newly written to elucidate these concepts. This version was administered to several populations selected to include persons who exhibited the spectrum from extreme dietary restraint to extreme lack of restraint. The resulting responses were factor analyzed and the resulting factor structure was used to revise the questionnaire. This process was then repeated: administration of the revised questionnaire to groups representing extremes of dietary restraint, factor analysis of the results and questionnaire revision. Three stable factors emerged: (1) 'cognitive restraint of eating', (2) 'disinhibition' and (3) 'hunger'. The new 51-item questionnaire measuring these factors is presented.
Ketone bodies (acetoacetate and D-3-hydroxybutyrate) can act as oxidative fuels, as lipogenic precursors, and as regulators of metabolism. In the latter role ketone bodies can be viewed as signals of carbohydrate lack, and as such they are intimately involved in the integration of whole-body metabolism to ensure sparing of carbohydrate when it is in short supply. Our interest is primarily in the physiological importance to the intact animal of these various roles and to define them in individual extrahepatic tissues. The studies reviewed deal largely with the rat and human, but examples are drawn on occasion from other mammals. The term 'ketone bodies' is taken to mean acetoacetate and D-3-hydroxybutyrate and we make no mention of acetone, which is formed by non-enzymic breakdown of acetoacetate and is unlikely to be important in metabolism of the intact animal. Little reference is made to the early literature prior to 1960, much of which is included in previous reviews of ketone-body metabolism.
The construct validity and the test-retest reliability of a self-administered questionnaire about habitual physical activity were investigated in young males (n = 139) and females (n = 167) in three age groups (20 to 22, 25 to 27, and 30 to 32 yr) in a Dutch population. By principal components analysis three conceptually meaningful factors were distinguished. They were interpreted as: 1) physical activity at work; 2) sport during leisure time; and 3) physical activity during leisure time excluding sport. Test-retest showed that the reliability of the three indices constructed from these factors was adequate. Further, it was found that level of education was inversely related to the work index, and positively related to the leisure-time index in both sexes. The subjective experience of work load was not related to the work index, but was inversely related to the sport index, and the leisure-time index in both sexes. The lean body mass was positively related the the work index, and the sport index in males, but was not related to the leisure-time index in either sex. These differences in the relationships support the subdivision of habitual physical activity into the three components mentioned above.
An update of practical aspects of the use of labeled water for the measurement of total body water (TBW) and energy expenditure (EE) is presented as applied in Maastricht, The Netherlands. We use a 10-hour equilibration period. The isotopes for the measurement of TBW and EE are routinely administered, after collecting a background urine sample, as a last consumption before the night. Our data show an underestimate of TBW measured with isotope dilution after 4 hours (in the morning), a discrepancy which increases with the size of TBW. No such relation and no significant differences were found after 10-hour (overnight) equilibration. The ratio between the dilution space for deuterium and oxygen-18 is higher than the earlier figure of 1.03, especially in adult subjects with a high body fat content. For an observation period of EE over two weeks, samples from the second and the last voiding on the first, mid, and last day of the observation period are collected. Differences in EE calculated from morning and evening samples within the first and second week allow detection of sampling errors and if so, samples are excluded from the final calculation. Differences of EE between weeks 1 and 2 allow a check for the consistency of the subjects' physical activity level and usually fall within 10% of the average EE over the total observation interval.
This study investigated the validity of the Baecke Questionnaire, the Five City Project Questionnaire, and the Tecumseh Community Health Study Questionnaire in 19 Flemish males, using correlation and multiple stepwise regression analyses. The three questionnaires are commonly used physical activity questionnaires in epidemiological studies. The physical activity level (PAL) as measured with the doubly labelled water method was used as the criterion. The Baecke total activity index showed the highest correlation coefficient with PAL (r = 0.69, p < 0.001). Also the sweat index from the Five City Project Questionnaire, and total daily energy expenditure from the Tecumseh Community Health Study Questionnaire showed significant associations with PAL, respectively 0.57 (p < 0.05) and 0.64 (p < 0.01). Multiple stepwise regression analyses supported the findings from the correlation study. The largest individual contribution in PAL was from the activity index (45%) for the Baecke Questionnaire, the sweat index (29%) for the Five City Project Questionnaire, and total daily energy expenditure (38%) for the Tecumseh Community Health Study Questionnaire. In conclusion, the questionnaires, and certainly the Baecke Questionnaire, can provide valid data about physical activity. Therefore they are useful in epidemiological studies.
