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Intermittent versus daily calorie restriction: Which diet regimen is more effective for weight loss?
Abstract
Dietary restriction is an effective strategy for weight loss in obese individuals. The most common form of dietary restriction implemented is daily calorie restriction (CR), which involves reducing energy by 15-60% of usual caloric intake every day. Another form of dietary restriction employed is intermittent CR, which involves 24 h of ad libitum food consumption alternated with 24 h of complete or partial food restriction. Although both diets are effective for weight loss, it remains unknown whether one of these interventions produces superior changes in body weight and body composition when compared to the other. Accordingly, this review examines the effects of daily CR versus intermittent CR on weight loss, fat mass loss and lean mass retention in overweight and obese adults. Results reveal similar weight loss and fat mass loss with 3 to 12 weeks' intermittent CR (4-8%, 11-16%, respectively) and daily CR (5-8%, 10-20%, respectively). In contrast, less fat free mass was lost in response to intermittent CR versus daily CR. These findings suggest that these diets are equally as effective in decreasing body weight and fat mass, although intermittent CR may be more effective for the retention of lean mass.
... A meta-analysis of randomized controlled trials showed reductions in systolic blood pressure (SBP) and diastolic blood pressure (DBP) of ≈1 mmHg for each kilogram of weight loss (8). Effective energy restriction strategies are required, and continuous energy restriction (CER) is widely employed for weight management (9). Part of the difficulty with weight loss and maintenance by lowcalorie diets is that the body responds to CER through a series of compensatory changes in biological and behavioral determinants of body composition. ...
... The most commonly employed strategy for weight loss is daily calorie restriction, which involves reducing usual caloric intake on a daily basis by 15-60% (9). IER offers a reduced burden of calorie restriction and shows promise for achieving weight reduction goals; therefore, it may be a viable alternative to CER. ...
... The following reasons may have contributed to this discrepancy: we inferred that the Chinese elderly were less willing than young and middle-aged adults to participate at enrollment due to a lack of health education, and the baseline body weight is much lower in Asians than in Western populations, as investigations have determined (25,26). Some evidence suggests that intermittent calorie restriction may be superior to daily calorie restriction for the retention of lean mass at the expense of fat mass (9). In the present study, it also appeared as though a lower proportion of total fat-free mass was lost in response to IER when compared with CER. ...
Background and Aims: Weight-loss diets reduce body weight and improve blood pressure control in hypertensive patients. Intermittent energy restriction (IER) is an alternative to continuous energy restriction (CER) for weight reduction. We aimed to compare the effects of IER with those of CER on blood pressure control and weight loss in overweight and obese patients with hypertension during a 6-month period.
Methods: Two hundred and five overweight or obese participants (BMI 28.7 kg/m ² ) with hypertension were randomized to IER (5:2 diet, a very-low-calorie diet for 2 days per week, 500 kcal/day for women and 600 kcal/day for men, along with 5 days of a habitual diet) compared to a moderate CER diet (1,000 kcal/day for women and 1,200 kcal/day for men) for 6 months. The primary outcomes of this study were changes in blood pressure and weight, and the secondary outcomes were changes in body composition, glycosylated hemoglobin A1c (HbA1c), and blood lipids.
Results: Of the 205 randomized participants (118 women and 87 men; mean [SD] age, 50.2 [8.9] years; mean [SD] body mass index, 28.7 [2.6]; mean [SD] systolic blood pressure, 143 [10] mmHg; and mean [SD] diastolic blood pressure, 91 [9] mmHg), 173 completed the study. The intention-to-treat analysis demonstrated that IER and CER are equally effective for weight loss and blood pressure control: the mean (SEM) weight change with IER was −7.0 [0.6] kg vs. −6.8 [0.6] kg with CER, the mean (SEM) systolic blood pressure with IER was −7 [0.7] mmHg vs. −7 [0.6] mmHg with CER, and the mean (SEM) diastolic blood pressure with IER was −6 [0.5] mmHg vs. −5 [0.5] mmHg with CER, (diet by time P = 0.62, 0.39, and 0.41, respectively). There were favorable improvements in body composition, HbA1c, and blood lipid levels, with no differences between groups. Effects did not differ according to completer analysis. No severe hypoglycemia occurred in either group during the trial.
Conclusions: Intermittent energy restriction is an effective alternative diet strategy for weight loss and blood pressure control and is comparable to CER in overweight and obese patients with hypertension.
Clinical Trial Registration: http://www.chictr.org.cn , identifier: ChiCTR2000040468.
... As a result, other methods of diet control, such as time-restricted eating (TRE), have emerged as potential alternatives. TRE is one type of dietary approach that limits the daily eating window, commonly to less than 10 h per day, prolonging the fasting time [6][7][8]. Evidence from animal studies found that increased fasting time could reduce free radical production, inhibit inflammation, and increase stress resistance, leading to improved metabolic health and glucose regulation [9][10][11]. ...
... This study included patients and staff of Ramathibodi Hospital using the following eligibility criteria: adults aged 18 to 65 years, diagnosed with IFG (i.e., FPG of 100-125 mg/dL and HbA1c less than 6.5%) [25], having BMI ≥ 25 kg/m 2 , and willing to provide informed consent. Patients were excluded if they met any of the following criteria: (1) followed a ketogenic or vegetarian diet, (2) worked night shift for a minimum of 3 h between 10:00 PM and 5:00 AM on more than one day per week, (3) experienced body weight changes exceeding 5 kg in the three months prior to study enrolment, (4) were in receipt of medication to be consumed with food either before 8:00 AM or after 5:00 PM, (5) were pregnant or breastfeeding, (6) had psychiatric disorders, such as eating or mood disorders (except depression), (7) were taking corticosteroid or anti-diabetic medications, (8) had a history of bariatric surgery, or (9) had impaired nutrient absorption. ...
This randomized controlled trial is aimed at assessing the efficacy of combining time-restricted eating (TRE) with behavioral economic (BE) interventions and comparing it to TRE alone and to the usual care for reducing fasting plasma glucose (FPG), hemoglobin A1c (HbA1c), and other cardiometabolic risk factors among patients with impaired fasting glucose (IFG). Seventy-two IFG patients aged 18–65 years were randomly allocated for TRE with BE interventions (26 patients), TRE alone (24 patients), or usual care (22 patients). Mean FPG, HbA1c, and other cardiometabolic risk factors among the three groups were compared using a mixed-effect linear regression analysis. Mean body weight, FPG, HbA1c, fasting insulin, and lipid profiles did not significantly differ among the three groups. When considering only patients who were able to comply with the TRE protocol, the TRE group showed significantly lower mean FPG, HbA1c, and fasting insulin levels compared to the usual care group. Our results did not show significant differences in body weight, blood sugar, fasting insulin, or lipid profiles between TRE plus BE interventions, TRE alone, and usual care groups. However, TRE might be an effective intervention in lowering blood sugar levels for IFG patients who were able to adhere to the TRE protocol.
... TRE is one type of dietary approach that limits the daily eating window to commonly lower than 10 hours/day and prolongs fasting time. [6][7][8] Previous literature found that increased fasting time has positive effects on many metabolic signal pathways, that is, prolonged fasting stimulated autophagy and cell repair including mitochondria biogenesis resulting in better metabolic signal pathways in animals. In a human study, the TRE could significantly lower body weight but could not decline fasting plasma glucose (FPG), fasting insulin and haemoglobin A1c (HbA1c) when compared with the normal eating style in patients with metabolic syndrome. ...
... Patients will be included in this study, if they meet all of the following criteria: (1) age 18-65 years, (2) having FPG of 100-125 mg/dL with HbA1c less than 6.5% and (3) BMI ≥25 kg/m 2 . The patients will be ineligible if they are (1) currently on ketogenic or vegetarian diets, (2) doing night shift work at least ≥3 hours during 22:00-05:00 more than 1 day/week, (3) having more than 5 kg body weight changes during the 3 months before enrolment to the study, (4) taking medicines that must be taken with food in the early morning (ie, before 08:00) or late evening (ie, after 17:00), (5) pregnant or breast feeding, (6) having psychiatric disorders such as eating disorder or mood disorder but not including depression, (7) taking corticosteroid or anti-diabetic drugs, (8) having a history of bariatric surgery and (9) having impaired nutrients absorption. ...
Introduction
Impaired fasting glucose (IFG) is a significant risk factor for diabetes mellitus. Time-restricted eating (TRE) is one type of diet showing positive effects on metabolic signal pathways. However, effects of TRE on cardiometabolic risk factors in humans are limited. Additionally, compliance with TRE remains problematic despite having intention to follow the diet control. Therefore, this study aims to investigate the efficacy of TRE with behavioural economic interventions or TRE alone relative to usual care, in reducing fasting plasma glucose (FPG), haemoglobin A1c (HbA1c) and other cardiometabolic risk factors in patients with IFG.