To determine the effect on plasma lipid profiles of replacement of dietary carbohydrate by low-fat, high-protein foods.
Cross-over randomized controlled trial.
Ten healthy, normolipidemic subjects (8 women and 2 men).
Subjects were randomly allocated to either a low-protein (12%) or high-protein (22%) weight-maintaining diet for 4 weeks and then switched to the alternate diet for 4 more weeks. The first 2 weeks of each diet served as an adjustment/washout period. Fat was maintained at 35% of energy, mean cholesterol intake at 230 mg per day and mean fibre intake at 24 g per day. Compliance was promoted by the use of written dietary protocols based on the food preferences of the subjects and weekly dietary consultation as required.
Mean plasma levels of total, very-low-density-lipoprotein (VLDL), low-density-lipoprotein (LDL), and high-density-lipoprotein (HDL) cholesterol, and of total and very-low-density-lipoprotein (VLDL) triglycerides. Satiety levels were self-rated on a 10-point scale.
Consumption of the high- versus the low-protein diet resulted in significant reductions in mean plasma levels of total cholesterol (3.8 v. 4.1 mmol/L, p < 0.05), VLDL cholesterol (0.20 v. 0.26 mmol/L, p < 0.02), LDL cholesterol (2.4 v. 2.6 mmol/L, p < 0.05), total triglycerides (0.69 v. 0.95 mmol/L, p < 0.005) and VLDL triglycerides (0.35 v. 0.57 mmol/L, p < 0.001), as well as in the ratio of total cholesterol to HDL cholesterol (3.1 v. 3.5, p < 0.01). A trend towards an increase in HDL cholesterol (1.26 v. 1.21 mmol/L, p = 0.30) was observed but was not statistically significant. Satiety levels tended to be higher among those eating the high-protein diet (6.1 v. 5.4, p = 0.073).
Moderate replacement of dietary carbohydrate with low-fat, high-protein foods in a diet containing a conventional level of fat significantly improved plasma lipoprotein cardiovascular risk profiles in healthy normolipidemic subjects.
To determine the effect of a 6-month very low carbohydrate diet program on body weight and other metabolic parameters.Fifty-one overweight or obese healthy volunteers who wanted to lose weight were placed on a very low carbohydrate diet (<25 g/d), with no limit on caloric intake. They also received nutritional supplementation and recommendations about exercise, and attended group meetings at a research clinic. The outcomes were body weight, body mass index, percentage of body fat (estimated by skinfold thickness), serum chemistry and lipid values, 24-hour urine measurements, and subjective adverse effects.Forty-one (80%) of the 51 subjects attended visits through 6 months. In these subjects, the mean (+/- SD) body weight decreased 10.3% +/- 5.9% (P <0.001) from baseline to 6 months (body weight reduction of 9.0 +/- 5.3 kg and body mass index reduction of 3.2 +/- 1.9 kg/m(2)). The mean percentage of body weight that was fat decreased 2.9% +/- 3.2% from baseline to 6 months (P <0.001). The mean serum bicarbonate level decreased 2 +/- 2.4 mmol/L (P <0.001) and blood urea nitrogen level increased 2 +/- 4 mg/dL (P <0.001). Serum total cholesterol level decreased 11 +/- 26 mg/dL (P = 0.006), low-density lipoprotein cholesterol level decreased 10 +/- 25 mg/dL (P = 0.01), triglyceride level decreased 56 +/- 45 mg/dL (P <0.001), high-density lipoprotein (HDL) cholesterol level increased 10 +/- 8 mg/dL (P <0.001), and the cholesterol/HDL cholesterol ratio decreased 0.9 +/- 0.6 units (P <0.001). There were no serious adverse effects, but the possibility of adverse effects in the 10 subjects who did not adhere to the program cannot be eliminated.A very low carbohydrate diet program led to sustained weight loss during a 6-month period. Further controlled research is warranted.