Methods and analysis
This parallel-group, open-label randomised controlled trial will be conducted at the outpatient clinic of the Department of Family Medicine, Faculty of Medicine, Ramathibodi Hospital, Bangkok, Thailand. Patients aged 18–65 years with IFG defined as FPG 100–125 mg/dL and body mass index ≥25 kg/m ² will be recruited between October 2021 and October 2022. Patients will be randomly allocated to three groups (1:1:1 ratio) as (1) TRE with behavioural economic interventions including financial incentives and text reminders, (2) TRE alone or (3) usual care. The number of participants will be 38 per group (a total of 114). The duration of the intervention will be 12 weeks. Primary outcome is FPG levels measured at 12 weeks after randomisation. Secondary outcomes are HbA1c, body weight, systolic and diastolic blood pressure, fasting insulin, serum triglyceride, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol and high-sensitivity C reactive protein. P value of <0.05 of two-sided test will be considered as statistical significance.
Ethics and dissemination
The study protocol has been approved by the Ethics Committee of the Faculty of Medicine, Ramathibodi Hospital, Mahidol University (MURA2021/389). All patients will be informed about the details of the study and sign written informed consent before enrollment in the study. Results from this study will be published in a peer-reviewed journal.
Trial registration number
TCTR20210520002.
... A lot of dietary regimens have been recommended with proved weight loss, inflammation reduction, along with Impact of intermittent fasting on laboratory, radiological, and anthropometric parameters in NAFLD patients improved cardiovascular and metabolic markers [3]. Many regimens have been suggested for NAFLD patients: caloric restriction, low carbohydrate high fat diet, or intermittent fasting diets (IF) [4]. Notably, in IF people are allowed to eat for a restricted time and abstain food and caloric fluids for another time. ...
... Remarkably, IF is capable of reversal of insulin resistance, leading to marvelous achievements in most resistant cases. Accordingly, IF is one of the most promising regimens suggested for improving the unhealthy NAFLD parameters [4]. Being an Islamic pillar, Ramadan fasting (RF) might also be considered as a form of dry intermittent fasting ( [5] lessan). ...
Aim of the study:
Despite the ample flow of non-alcoholic fatty liver disease (NAFLD) drugs in the pipeline, lifestyle modifications are still the optimal solution of NAFLD. The aim of the study was to assess short term effects of Ramadan fasting (RF) as a sort of intermittent fasting (IF) on biochemical, radiological, and anthropometric parameters of NAFLD patients.
Material and methods:
Ninety-eight NAFLD patients were recruited and voluntarily subjected to 16 hours daily fasting for an average of 22-29 days, without special dietary recommendations. Anthropometric, laboratory and radiological parameters were measured before, at 30 days, and one month after fasting (fasting and non-fasting phases).
Results:
Patients were mostly rural (76%), hypertensive (34.7%), diabetic (43.9%), and female (76.8%), with overt criteria of metabolic syndrome (67.3%). Liver transaminases (ALT and AST) were ameliorated significantly after fasting (p ≤ 0.01), which continued in the following month (p ≤ 0.01) especially in those with elevated ALT before fasting (46%). Eleven patients (24.4%) experienced ALT normalization after one month of fasting, which was further increased to 15 (33.3%) one month later. Lipid profiles (cholesterol, triglycerides, HDL, LDL, cholesterol/HDL risk ratio) were significantly corrected following IF (p ≤ 0.01) and continuing in the next phase (p ≤ 0.010). Body mass index (BMI) lessened following the fasting (p ≤ 0.01), while no remarkable changes were noted regarding waist, hip, and triceps skin fold thickness (p ≤ 0.01). Glycemic indices (HbA1c, postprandial, HOMA-IR) and fibrosis markers (FIB-4 and APRI) were significantly ameliorated (p ≤ 0.01), while reduction in inflammatory markers was not long lasting (p ≤ 0.01).
Conclusions:
Intermittent fasting led to momentous improvements in ultrasonographic, biochemical, and anthropometric parameters of NAFLD especially in early phases and prediabetics.
... Continuous calorie restriction (CR), which is characterized by a 15%-60% reduction in caloric intake, is associated with extended healthspan and improved body condition in a number of model organisms (Weindruch & Sohal, 1997). Intermittent CR, defined as 24 h of ad libitum food consumption followed by 24 h of CR, is just as effective as continuous CR at reducing adiposity and improving body condition in mammals (Varady, 2011;Varady & Hellerstein, 2007). In addition, as compared with continuous CR, more lean body mass is preserved by intermittent CR, indicating that the latter intervention might not only be easier to sustain, but also preferable in terms of physiological outcomes. ...
... In addition, as compared with continuous CR, more lean body mass is preserved by intermittent CR, indicating that the latter intervention might not only be easier to sustain, but also preferable in terms of physiological outcomes. Intermittent fasting, an intervention that is similar to intermittent CR, but marked by a total, rather than partial, reduction in calories during the restriction period, produces similar benefits (Varady, 2011). Another extensively studied healthspan-promoting dietary intervention is the ketogenic diet (KD), which is high in fat, low in carbohydrates, and features adequate total protein and free amino acids (Newman & Verdin, 2014). ...
A sustained state of methionine restriction (MR) dramatically extends the healthspan of several model organisms. For example, continuously methionine-restricted rodents have less age-related pathology and are up to 45% longer-lived than controls. Promisingly, MR is feasible for humans, and studies have suggested that methionine-restricted individuals may receive similar benefits to rodents. However, long-term adherence to a methionine-restricted diet is likely to be challenging for many individuals. Prompted by this, and the fact that intermittent variants of other healthspan-extending interventions (i.e., intermittent fasting and the cyclic ketogenic diet) are just as effective, if not more, than their continuous counterparts, we hypothesized that an intermittent form of MR might produce similar healthspan benefits to continuous MR. Accordingly, we developed two increasingly stringent forms of intermittent MR (IMR) and assessed whether mice maintained on these diets demonstrate the beneficial metabolic changes typically observed for continuous MR. To the best of our knowledge, we show for the first time that IMR produces similar beneficial metabolic effects to continuous MR, including improved glucose homeostasis and protection against diet-induced obesity and hepatosteatosis. In addition, like continuous MR, IMR confers beneficial changes in the plasma levels of the hormones IGF-1, FGF-21, leptin, and adiponectin. Together, our findings demonstrate that the more practicable intermittent form of MR produces similar healthspan benefits to continuous MR, and thus may represent a more appealing alternative to the classical intervention.
... A 5:2 IF dietary approach, limits energy consumption to 20%-25% of energy requirements on two 'fast' days per week and ad libitum eating on the remaining 5 days. 23 IF also appears to prevent the compensatory reduction in resting energy expenditure observed in prolonged energy restriction by preserving lean body tissue. [23][24][25] For night shift workers, aligning the two fast periods with night shift would reduce overnight EI that may have benefits on both weight and metabolic responses. ...
... 23 IF also appears to prevent the compensatory reduction in resting energy expenditure observed in prolonged energy restriction by preserving lean body tissue. [23][24][25] For night shift workers, aligning the two fast periods with night shift would reduce overnight EI that may have benefits on both weight and metabolic responses. Studies in non-shift workers have shown that weight loss with IF is similar to that achieved with continuous energy restriction (CER) 26 but may promote greater improvements in insulin resistance (quantified by HOMA-IR), 27 reductions in plasma triacylglycerol (TAG) and low-density lipoprotein (LDL) cholesterol concentrations. ...
Introduction:
Shift workers are at an increased risk of developing obesity and type 2 diabetes. Eating and sleeping out of synchronisation with endogenous circadian rhythms causes weight gain, hyperglycaemia and insulin resistance. Interventions that promote weight loss and reduce the metabolic consequences of eating at night are needed for night shift workers. The aim of this study is to examine the effects of three weight loss strategies on weight loss and insulin resistance (HOMA-IR) in night shift workers.
Methods and analysis:
A multisite 18-month, three-arm randomised controlled trial comparing three weight loss strategies; continuous energy restriction; and two intermittent fasting strategies whereby participants will fast for 2 days per week (5:2); either during the day (5:2D) or during the night shift (5:2N). Participants will be randomised to a weight loss strategy for 24 weeks (weight loss phase) and followed up 12 months later (maintenance phase). The primary outcomes are weight loss and a change in HOMA-IR. Secondary outcomes include changes in glucose, insulin, blood lipids, body composition, waist circumference, physical activity and quality of life. Assessments will be conducted at baseline, 24 weeks (primary endpoint) and 18 months (12-month follow-up). The intervention will be delivered by research dietitians via a combination of face-to-face and telehealth consultations. Mixed-effect models will be used to identify changes in dependent outcomes (weight and HOMA-IR) with predictor variables of outcomes of group, time and group-time interaction, following an intention-to-treat approach.
Ethics and dissemination:
The study protocol was approved by Monash Health Human Research Ethics Committee (RES 19-0000-462A) and registered with Monash University Human Research Ethics Committee. Ethical approval has also been obtained from the University of South Australia (HREC ID: 202379) and Ambulance Victoria Research Committee (R19-037). Results from this trial will be disseminated via conference presentations, peer-reviewed journals and student theses.
Trial registration number:
Australian New Zealand Clinical Trials Registry (ACTRN-12619001035112).