To compare the effects of a low-carbohydrate (LC) diet with those of a low-fat (LF) diet on weight loss and serum lipids in overweight adolescents.
A randomized, controlled 12-week trial.
Atherosclerosis prevention referral center.
Random, nonblinded assignment of participants referred for weight management. The study group (LC) (n = 16) was instructed to consume <20 g of carbohydrate per day for 2 weeks, then <40 g/day for 10 weeks, and to eat LC foods according to hunger. The control group (LF) (n = 14) was instructed to consume <30% of energy from fat. Diet composition and weight were monitored and recorded every 2 weeks. Serum lipid profiles were obtained at the start of the study and after 12 weeks.
The LC group lost more weight (mean, 9.9 +/- 9.3 kg vs 4.1 +/- 4.9 kg, P <.05) and had improvement in non-HDL cholesterol levels (P <.05). There was improvement in LDL cholesterol levels (P <.05) in the LF group but not in the LC group. There were no adverse effects on the lipid profiles of participants in either group.
The LC diet appears to be an effective method for short-term weight loss in overweight adolescents and does not harm the lipid profile.
The effects of a carbohydrate-restricted diet on weight loss and risk factors for atherosclerosis have been incompletely assessed.
We randomly assigned 132 severely obese subjects (including 77 blacks and 23 women) with a mean body-mass index of 43 and a high prevalence of diabetes (39 percent) or the metabolic syndrome (43 percent) to a carbohydrate-restricted (low-carbohydrate) diet or a calorie- and fat-restricted (low-fat) diet.
Seventy-nine subjects completed the six-month study. An analysis including all subjects, with the last observation carried forward for those who dropped out, showed that subjects on the low-carbohydrate diet lost more weight than those on the low-fat diet (mean [+/-SD], -5.8+/-8.6 kg vs. -1.9+/-4.2 kg; P=0.002) and had greater decreases in triglyceride levels (mean, -20+/-43 percent vs. -4+/-31 percent; P=0.001), irrespective of the use or nonuse of hypoglycemic or lipid-lowering medications. Insulin sensitivity, measured only in subjects without diabetes, also improved more among subjects on the low-carbohydrate diet (6+/-9 percent vs. -3+/-8 percent, P=0.01). The amount of weight lost (P<0.001) and assignment to the low-carbohydrate diet (P=0.01) were independent predictors of improvement in triglyceride levels and insulin sensitivity.
Severely obese subjects with a high prevalence of diabetes or the metabolic syndrome lost more weight during six months on a carbohydrate-restricted diet than on a calorie- and fat-restricted diet, with a relative improvement in insulin sensitivity and triglyceride levels, even after adjustment for the amount of weight lost. This finding should be interpreted with caution, given the small magnitude of overall and between-group differences in weight loss in these markedly obese subjects and the short duration of the study. Future studies evaluating long-term cardiovascular outcomes are needed before a carbohydrate-restricted diet can be endorsed.
Low-carbohydrate diets remain popular despite a paucity of scientific evidence on their effectiveness.
To compare the effects of a low-carbohydrate, ketogenic diet program with those of a low-fat, low-cholesterol, reduced-calorie diet.
Randomized, controlled trial.
Outpatient research clinic.
120 overweight, hyperlipidemic volunteers from the community.
Low-carbohydrate diet (initially, <20 g of carbohydrate daily) plus nutritional supplementation, exercise recommendation, and group meetings, or low-fat diet (<30% energy from fat, <300 mg of cholesterol daily, and deficit of 500 to 1000 kcal/d) plus exercise recommendation and group meetings.