... The first trial of IER was published 35 years ago [11]. Narrative reviews of IER [12][13][14] draw heavily on animal data and highlight the paucity of definitive human trials, but several studies evaluated stricter versions of IER in humans [11,[15][16][17][18][19][20][21][22][23][24][25][26][27]. Typically, participants were asked to restrict energy to 25% of their usual daily calories every other day ('alternate day fasting') or on two consecutive days per week [28] sometimes after a period on a very-low energy diet. ...
... In contrast to this, only six participants took up the offer to share their weekly progress via an online support forum, and those who did, posted information there only once or twice. (17) 10 (10) 9 (9) 36 (12) Black N (%) 21 (21) 21 (21) 13 (13) 55 (19) Asian N (%) 13 (13) 14 (14) 16 (16) 43 (14) Mixed N (%) 4 (4) 6 (6) 9 (9) 19 (6) Other N (%) 3 (3) 2 (2) 6 (6) 11 (4) Receiving free prescriptions N (%) 39 ( ...
Objective
The 5:2 diet is a popular intermittent energy restriction method of weight management that awaits further evaluation. We compared the effects of one-off 5:2 instructions with the effects of one-off standard multicomponent weight-management advice; and also examined whether additional behavioural support enhances 5:2 adherence and efficacy compared to one-off instructions.
Methods
Three hundred adults with obesity were randomised to receive a Standard Brief Advice (SBA) covering diet and physical activity (N = 100); 5:2 self-help instructions (5:2SH) (N = 100); or 5:2SH plus six once-weekly group support sessions (N = 100). Participants were followed up for one year.
Results
Adherence to 5:2SH was initially high (74% at 6 weeks), but it declined over time (31% at 6 months and 22% at one year). 5:2SH and SBA achieved similar weight-loss at six months (-1.8kg (SD = 3.5) vs -1.7kg (SD = 4.4); b = 0.23, 95%CI:-0.79–1.27, p = 0.7) and at one year (-1.9kg (SD = 4.9) vs -1.8kg (SD = 5.7), b = 0.20, 95%CI:-1.21–1.60, p = 0.79), with 18% vs 15% participants losing ≥5% of their body weight with 5:2SH and SBA, respectively at one year (RR = 0.83, 95%CI:0.44–1.54, p = 0.55). Both interventions received positive ratings, but 5:2SH ratings were significantly higher. 5:2SH had no negative effect on fat and fiber intake and physical activity compared to SBA. Compared to 5:2SH, 5:2G generated a greater weight loss at 6 weeks (-2.3kg vs -1.5kg; b = 0.74, 95%CI:1.37–0.11, p = 0.02), but by one year, the difference was no longer significant (-2.6kg vs -1.9kg, p = 0.37; ≥5% body weight loss 28% vs 18%, p = 0.10).
Conclusions
Simple 5:2 advice and multicomponent weight management advice generated similar modest results. The 5:2 diet did not undermine other health behaviours, and it received more favourable ratings. Adding initial group support enhanced 5:2 adherence and effects, but the impact diminished over time. Health professionals who provide brief weight management advice may consider including the 5:2 advice as an option.
Trial registration
ISRCTN registry (ISRCTN79408248).
... There are few different dietary regiments used in research. Calorie restriction in every day feeding is commonly used method where amount of calories is decreased and varies between 15 and 60% reduction of baseline needs [41]. Other protocols use fasting as method of decrease in calorie intake. ...
... EOD or alternate day fasting (ADF) are used in human and animal studies on benefits of dietary restrictions. Both, CR and EOD/ADF leading to weight loss, lifespan increase, other health benefits (decreased glucose, cholesterol, blood pressure) [11,41]. Apart from evident increase in lifespan and other health benefits EOD diet is not very restrictive. ...
The purpose of this study was to examine the effect of prolonged every-other day (EOD) feeding on bone trace elements. Four-week old C57BL/6 female (n = 12) and male (n = 12) mice were employed in this experiment. Animals were assigned to four groups: ad libitum—AL (males and females), EOD fed (males, females). After 9 months, the mice were sacrificed. Long bones (humerus and radius) were isolated and prepared for analysis using inductively coupled plasma optical emission spectrometry to determine the Fe, Zn, Mo, Co, Cu, Mn, Cr contents. Estimation of cathepsin K expression on bone slides was performed to determine the activity of osteoclasts in bones of EOD- and AL-fed animals. Higher content of Fe in EOD-fed females compared to AL-fed females was found. In EOD-fed males, a significantly higher amount of Mo (p < 0.005) and Co (p < 0.05) in comparison to AL-fed males was noted. Gender differences in amounts of trace elements in control AL-fed males vs. females were observed. EOD feeding influences the amount of some trace elements in long bones of female and male C57BL/6 mice. However, this is not influenced by the activity of bone cells.
... In humans, CR improves many metabolic biomarkers, including blood pressure, lipid profiles, and insulin sensitivity in men and women who are not obese (60). CR is generally more moderate in humans (20-30% versus 30-40% in rodents) and can be difficult to achieve due to limited compliance (47,194). Moreover, the risk of unwanted weight loss, specifically from adipose tissue and muscle, in patients with cancer undergoing treatment or at risk of cachexia is concerning. ...
... CR and 5:2 IER rodent diets where food consumption is tightly controlled each day in both human and rodent studies may be easier to translate. Finally, most DER clinical trials are conducted in participants who are overweight or obese (79,194,207). Therefore, investigators should consider first placing rodents on a 40-60% HFD for over 15 weeks to induce obesity prior to beginning a DER diet. ...
Diet and nutrition are intricately related to cancer prevention, growth, and treatment response. Preclinical rodent models are a cornerstone to biomedical research and remain instrumental in our understanding of the relationship between cancer and diet and in the development of effective therapeutics. However, the success rate of translating promising findings from the bench to the bedside is suboptimal. Well-designed rodent models will be crucial to improving the impact basic science has on clinical treatment options. This review discusses essential experimental factors to consider when designing a preclinical cancer model with an emphasis on incorporating these models into studies interrogating diet, nutrition, and metabolism. The aims of this review are to ( a) provide insight into relevant considerations when designing cancer models for obesity, nutrition, and metabolism research; ( b) identify common pitfalls when selecting a rodent model; and ( c) discuss strengths and limitations of available preclinical models.
Expected final online publication date for the Annual Review of Nutrition, Volume 41 is September 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
... The CALERIE trial might be one of the more prominent controlled trials of long CR, achieving 12% reduction in caloric intake, yielded an average weight loss 7.5 kg over 2 years in healthy weight men and women (Kraus et al., 2019). In Ow and Ob, a review of CR (15-60% reduction in intake) indicated that daily CR resulted in reductions of body weight and fat mass loss were 5-8%, and 10-20%, respectively (Varady, 2011). However, less is known about the temporal nature of these responses. ...
Overweight and obesity (Ow/Ob) is a risk factor for cardiometabolic disease. Caloric restriction (CR) have been investigated but little is known about the acute effects of CR and often such diets are not standardized. Thus, we aimed to assess the impact of a new standardized 3‐day CR diet (590 kcal/d intake) on cardiometabolic health in weight‐stable Ow/Ob individuals. In a single‐arm design, 15 Ow/Ob men and women were assessed pre‐post a 3‐day standardized CR diet; specifically, body weight/composition (%body fat, visceral fat score (Vfs), blood pressure (BP), and vascular stiffness (VS), resting energy expenditure (REE), substrate utilization (respiratory quotient, RQ), and blood glucose/lipid profile). CR lowered body weight (93.1 ± 15.2 to 90.67 ± 14.4 kg, p < 0.001, d = 1.9), %fat (37.2 ± 7.5 to 35.8 ± 7.5%, p = 0.002, d = 1.1), and Vfs (13.1 ± 4.5 to 12.2 ± 3.9 a.u., p = 0.002, d = 1.1), but not body water (46.3 ± 3.6 to 46.0 ± 3.6%, p = 0.29). CR lowered VS (29.8 ± 17.5 to 21.5 ± 14.5%, p = 0.05, d = 0.6), but not BP ( p > 0.05). Blood glucose (86 ± 7 to 84 ± 11 mg/dL, p = 0.33) and lipids (total cholesterol (196 ± 49 to 203 ± 54 mg/dL, p = 0.16) and TC/HDL (4.9 ± 2.4 to 6.1 ± 4.7, p = 0.13)) were unchanged. RQ decreased with CR (0.84 ± 0.01 to 0.76 ± 0.00, p < 0.001, d = 1.9), though REE was unchanged ( p = 0.83). The 3‐day CR diet significantly improved fat metabolism, body weight and composition, and vascular stiffness.
... The top 10 productive journals in the field of ADF are shown in Table 2. The characteristics of the top 20 high-cited publications [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] are summarized in Table 3, and the most highly cited publication was published in PNAS and authored by R. Michael Anson et al., in 2003 [10]. It was also the first article about ADF. ...