Body weight, body composition, fasting serum lipid levels, and tolerability.
A greater proportion of the low-carbohydrate diet group than the low-fat diet group completed the study (76% vs. 57%; P = 0.02). At 24 weeks, weight loss was greater in the low-carbohydrate diet group than in the low-fat diet group (mean change, -12.9% vs. -6.7%; P < 0.001). Patients in both groups lost substantially more fat mass (change, -9.4 kg with the low-carbohydrate diet vs. -4.8 kg with the low-fat diet) than fat-free mass (change, -3.3 kg vs. -2.4 kg, respectively). Compared with recipients of the low-fat diet, recipients of the low-carbohydrate diet had greater decreases in serum triglyceride levels (change, -0.84 mmol/L vs. -0.31 mmol/L [-74.2 mg/dL vs. -27.9 mg/dL]; P = 0.004) and greater increases in high-density lipoprotein cholesterol levels (0.14 mmol/L vs. -0.04 mmol/L [5.5 mg/dL vs. -1.6 mg/dL]; P < 0.001). Changes in low-density lipoprotein cholesterol level did not differ statistically (0.04 mmol/L [1.6 mg/dL] with the low-carbohydrate diet and -0.19 mmol/L [-7.4 mg/dL] with the low-fat diet; P = 0.2). Minor adverse effects were more frequent in the low-carbohydrate diet group.
We could not definitively distinguish effects of the low-carbohydrate diet and those of the nutritional supplements provided only to that group. In addition, participants were healthy and were followed for only 24 weeks. These factors limit the generalizability of the study results.
Compared with a low-fat diet, a low-carbohydrate diet program had better participant retention and greater weight loss. During active weight loss, serum triglyceride levels decreased more and high-density lipoprotein cholesterol level increased more with the low-carbohydrate diet than with the low-fat diet.
We have previously reported that a fat-reduced high-protein diet had more favourable effects on body weight loss over 6 months than a medium-protein diet.
To extend this observation by a further 6-12 months less stringent intervention and a 24 months follow-up.
A randomised 6 months strictly controlled dietary intervention followed by 6-12 months dietary counselling period, and a subsequent 24 months follow-up, comparing an ad libitum, fat-reduced diet (30% of energy) either high in protein (25% of energy, HP) or medium in protein (12% of energy, MP).
A total of 50 overweight and obese subjects (age: 19-55 y; BMI: 26-34 kg/m(2)).
Change in body weight, body composition and blood parameters.
After 6 months, the HP group (n=23) achieved a greater weight loss than the MP group (n=23) (9.4 vs 5.9 kg) (P<0.01). After 12 months, 8% had dropped out in the HP vs 28% in the MP group (P<0.07). After 12 months, the weight loss was not significantly greater among the subjects in the HP group (6.2 and 4.3 kg), but they had a 10% greater reduction in intra-abdominal adipose tissue and more in the HP group (17%) lost >10 kg than in the MP (P<0.09). At 24 months, both groups tended to maintain their 12 months weight loss, but more than 50% were lost to follow-up.
A fat-reduced diet high in protein seems to enhance weight loss and provide a better long-term maintenance of reduced intra-abdominal fat stores.
For years, proponents of some fad diets have claimed that higher amounts of protein facilitate weight loss. Only in recent years have studies begun to examine the effects of high protein diets on energy expenditure, subsequent energy intake and weight loss as compared to lower protein diets. In this study, we conducted a systematic review of randomized investigations on the effects of high protein diets on dietary thermogenesis, satiety, body weight and fat loss. There is convincing evidence that a higher protein intake increases thermogenesis and satiety compared to diets of lower protein content. The weight of evidence also suggests that high protein meals lead to a reduced subsequent energy intake. Some evidence suggests that diets higher in protein result in an increased weight loss and fat loss as compared to diets lower in protein, but findings have not been consistent. In dietary practice, it may be beneficial to partially replace refined carbohydrate with protein sources that are low in saturated fat. Although recent evidence supports potential benefit, rigorous longer-term studies are needed to investigate the effects of high protein diets on weight loss and weight maintenance.