Alternate-day fasting (ADF) is becoming more popular since it may be a promising diet intervention for human health. Our study aimed to conduct a comprehensive bibliometric analysis to investigate current publication trends and hotspots in the field of ADF. Publications regarding ADF were identified from the Web of Science Core Collection (WOSCC) database. VOSviewer 1.6.16 and Online Analysis Platform were used to analyze current publication trends and hotspots. In total, there were 184 publications from 362 institutions and 39 countries/regions, which were published in 104 journals. The most productive countries/regions, institutions, authors, and journals were the USA, University of Illinois Chicago, Krista A. Varady, and Nutrients, respectively. The first high-cited publication was published in PNAS and authored by R. Michael Anson, and it was also the first article about ADF. The top five keywords with the highest frequency were as follows: calorie restriction, weight loss, intermittent fasting, obesity, and body weight. In conclusion, this is the first comprehensive bibliometric analysis related to ADF. The main research hotspots and frontiers are ADF for obesity and cardiometabolic risk, and ADF for several different population groups including healthy adults and patients with diabetes, nonalcoholic fatty liver disease (NAFLD), and cancer. The number of studies about ADF is relatively small, and more studies are needed to extend our knowledge about ADF, to improve human health.
... In relation to weight loss, fasting can lead to weight loss due to a reduction in calorie intake. This can also lead to a reduction in body fat and improved body composition (3). Improved insulin sensitivity has been associated with fasting, which may lead to better blood glucose control and a lower risk of type 2 diabetes (4). ...
Context: The subject of "Sport During Ramadan" focuses on the impact of fasting during the holy month of Ramadan on athletic performance and physical activity. Muslims around the world fast from sunrise to sunset during this month, abstaining from food, drink, and other physical needs. Our hypothesis suggests that during Ramadan, the fasting period can cause particular problems for athletes and people involved in sports and physical activities that require a lot of stamina and energy. Evidence Acquisition: A systematic review of the literature was conducted using the search equation "sport during Ramadan" in the PsycInfo, PubMed and ScienceDirect databases, in order to identify the 40 articles on the subject up to the year 2022. Results: Taking into account the similarities of the contents of the 40 targeted articles, 24 articles were selected. During the fasting period of the month of Ramadan, engaging in sports and exercise during Ramadan can have numerous benefits for physical and mental health. However, physical activities that require a lot of endurance and energy can pose physical health risks, including dehydration, hypoglycemia, muscle cramps, fatigue and delayed recovery. Conclusions: Participating in sports and exercise during Ramadan can have many benefits for physical and mental health, as well as spiritual awareness and community engagement. During this time, uncontrolled physical exertion can have detrimental effects on health. Proper hydration combined with a rich and balanced diet during the non-fasting period and quality sleep can help overcome the risks associated with exercising during Ramadan. It is important that Muslims prioritize their health and well-being during this time and consult a physician if necessary before engaging in physical activity.
... Intermittent nutrition and calorie restriction prolong life by reducing the incidence of diseases associated with aging (15,16). Through intermittent fasting practiced between 8 and 12 weeks, significant weight loss is achieved with the increase in insulin sensitivity (17) Significant weight loss is achieved with the control of dyslipidemia, arterial pressure and changes in body composition (18,19). In this study, the relationship between intermittent fasting and irisin levels was investigated in rats fed on a high-fat diet. ...
... The CALERIE (Comprehensive Assessment of Long-term Effects of Reducing Calorie Intake, CALERIE) trial might be one of the more prominent controlled trials of long CR, achieving 12% reduction in caloric intake, yielded an average weight loss 7.5kg over two years in healthy weight men and women [12]. In overweight and obesity, a review of CR (15-60% reduction in intake) indicated that daily CR resulted in reductions of body weight and fat mass loss were 5-8%, and 10-20%, respectively [36]. However, less is known about the temporal nature of these responses. ...
Overweight and Obesity (Ow/Ob) is a risk factor for developing cardiometabolic disease, and metabolic dysfunction. Dietary interventions, such as caloric restriction (CR), have been explored but little is known about the acute effects of CR and often such diets are not standardized. PURPOSE: To assess the impact of a standardized 3-day CR diet (~590kcal/d) on cardiometabolic health and fat metabolism in Ow/Ob individuals. METHODS: Fifteen Ow/Ob men and women were assessed pre-post 3-day CR using standardized diet; specifically, body weight/composition (% body fat, visceral fat score (Vfs), waist-hip circumferences, blood pressure and vascular stiffness, resting energy expenditure (REE), substrate utilization (respiratory quotient, RQ), and blood glucose/lipid profile. RESULTS: CR induced changes in body weight (93.1±15.2 to 90.67±14.4 kg, p<0.001, d=1.9), body mass index (32.9±4.0 to 32.0±3.7 kg/m2, p<0.001, d=1.4), body fat (37.2±7.5 to 35.8±7.5%, p=0.002, d=1.1) and Vfs (13.1±4.5 to 12.2±3.9 a.u., p=0.002, d=1.1), but not body water (46.3±3.6 to 46.0±3.6%, p=0.29, d=0.3). CR had no effect on peripheral (86±5 to 89±5 mmHg, p=0.23, d=0.3) or central mean arterial pressure (86±5 to 87±6 mmHg, p=0.44, d=0.2), but lowered augmentation index (29.8±17.5 to 21.5±14.5%, p=0.05, d=0.6). Blood glucose (86±7 to 84±11 mg/dl, p=0.33, d=0.3) and blood lipids (total cholesterol (196±49 to 203±54 mg/dl, p=0.16, d=0.4) and TC/HDL (4.9±2.4 to 6.1±4.7, p=0.13, d=0.4)) were unchanged. RQ decreased with CR (0.84±0.01 to 0.76±0.00, p<0.001, d=1.9), though REE was unchanged (1718±274 to 1722±317 kcal/d, p=0.83, d=0.1). CONCLUSION: The 3-day CR significantly improved body weight and composition and fat metabolism, with minimal cardiovascular effects.
... The primary finding of this investigation was that six weeks of intermittent (INT) dieting at a prescribed 25% reduction in energy intake presented no improvements in body composition or RMR when compared with continuous (CON) energy restriction. In terms of total weight loss, lean body mass retention, and metabolic measures, the current body of research suggests that intermittent energy restriction is at least comparable to continuous energy restriction (Davis et al., 2016;Harris et al., 2018;Peos et al., 2021) with some studies even suggesting that it may provide unique benefits Davoodi et al., 2014;Varady, 2011). However, the vast majority of literature on intermittent energy restriction has focused on more extreme forms of energy intake undulation such as alternate-day fasting (Seimon et al., 2015), and many do not involve intermittent periods in which a return to true energy balance is both prescribed and achieved -that is, in most studies of intermittent energy restriction to date, either spontaneous or formal energy restriction is continued to some extent throughout the "feast" periods . ...
The purpose of this study was to examine the effects of intermittent versus continuous energy restriction on body composition, resting metabolic rate, and eating behaviors in resistance-trained females. Thirty-eight resistance-trained females (mean ± standard deviation age: 22.3±4.2 years) were randomized to receive either six weeks of a continuous 25% reduction in energy intake (n= 18), or one week of energy balance after every two weeks of 25% energy restriction (eight weeks total; n= 20). Participants were instructed to ingest 1.8 g protein/kilogram bodyweight per day and completed three weekly supervised resistance training sessions throughout the intervention. There were no differences between groups for changes over time in body composition, resting metabolic rate, or seven of the eight measured eating behavior variables (p > 0.05). However, a significant group-by-time interaction for disinhibition (p < 0.01) from the Three-Factor Eating Questionnaire was observed, with values (± standard error) in the continuous group increasing from 4.91 ± 0.73 to 6.17 ± 0.71, while values in the intermittent group decreased from 6.80 ± 0.68 to 6.05 ± 0.68. Thus, diet breaks do not appear to induce improvements in body composition or metabolic rate in comparison with continuous energy restriction over six weeks of dieting, but may be employed for those who desire a short-term break from an energy-restricted diet without fear of fat regain. While diet breaks may reduce the impact of prolonged energy restriction on measures of disinhibition, they also require a longer time period that may be less appealing for some individuals.
... Numerous research trials have contrasted calorie restriction with intermittent fasting, though up till now there is no study comparing the different protocols of intermittent fasting with each other. One study compared calorie restriction and intermittent fasting in patients with type 2 diabetes mellitus (Varady, 2011); they established that although calorie restriction is better with reference to reduction in body weight, intermittent fasting and calorie restriction (CR) had similar effects in reduction of visceral fat, insulin resistance and fasting insulin. In nondiabetic persons, intermittent fasting enhances metabolic parameters (Anson et al., 2003). ...
Fasting can be observed by consuming nothing or a limited quantity of calories (either food or drinks) for a certain period, and the duration varies explicitly from 12 hours to a few days. Numerous religious communities integrate the duration of fasting into their habits, including Muslims, Jews, Hindus, Christians and Buddhists. However, the duration and time vary in all religions. The Muslims fast throughout the entire month of Ramadan from early morning till evening, whereas people from other religions fast on different occasions at a specific time and for specific days. There are substantial medicinal benefits of fasting, and even doctors of contemporary medicines advise their patients to fast for the management of metabolic diseases, obesity and hormonal fluctuations so that the patient’s body gets in a balanced state. This chapter will discuss the introduction of fasting, the historical importance of fasting in different religions, physiological changes in tissues and systems of the body of a fasting person, what a Daniel fast is and what its benefits are, potential benefits of intermittent fasting, metabolic effects of fasting, the impact of fasting on various hormones, how fasting enhances life expectancy and other health benefits of fasting.
... 5,10-12 The weight reduction caused by fasting diets has been addressed in several review studies. 16,99,100 Briefly, the weight loss outcomes of alternate-day fasting diets are comparable with those for very-low-calorie diets, often with a greater fat mass decrease and further maintenance of the lean mass. 16 A 3 week-12 week intermittent fasting diet reduced weight by 4%-8%, a similar amount to that with a conventional caloric-restriction diet; nonetheless, its efficiency was higher in lean mass maintenance. ...
Nonalcoholic fatty liver disease (NAFLD) is the most common liver disease in the world. There is no confirmed treatment for NAFLD as yet. Recently, fasting regimens and their relationship to NAFLD have drawn a great deal of attention in the literature. We review the current evidence that supports fasting diets as an adjunctive therapeutic strategy for patients with NAFLD and address potential action mechanisms. We reason that the fasting diets might be a promising approach for modulating hepatic steatosis, fibroblast growth factors 19 and 21 signaling, lipophagy, and the metabolic profile.
... Data from some human studies suggest that compared to cCR, iCR shows greater increases in insulin sensitivity [188,189], faster weight loss [188], greater reductions in fat mass [188], better retention of lean mass [199], alterations in gut microbiota [200,201], inflammation reduction [188,202], and better LAR [188], while systematic reviews deem iCR and cCR equivalent for weight/fat loss and metabolic changes [203,204] although primarily only women were studied [205]. While it seems plausible that iCR may allow more flexibility for adherence and for avoiding weight regain, long-term effects in humans are unknown. ...
Obesity represents an important risk factor for prostate cancer, driving more aggressive disease, chemoresistance, and increased mortality. White adipose tissue (WAT) overgrowth in obesity is central to the mechanisms that lead to these clinical observations. Adipose stromal cells (ASCs), the progenitors to mature adipocytes and other cell types in WAT, play a vital role in driving PCa aggressiveness. ASCs produce numerous factors, especially chemokines, including the chemokine CXCL12, which is involved in driving EMT and chemoresistance in PCa. A greater understanding of the impact of WAT in obesity-induced progression of PCa and the underlying mechanisms has begun to provide opportunities for developing interventional strategies for preventing or offsetting these critical events. These include weight loss regimens, therapeutic targeting of ASCs, use of calorie restriction mimetic compounds, and combinations of compounds as well as specific receptor targeting strategies.
... In the present study, LBM loss following intermittent fasting was less (~17.5%, 0.8 kg) which may support previous suggestions that IF leads to greater attenuation of LBM loss compared to continuous energy restriction [40], though more recent evidence suggests otherwise [41]. On the contrary, reductions in LBM between energy-restricted diets could be dependent on the percentage of weight loss, with participants who lose more weight (i.e., >10% of their body weight) likely to lose greater amounts of LBM. ...
The popularity of intermittent fasting (IF) and high intensity (sprint) interval training (SIT) has increased in recent years amongst the general public due to their purported health benefits and feasibility of incorporation into daily life. The number of scientific studies investigating these strategies has also increased, however, very few have examined the combined effects, especially on body composition and cardiometabolic biomarkers, which is the primary aim of this investigation. A total of thirty-four male and female participants (age: 35.4 ± 8.4 y, body mass index (BMI): 31.3 ± 3.5 kg/m2, aerobic capacity (VO2peak) 27.7 ± 7.0 mL·kg-1·min-1) were randomized into one of three 16-week interventions: (1) 5:2 IF (2 non-consecutive days of fasting per week, 5 days on ad libitum eating), (2) supervised SIT (3 bouts per week of 20s cycling at 150% VO2peak followed by 40 s of active rest, total 10 min duration), and (3) a combination of both interventions. Body composition, haemodynamic and VO2peak were measured at 0, 8 and 16 weeks. Blood samples were also taken and analysed for lipid profiles and markers of glucose regulation. Both IF and IF/SIT significantly decreased body weight, fat mass and visceral fat compared to SIT only (p < 0.05), with no significant differences between diet and diet + exercise combined. The effects of diet and/or exercise on cardiometabolic biomarkers were mixed. Only exercise alone or with IF significantly increased cardiorespiratory fitness. The results suggest that energy restriction was the main driver of body composition enhancement, with little effect from the low volume SIT. Conversely, to achieve benefits in cardiorespiratory fitness, exercise is required.
... The comparison is with CER [18] or daily calorie restriction, which reduces 15-60% of the baseline calorie needs each day. ...
There is considerable heterogeneity across the evidence regarding the effects of intermittent energy restriction and continuous energy restriction among adults with overweight or obesity which presents difficulties for healthcare decision-makers and individuals. This overview of systematic reviews aimed to evaluate and synthesize the existing evidence regarding the comparison of the two interventions. We conducted a search strategy in eight databases from the databases’ inception to December 2021. The quality of 12 systematic reviews was assessed with A Measurement Tool to Assess Systematic Reviews 2 (AMSTAR 2) and the Grading of Recommendations Assessment, Development and Evaluation (GRADE). One review was rated as high quality, 1 as moderate, 4 as low, and 6 as critically low. A meta-analysis of the original studies was conducted for comparison of primary intermittent energy restriction protocols with continuous energy restriction. Intermittent energy restriction did not seem to be more effective in weight loss compared with continuous energy restriction. The advantages of intermittent energy restriction in reducing BMI and waist circumference and improvement of body composition were not determined due to insufficient evidence. The evidence quality of systematic reviews and original trials remains to be improved in future studies.
... Uncontrolled food intake and weight gain could be of concern among those aiming for weight loss. Fasting is one of the aids to weight loss as it involves spontaneous caloric restriction [58]. Furthermore, this practice has been shown to aid in internal control over negative eating behaviors such as overeating and consumption of unhealthy foods [59]. ...
The COVID-19 pandemic has been affecting our lifestyles, such as work, living, and health. In Malaysia, the Restriction of Movement Order (RMO) was first announced in March 2020 to curb the spread of the virus. Since then, many Malaysians have been confined to their own home. This new lifestyle can cause a change of eating habits where healthy eating may be a challenge. Hence, our qualitative study explored the challenges and strategies for healthy eating during the first wave of the COVID-19 home confinement period among working adults overweight and obese in Malaysia. Eleven participants were individually interviewed through phone calls. The interviews were audio-recorded, transcribed verbatim, and then coded with NVIVO 12 based on thematic analysis. We found that social pressure, changes in the social setting, more free time to access food, and extra stock of unhealthy foods at home were among the challenges to healthy eating. Some participants countered these perceived challenges by reducing unhealthy food stock, limiting kitchen visits, and utilizing self-monitoring apps to monitor their calorie intake. Social media was not consistently perceived to influence their eating behavior during this period. We conclude that COVID-19 home confinement has created challenges to healthy eating habits among overweight and obese adults with overweight and obesity. Our study provides evidence that vulnerable groups such as overweight and obese individuals require specific nutritional support during pandemic-related confinement to enhance eating self-efficacy.
... The Alternate Day Fasting (ADF) protocol, which consists of 24-h fasting, has already been shown to maintain lean mass (15) or deplete fat-free mass (9) in the absence of physical exercise. Using the IF strategy in obesity appears to have a greater ability to retain muscle mass, as opposed to continuous caloric restriction (16). However, there are few studies investigating the impact of the 5:2 intervention on fat-free mass, as current discussions strongly emphasize the effects on weight and body fat loss and the study by Patikorn et al. (17) fortify this idea by suggest that 5:2 intermittent fasting protocol applied for a long period can result in weight and fat mass loss in overweight or obese adults in a way that is superior to time-restricted eating or ADF (17). ...
Background
Intermittent fasting (IF) is a dietary approach that is widely popular due to its effects on weight and body fat loss, but it does not appear to ensure muscle mass preservation. Incorporating high-intensity interval training (HIIT) into an individual’s routine could be an attractive and viable therapeutic option for improving body composition, lifestyle and health promotion. Problematizing the emerging situation of fighting obesity, led us to clarify gaps about IF and hypothesize that IF and HIIT in conjunction may protect against muscle mass decline without impairing nitrogen balance (NB), in addition to improving the physical fitness of women with obesity.
Objectives
To evaluate the effects of IF alone and combined with HIIT on body composition, NB and strength and physical fitness in women with obesity.