The scarcity of data addressing the health effects of popular diets is an important public health concern, especially since patients and physicians are interested in using popular diets as individualized eating strategies for disease prevention.
To assess adherence rates and the effectiveness of 4 popular diets (Atkins, Zone, Weight Watchers, and Ornish) for weight loss and cardiac risk factor reduction.
A single-center randomized trial at an academic medical center in Boston, Mass, of overweight or obese (body mass index: mean, 35; range, 27-42) adults aged 22 to 72 years with known hypertension, dyslipidemia, or fasting hyperglycemia. Participants were enrolled starting July 18, 2000, and randomized to 4 popular diet groups until January 24, 2002.
A total of 160 participants were randomly assigned to either Atkins (carbohydrate restriction, n=40), Zone (macronutrient balance, n=40), Weight Watchers (calorie restriction, n=40), or Ornish (fat restriction, n=40) diet groups. After 2 months of maximum effort, participants selected their own levels of dietary adherence.
One-year changes in baseline weight and cardiac risk factors, and self-selected dietary adherence rates per self-report.
Assuming no change from baseline for participants who discontinued the study, mean (SD) weight loss at 1 year was 2.1 (4.8) kg for Atkins (21 [53%] of 40 participants completed, P = .009), 3.2 (6.0) kg for Zone (26 [65%] of 40 completed, P = .002), 3.0 (4.9) kg for Weight Watchers (26 [65%] of 40 completed, P < .001), and 3.3 (7.3) kg for Ornish (20 [50%] of 40 completed, P = .007). Greater effects were observed in study completers. Each diet significantly reduced the low-density lipoprotein/high-density lipoprotein (HDL) cholesterol ratio by approximately 10% (all P<.05), with no significant effects on blood pressure or glucose at 1 year. Amount of weight loss was associated with self-reported dietary adherence level (r = 0.60; P<.001) but not with diet type (r = 0.07; P = .40). For each diet, decreasing levels of total/HDL cholesterol, C-reactive protein, and insulin were significantly associated with weight loss (mean r = 0.36, 0.37, and 0.39, respectively) with no significant difference between diets (P = .48, P = .57, P = .31, respectively).
Each popular diet modestly reduced body weight and several cardiac risk factors at 1 year. Overall dietary adherence rates were low, although increased adherence was associated with greater weight loss and cardiac risk factor reductions for each diet group.
It is not known how a low-carbohydrate, high-protein, high-fat diet causes weight loss or how it affects blood glucose levels in patients with type 2 diabetes.
To determine effects of a strict low-carbohydrate diet on body weight, body water, energy intake and expenditure, glycemic control, insulin sensitivity, and lipid levels in obese patients with type 2 diabetes.
Inpatient comparison of 2 diets.
General clinical research center of a university hospital.
10 obese patients with type 2 diabetes.
Usual diets for 7 days followed by a low-carbohydrate diet for 14 days.
Body weight, water, and composition; energy intake and expenditure; diet satisfaction; hemoglobin A1c; insulin sensitivity; 24-hour urinary ketone excretion; and plasma profiles of glucose, insulin, leptin, and ghrelin.
On the low-carbohydrate diet, mean energy intake decreased from 3111 kcal/d to 2164 kcal/d. The mean energy deficit of 1027 kcal/d (median, 737 kcal/d) completely accounted for the weight loss of 1.65 kg in 14 days (median, 1.34 kg in 14 days). Mean 24-hour plasma profiles of glucose levels normalized, mean hemoglobin A1c decreased from 7.3% to 6.8%, and insulin sensitivity improved by approximately 75%. Mean plasma triglyceride and cholesterol levels decreased (change, -35% and -10%, respectively).
The study was limited by the short duration, small number of participants, and lack of a strict control group.