Methods
Thirty-six women (BMI 34.0 ± 3.2; 32.2 ± 4.4 years) participated and were randomly distributed into three groups: (1) Intermittent fasting combined with exercise group (IF + EX); (2) Exercise group (EX); and (3) Intermittent fasting group (IF). The interventions took place over 8 weeks and all evaluations were performed pre and post-intervention. The HIIT circuit was performed 3x/week, for 25 mins/session, at 70–85% of the maximum heart rate. The intermittent fasting protocol was a 5:2 diet with two meals within 6 h on fasting days, being 25% of total energy intake, plus 18 h of complete fasting. The protocol was performed 2x/week and 5 days of ad libitum ingestion. Resting metabolic rate (RMR) was measured by indirect calorimetry, body composition by BodPod ® , NB from urinary nitrogen, food consumption by food records and physical and strength performance were measured by physical tests. ANOVA two-way repeated measures mixed model was performed followed by Sidak post hoc ( p < 0.05). This project was registered in ClinicalTrials.gov , NCT05237154.
Results
There were a reduction in body weight ( P = 0.012) and BMI ( P = 0.031) only in the IF + EX group. There was body fat loss in the IF + EX group (−4%, P < 0.001) and in the EX group (−2.3%, P = 0.043), an increase in fat-free mass in the IF + EX group (+3.3%, P < 0.001) and also in the EX group (+2%, P = 0.043), without differences between groups and the IF group showed no changes. The NB was equilibrium in all groups. All parameters of aerobic capacity and strength improved.
Conclusion
Combining IF with HIIT can promote increments in fat-free mass, NB equilibrium and improve physical fitness and strength.
... As for the comparison between ADF and CR, the subgroup analysis based on the dietary pattern of IF found that ADF had no greater beneficial effects than CR in our study, but other studies showed a difference in superior compliance, FM, and FFM in the ADF group (11,63). Furthermore, ADF also did not have the burden of chronic poor feeding and other adverse outcomes compared to CR (58). ...
Background
The popularity of applying intermittent fasting (IF) has increased as more and more people are trying to avoid or alleviate obesity and metabolic disease. This study aimed to systematically explore the effects of various IF in humans.
Methods
The randomized controlled trials (RCTs) related to IF vs. non-intervention diet or caloric restriction (CR) were retrieved in PubMed, Web of Science, Cochrane Library database, and Embase. Extraction outcomes included, but were not limited to, weight, body mass index (BMI), waist circumference (WC), fasting glucose, and triglyceride (TG).
Results
This study includes 43 RCTs with 2,483 participants. The intervention time was at least 1 month, and the median intervention time was 3 months. Contrasting results between IF and non-intervention diet showed that participants had lower weight (weighted mean difference (WMD) = 1.10, 95% CI: 0.09–2.12, p = 0.03) and BMI after IF (WMD = 0.38, 95% CI: 0.08–0.68, p = 0.01). The WC of participants after IF decreased significantly compared with the non-intervention diet (WMD = 1.02, 95% CI: 0.06–1.99, p = 0.04). IF regulated fat mass (FM) more effectively than non-intervention diet (WMD = 0.74, 95% CI: 0.17–1.31, p = 0.01). The fat-free mass of people after IF was higher (WMD = −0.73, 95% CI: (−1.45)–(−0.02), p = 0.05). There was no difference in fasting blood glucose concentrations between participants in the after IF and non-intervention diet groups. The results of insulin concentrations and HOMA-IR, though, indicated that IF was significantly more beneficial than non-intervention diet (standard mean difference (SMD) = −0.21, 95% CI: 0.02–0.40, p = 0.03, and WMD = 0.35, 95% CI: 0.04–0.65, p = 0.03, respectively). Cholesterol and TG concentrations in participants after IF were also lower than that after a nonintervention diet (SMD = 0.22, 95% CI: 0.09–0.35, p = 0.001 and SMD = 0.13, 95% CI: 0.00–0.26, p = 0.05, respectively). IF outcomes did not differ from CR except for reduced WC.
Conclusion
Intermittent fasting was more beneficial in reducing body weight, WC, and FM without affecting lean mass compared to the non-intervention diet. IF also effectively improved insulin resistance and blood lipid conditions compared with non-intervention diets. However, IF showed less benefit over CR.
... Time-restricted feeding (TRF) (e.g., alternate-day fasting, fasting twice a week, or Ramadan fasting) is the most studied form of IF [29]. TRF entails the abstinence from all food during a number of hours and has been found to improve body mass and composition [36][37][38][39] and protect normal cells and organs from different toxins [28]. ...
Objective: This study examined the effect of 12 wk of time-restricted feeding (TRF) on complete blood cell counts, natural killer cells, and muscle performance in 20-and 50-year-old men. Methods: Forty active and healthy participants were randomly divided into young experimental, young control, aged experimental, and aged control group. Experimental groups participated in TRF. Before (P1) and after (P2) TRF, participants performed a maximal exercise test to quantify muscle power. Resting venous blood samples were collected for blood count calculation. Results: No changes were identified in muscle power in all groups after TRF (P > 0.05). At P1, red cells, hemoglobin, and hematocrit were significantly higher in young participants compared with elderly participants (P < 0.05). At P2, this age effect was not found in red cells between the young experimental group and the aged experimental group (P > 0.05). At P1, white blood cells and neutrophils were significantly higher in young participants compared with elderly participants (P < 0.05). At P2, only neutrophils decreased significantly (P < 0.05) in experimental groups without significant (P > 0.05) difference among them. Lymphocytes decreased significantly in the aged experimental group at P2 (P < 0.05), whereas NKCD16 + and NKCD56 + decreased significantly in experimental groups at P2 (P < 0.05). TRF had no effect on CD3, CD4 + , and CD8 + levels (P > 0.05). Conclusion: TRF decreases hematocrit, total white blood cells, lymphocytes, and neutrophils in young and older men. TRF may be effective in preventing inflammation by decreasing natural killer cells. As such, TRF could be a lifestyle strategy to reduce systemic low-grade inflammation and age-related chronic diseases linked to immunosenescence, without compromising physical performance.
... A strict IF of 4 to 24 weeks reduced subject body mass by 4-10% [55]. Other scholars pointed out that the role of IF in weight loss is not significantly different from that of a calorie-restricted diet, consistent with our analysis; however, IF was better at maintaining lean body mass [17]. ...
We conducted a systematic review and meta-analysis of randomized clinical trials and pilot trial studies to compare the effectiveness of intermittent fasting (IF) and continuous calorie restriction (CCR) in overweight and obese people. The parameters included body mass index (BMI), body weight, and other metabolism-related indicators. A systematic search in PubMed, Embase, Cochrane Library, and Web of Science was conducted up to January 2022. Standardized mean differences (SMDs) with 95% confidence intervals (CIs) were used to measure the effectiveness. Publication bias was assessed using Egger’s test. The stability of the results was evaluated using sensitivity analyses. The significance of body weight change (SMD = −0.21, 95% CI (−0.40, −0.02) p = 0.028) was more significant after IF than CCR. There was no significant difference in BMI (SMD = 0.02, 95% CI (−0.16, 0.20) p = 0.848) between IF and CCR. These findings suggest that IF may be superior to CCR for weight loss in some respects.
... Previous studies comparing the influence of IER and CER diets were performed mainly on healthy, but obese, individuals [93]. In most reports with short-term trials of IER diets or CER diets, both of them seem to have a similar impact on different metabolic parameters such as decreasing the levels of total cholesterol, LDL, triglycerides, fasting glucose, and insulin [33,94,95]. Furthermore, CER and IER appear to have had a similar impact on weight loss, reduction in BMI, and decrease in hip or waist circumferences [33,62,79,96,97]. ...
Obesity is a disease defined by an elevated body mass index (BMI), which is the result of excessive or abnormal accumulation of fat. Dietary intervention is fundamental and essential as the first-line treatment for obese patients, and the main rule of every dietary modification is calorie restriction and consequent weight loss. Intermittent energy restriction (IER) is a special type of diet consisting of intermittent pauses in eating. There are many variations of IER diets such as alternate-day fasting (ADF) and time-restricted feeding (TRF). In the literature, the IER diet is known as an effective method for bodyweight reduction. Furthermore, IER diets have a beneficial effect on systolic or diastolic pressure, lipid profile, and glucose homeostasis. In addition, IER diets are presented as being as efficient as a continuous energy restriction diet (CER) in losing weight and improving metabolic parameters. Thus, the IER diet could present an alternative option for those who cannot accept a constant food regimen.
... People can calorically restrict while feeling hungry, and this approach has already been demonstrated in various mammalian species to enhance life span, increase numerous physiological indicators, and lower metabolic parameters for chronic illness (1,2). There are numerous types of intermittent fasting (IF), all of which involve fasting periods that last longer than an overnight fast and involve limited meal time-windows, with or without calorie restriction (3,4). ...
Background
In recent years, intermittent fasting (IF) has gained popularity in the health and wellness in the world. There are numerous types of IF, all of which involve fasting periods that last longer than an overnight fast and involve limited meal time-windows, with or without calorie restriction. The objective of this review is to summarize the current evidence for the effects of Ramadan and non-Ramadan IF on gut microbiome.
Methods
We explored PubMed, Scopus, Web of Science, and Google Scholar according to the PRISMA criteria (Preferred Reporting Items for Systematic Reviews and Meta-Analysis). Animal and human studies were screened and reviewed separately by two researchers.
Results
Twenty-eight studies were selected after screening. Some of the studies were performed on animal models and some on humans. The results of these studies indicate a significant shift in the gut microbiota, especially an increase in the abundance of Lactobacillus and Bifidobacteria following fasting diets. The results of some studies also showed an increase in the bacterial diversity, decrease inflammation and increased production of some metabolites such as short-chain fatty acids (SCFAs) in individuals or samples under fasting diets. Moreover, Ramadan fasting, as a kind of IF, improves health parameters through positive effects on some bacterial strains such as Akkermansia muciniphila and Bacteroide . However, some studies have reported adverse effects of fasting diets on the structure of the microbiome.
Conclusion
In general, most studies have seen favorable results following adherence from the fasting diets on the intestinal microbiome. However, because more studies have been done on animal models, more human studies are needed to prove the results.
... Among the factors that enhance GH secretion, the role of fasting and ghrelin has been well-documented [67]. In a review comparing IF and caloric restriction, it was found that weight loss observed during IF was associated with a greater maintenance of lean mass, and GH has been proposed as one of the factors that could explain it, as it may be secreted to a greater extent in conditions of prolonged food deprivation rather than in a caloric restriction approach [68]. Moreover, IGF1, acts as a neurotrophic factor due to its capacity to enhance neuroplasticity and protecting neurons against metabolic and oxidative stress [69]. ...
We are facing an obesity epidemic, and obesity itself and its close companion, type 2 diabetes, are independent risk factors for neurodegeneration. While most medical treatments fail to induce a clinically meaningful improvement in neurodegenerative disorders, lifestyle interventions have emerged in the spotlight. A recently rediscovered approach is intermittent fasting (IF), which, compared to the classic caloric restriction regimens, limits only the time of eating, rather than the number of calories allowed per day. There is already a large amount of evidence from preclinical and clinical studies showing the beneficial effects of IF. In this review, we specifically focus on the effects of IF on brain metabolism. Key molecular players modified during IF and involved in its beneficial central effects (ketone bodies, BDNF, GABA, GH/IGF-1, FGF2, sirtuin-3, mTOR, and gut microbiota) are identified and discussed. Studies suggest that IF induces several molecular and cellular adaptations in neurons, which, overall, enhance cellular stress resistance, synaptic plasticity, and neurogenesis. Still, the absence of guidelines regarding the application of IF to patients hampers its broad utilization in clinical practice, and further studies are needed to improve our knowledge on the different IF protocols and long-term effects of IF on brain metabolism before it can be widely prescribed.
... Brown fats are more metabolically active fat that produces more fuel. Fasting considerably lowers the risk of fatty liver disease and ameliorates insulin resistance (K. A. Varady, 2011). ...
Metabolic syndrome (MetS) is a growing problem worldwide. Gulf countries, being part of the Middle East, have shown a high prevalence of metabolic syndrome. MetS typically reflect the clustering of individual cardiometabolic risk factors including central obesity, elevated fasting plasma glucose, dyslipidemia, and elevated blood pressure. Intermittent fasting (IF) has gained prominence as a promising approach for weight loss and mitigation of metabolic syndrome. This review investigates the effect of current evidence of intermittent fasting on metabolic syndrome. Three databases were used to identify studies between 2010 and 2021 using relevant selected keywords to explore the evidence of intermittent fasting's impact on metabolic syndrome. The article selection was made based on the inclusion and exclusion criteria concerning the participants' characteristics, study design, intervention protocols, and targeted dependent variables. We assessed 834 studies for eligibility and Twenty-one articles were identified and reviewed in our narrative synthesis. Overall, the available evidence suggests that IF is considered effective for losing weight, normalizing blood glucose, reducing lipids, and lowering blood pressure, particularly among obese subjects. Studies are urgently needed especially, randomized controlled trials with a long-term follow-up period of the abovementioned four variables.
... Yet, the sum of weight loss is similar to other traditional caloric restriction strategies. However, changes in body composition and tissue mass are unequal [59,[61][62][63] with a notable tendency for lean mass loss with IF [58,60,61,64]. ...
Optimal cognitive functions are necessary for activities of daily living and self-independence. Cognitive abilities are acquired during early childhood as part of progressive neurodevelopmental milestones; unfortunately, regressive changes can occur as part of physiological aging, or more ominously, pathological diseases, such as Alzheimer’s disease (AD). Cases of AD and its milder subset, mild cognitive impairment (MCI), are rising and would impose a burdensome impact beyond the individual level. Various dietary and nutritional approaches have potential for promising results in managing cognitive deterioration. Glucose is the core source of bioenergy in the body; however, glucose brain metabolism could be affected in aging cells or due to disease development. Ketone bodies are an efficient alternate fuel source that could compensate for the deficient glycolytic metabolism upon their supra-physiologic availability in the blood (ketosis), which, in turn, could promote cognitive benefits and tackle disease progression. In this review, we describe the potential of ketogenic approaches to produce cognitive benefits in healthy individuals, as well as those with MCI and AD. Neurophysiological changes of the cognitive brain in response to ketosis through neuroimaging modalities are also described in this review to provide insight into the ketogenic effect on the brain outside the framework of purely molecular explanations.
... Опубликованы интересные суммарные данные 18 наблюдательных клинических исследований американцев с избыточной массой тела без диабета [9]. Автор анализировал особенности снижения веса при постоянном (ежедневно на 15-60%) и периодическом (один день -Патологическая физиология и экспериментальная терапия. ...
Интервальное голодание (intermittent fasting) - метод профилактики и лечения людей с самой распространенной сегодня патологией: избыточной массой тела и ожирением. Особую актуальность проблеме создает тот факт, что некрасивое и осложняющее жизнь ожирение - маркер расстройства метаболизма, предрасполагающего к развитию многих неинфекционных пандемий современного человечества. Интервальное голодание осуществляется ежесуточным полным отказом от еды на срок не менее 12 часов, - соотношение периодов голодания и приема пищи 12 ч : 12 ч. Увеличение периода голодания, например, 18 ч : 6 ч повышает профилактическую и лечебную эффективность интервального голодания.
Intermittent fasting is a method for prevention and treatment of the currently most common pathology, overweight and obesity. Of particular relevance is the fact that ugly and life-complicating obesity is a marker of metabolic disorders that predispose people to many noninfectious pandemics. The interval fasting is performed by daily complete refraining from food for at least 12 hours with a 12h:12h ratio of fasting and food consumption periods. Increasing the fasting period, for example to 18h:6h, enhances the preventive and therapeutic efficacy of intermittent fasting.
... Many different strategies could be used to make daily energy deficiency, among these strategies, continuous energy restriction (CER) and intermittent energy restriction (IER) are wildly used as pre-contest strategies in physique competitors and Olympic weightlifters. CER requires reducing a daily energy intake relative to bodyweight maintenance requirements; alternatively, IER uses alternating periods of energy restriction with periods of greater energy intake that are sometimes referred to as "refeed" periods or "cheat days" within the fat-loss plan [11,12]. ...
Objective:
To compare the effects of continuous energy restriction (CER) and intermittent energy restriction (IER) in bodyweight loss plan in sedentary individuals with normal bodyweight and explore the influence factors of effect and individual retention.
Methods:
26 participants were recruited in this randomized controlled and double-blinded trial and allocated to CER and IER groups. Bodyweight (BW), body mass index (BMI), and resting metabolic rate (RMR) would be collected before and after a 4-week (28 days) plan which included energy restriction (CER or IER) and moderate-intensity exercise. Daily intake of three major nutrients (protein, carbohydrate, fat) and calories were recorded.
Results:
A significant decrease in BW and BMI were reported within each group. No statistically significant difference in the change of RMR in CERG. No statistically significant difference was reported in the effect between groups, neither as well the intake of total calories, three major nutrients, and individual plan retention. The influence factors of IER and CER are different.
Conclusion:
Both CER and IER are effective and safe energy restriction strategies in the short term. Daily energy intake and physical exercise are important to both IER and CER.
... Whether weight loss rates differ between intermittent and continuous types of energy restriction is still under research, but growing evidence points to equal rates when duration and overall CR are matched (Harvie & Howell, 2017;Trepanowski et al, 2017). Metaanalyses and systematic reviews support this notion (Varady, 2011;Cioffi et al, 2018). Altogether, the body of evidence available so far warrants further direct comparison studies between CR and IF. ...
Age-associated diseases are rising to pandemic proportions, exposing the need for efficient and low-cost methods to tackle these maladies at symptomatic, behavioral, metabolic, and physiological levels. While nutrition and health are closely intertwined, our limited understanding of how diet precisely influences disease often precludes the medical use of specific dietary interventions. Caloric restriction (CR) has approached clinical application as a powerful, yet simple, dietary modulation that extends both life- and healthspan in model organisms and ameliorates various diseases. However, due to psychological and social-behavioral limitations, CR may be challenging to implement into real life. Thus, CR-mimicking interventions have been developed, including intermittent fasting, time-restricted eating, and macronutrient modulation. Nonetheless, possible side effects of CR and alternatives thereof must be carefully considered. We summarize key concepts and differences in these dietary interventions in humans, discuss their molecular effects, and shed light on advantages and disadvantages.