In a small group of obese patients with type 2 diabetes, a low-carbohydrate diet followed for 2 weeks resulted in spontaneous reduction in energy intake to a level appropriate to their height; weight loss that was completely accounted for by reduced caloric intake; much improved 24-hour blood glucose profiles, insulin sensitivity, and hemoglobin A1c; and decreased plasma triglyceride and cholesterol levels. The long-term effects of this diet, however, remain uncertain.
Ad libitum, low-carbohydrate diets decrease caloric intake and cause weight loss. It is unclear whether these effects are due to the reduced carbohydrate content of such diets or to their associated increase in protein intake.
We tested the hypothesis that increasing the protein content while maintaining the carbohydrate content of the diet lowers body weight by decreasing appetite and spontaneous caloric intake.
Appetite, caloric intake, body weight, and fat mass were measured in 19 subjects placed sequentially on the following diets: a weight-maintaining diet (15% protein, 35% fat, and 50% carbohydrate) for 2 wk, an isocaloric diet (30% protein, 20% fat, and 50% carbohydrate) for 2 wk, and an ad libitum diet (30% protein, 20% fat, and 50% carbohydrate) for 12 wk. Blood was sampled frequently at the end of each diet phase to measure the area under the plasma concentration versus time curve (AUC) for insulin, leptin, and ghrelin.
Satiety was markedly increased with the isocaloric high-protein diet despite an unchanged leptin AUC. Mean (+/-SE) spontaneous energy intake decreased by 441 +/- 63 kcal/d, body weight decreased by 4.9 +/- 0.5 kg, and fat mass decreased by 3.7 +/- 0.4 kg with the ad libitum, high-protein diet, despite a significantly decreased leptin AUC and increased ghrelin AUC.
An increase in dietary protein from 15% to 30% of energy at a constant carbohydrate intake produces a sustained decrease in ad libitum caloric intake that may be mediated by increased central nervous system leptin sensitivity and results in significant weight loss. This anorexic effect of protein may contribute to the weight loss produced by low-carbohydrate diets.
The mechanism of protein-induced satiety remains unclear.
The objective was to investigate 24-h satiety and related hormones and energy and substrate metabolism during a high-protein (HP) diet in a respiration chamber.
Twelve healthy women aged 18-40 y were fed in energy balance an adequate-protein (AP: 10%, 60%, and 30% of energy from protein, carbohydrate, and fat, respectively) or an HP (30%, 40%, and 30% of energy from protein, carbohydrate, and fat, respectively) diet in a randomized crossover design. Substrate oxidation, 24-h energy expenditure (EE), appetite profile, and ghrelin and glucagon-like peptide 1 (GLP-1) concentrations were measured.
Sleeping metabolic rate (6.40 +/- 0.47 compared with 6.12 +/- 0.40 MJ/d; P < 0.05), diet-induced thermogenesis (0.91 +/- 0.25 compared with 0.69 +/- 0.24 MJ/d; P < 0.05), and satiety were significantly higher, and activity-induced EE (1.68 +/- 0.32 compared with 1.86 +/- 0.41; P < 0.05), respiratory quotient (0.84 +/- 0.02 compared with 0.88 +/- 0.03; P < 0.0005), and hunger were significantly lower during the HP diet. There was a tendency for a greater 24-h EE during the HP diet (P = 0.05). Although energy intake was not significantly different between the diet groups, the subjects were in energy balance during the HP diet and in positive energy balance during the AP diet. Satiety was related to 24-h protein intake (r2 = 0.49, P < 0.05) only during the HP diet. Ghrelin concentrations were not significantly different between diets. GLP-1 concentrations after dinner were higher during the HP than during the AP diet (P < 0.05).
An HP diet, compared with an AP diet, fed at energy balance for 4 d increased 24-h satiety, thermogenesis, sleeping metabolic rate, protein balance, and fat oxidation. Satiety was related to protein intake, and incidentally to ghrelin and GLP-1 concentrations, only during the HP diet.