... Sin embargo, la cirugía bariátrica y el uso de algunos medicamentos pueden ocasionar efectos secundarios en mayor grado; por ello, se consideran como primera opción las estrategias relacionadas con la restricción calórica y la actividad física 3,4 . La REC es el método más comúnmente utilizado en la pérdida de peso a través de la dieta, se caracteriza por reducir la ingesta calórica diaria entre un 15-60% con relación a los requerimientos calóricos para mantenimiento de peso corporal, sin modificar la frecuencia de las comidas 5,6 . A pesar de que se ha demostrado que este método de restricción calórica es una estrategia eficaz para la pérdida de peso, algunos pacientes han señalado que es un régimen de alimentación difícil de mantener; es por ello, que algunos pacientes prefieren utilizar el método de REI como una alternativa para la disminución de peso [7][8][9][10] . ...
Introducción: La restricción de energía intermitente (REI) y la restricción de energía continua (REC) son estrategias efectivas en la disminución del peso corporal en adultos. En la REI se limita la ingesta por menos de 24 horas con periodos de restricción energética totales o parciales (75-90%). Son aplicados por lo general de seis a ocho horas entre uno y siete días por semana, seguido de un periodo de alimentación habitual. En la REC se reduce la ingesta entre un 15-60% del requerimiento energético diario. El objetivo de la presente revisión fue comprobar el posible mayor efecto de la REI en la pérdida de peso en comparación con la REC en hombres y mujeres adultos con sobrepeso y obesidad.
Material y métodos: Se realizó una revisión sistemática en la que se incluyeron estudios clínicos; originales; realizados en hombres y mujeres con sobrepeso u obesidad, que se centraron en la pérdida de peso mediante la REI en comparación con la REC en los últimos ocho años (2011-2019). Las bases de datos utilizadas para la búsqueda electrónica fueron PubMed, Cochrane Library y Web of Science. Se obtuvieron 303 artículos, de los cuales únicamente diez cumplieron con los criterios de inclusión para la presente revisión sistemática.
Resultados: Los métodos de REI y de REC utilizados de manera individual, como en combinación entre ellos, facilitan una pérdida de peso corporal de manera similar en hombres y mujeres adultos con sobrepeso y obesidad, incluso en personas con diabetes mellitus tipo 1.
Conclusiones: La pérdida de peso estuvo mediada principalmente por la restricción de energía, la REI no fue superior a la REC como intervención terapéutica, dado que la pérdida de peso parece estar mediada por el nivel de restricción energética y no porque se realice de forma continua o discontinua.
Material y métodos: Se realizó una revisión sistemática en la que se incluyeron estudios clínicos; originales; realizados en hombres y mujeres con sobrepeso u obesidad, que se centraron en la pérdida de peso mediante la REI en comparación con la REC en los últimos ocho años (2011-2019). Las bases de datos utilizadas para la búsqueda electrónica fueron PubMed, Cochrane Library y Web of Science. Se obtuvieron 303 artículos, de los cuales únicamente diez cumplieron con los criterios de inclusión para la presente revisión sistemática.
Resultados: Los métodos de REI y de REC utilizados de manera individual, como en combinación entre ellos, facilitan una pérdida de peso corporal de manera similar en hombres y mujeres adultos con sobrepeso y obesidad, incluso en personas con diabetes mellitus tipo 1.
Conclusiones: La pérdida de peso estuvo mediada principalmente por la restricción de energía, la REI no fue superior a la REC como intervención terapéutica, dado que la pérdida de peso parece estar mediada por el nivel de restricción energética y no porque se realice de forma continua o discontinua.
Dietary sulfur amino acid restriction (SAAR) improves metabolic health in animals, but in humans, SAAR has not been investigated in translational clinical trials. In this study, we investigated the effect of dietary SAAR on body weight, body composition, resting metabolic rate, gene expression profiles in white adipose tissue (WAT), and an extensive blood biomarker profile in 59 humans with overweight and obesity in a double-blind, randomized controlled trial (ClinicalTrials.gov: NCT04701346 ). Participants were randomized to a plant-based diet low (~2 g/d, SAAR) or high (~5.6 g/d, control group) in sulfur amino acids. The diets were provided in full to the participants. After 8 weeks of intervention, SAAR led to a ~20 % greater weight loss compared to controls (β (95 % CI) -1.14 (-2.04, -0.25) kg, p = 0.012). Despite greater weight loss, resting metabolic rate remained similar between groups. Furthermore, SAAR decreased serum leptin, and increased ketone bodies compared to controls. In WAT, 20 genes were upregulated whereas 24 genes were downregulated (FDR < 5 %) in the SAAR group compared to controls. Generally applicable gene set enrichment analyses revealed that processes associated with ribosomes were upregulated, whereas processer related to structural components were downregulated. In conclusion, our study shows that SAAR leads to weight loss and metabolic benefits. Further research SAAR is needed to investigate the therapeutic potential for metabolic conditions in humans.
Objective: The present study aimed to evaluate and compare the effects of intermittent fasting, low carb and hypocaloric diets on weight control, lean and lipid mass and lipid and glycemic profiles in obese volunteers. Methods: This is a randomized clinical trial in which the sample consisted of a 30 individuals group, of both sexes, aged between 18 and 40 years with Body Mass Index (BMI) > 25 kg/m² and with similar organic conditions in which they were divided into 3 groups and submitted to the above mentioned diets for 30 days. Results: The results revealed by anthropometry, bioimpedance and laboratory tests show that when the values in the groups are compared separately, we have significant variables. Conclusion: Thus, the hypocaloric diet showed better results, mainly in weight and BMI (body mass index), which helps to control possible patient comorbidities. And in relation to laboratory tests, the Low carb diet and intermittent fasting had good results with reduced levels of blood glucose, total cholesterol, triglycerides, High-density lipoprotein (HDL), Low-density lipoprotein (LDL) and Very low-density lipoprotein (VLDL).
To explore the mechanism by which intermittent fasting (IF) exerts prolonged effects after discontinuation, we examined mice that had been subjected to 4 cycles of fasting for 72 hours and ad libitum feeding for 96 hours per week (72hIF), followed by 4 weeks of ad libitum feeding, focusing on expression of genes for lipid metabolism in the skeletal muscle and histone acetylation in the promoter region. 72hIF resulted in metabolic remodeling, characterized by enhanced lipid utilization and mitochondrial activation in the muscle. The long-term IF (72hIF) caused stronger metabolic effects than alternate day fasting (24hIF) wherein fasting and refeeding are repeated every 24 hours. Up-regulation of lipid oxidation genes and an increase in oxygen utilization were sustained even at 4 weeks after discontinuation of 72hIF, associated with histone hyperacetylation of the promoter region of uncoupling protein 3 (Ucp3) and carnitine palmitoyl transferase 1b (Cpt1b) genes. An increase in leucine owing to fasting-induced muscle degradation was suggested to lead to the histone acetylation. These findings support the previously unappreciated notion that sustainable promotion of histone acetylation in lipid oxidation genes of the muscle and adipose tissues during and after IF may contribute to sustained metabolic effects of IF.
Previously, narrative reviews have considered the effects of intermittent fasting on appetite. One suggestion is that intermittent fasting attenuates an increase in appetite that typically accompanies weight loss. Here, we conducted the first systematic review and meta-analysis to quantify the effects of intermittent fasting on appetite, when compared to a continuous energy restriction intervention. Five electronic databases and trial registers were searched in February 2021 and February 2022. Abstracts (N = 2800) were screened and 17 randomized controlled trials (RCTs), consisting of a variety of intermittent fasting regimes, met our inclusion criteria. The total number of participants allocated to interventions was 1111 and all RCTs were judged as having either some concerns or a high risk of bias (Cochrane RoB 2.0 tool). Random effects meta-analyses were conducted on change-from-baseline appetite ratings. There was no clear evidence that intermittent fasting affected hunger (WMD = -3.03; 95% CI [-8.13, 2.08]; p = 0.25; N = 13), fullness (WMD = 3.11; 95% CI [-1.46, 7.69]; p = 0.18; N = 10), desire to eat (WMD = -3.89; 95% CI [-12.62, 4.83]; p = 0.38; N = 6), or prospective food consumption (WMD = -2.82; 95% CI [-3.87, 9.03]; p = 0.43; N = 5), differently to continuous energy restriction interventions. Our results suggest that intermittent fasting does not mitigate an increase in our drive to eat that is often associated with continuous energy restriction.
Time-restricted feeding (TRF) and Ramadan fasting (RF) have been recently associated with several health outcomes. However, it is not yet clear if they are superior to existing treatments in terms of glucose metabolism, insulin action, and weight loss. This review aims to summarize the current data on the effects of these regimes on body weight, body composition, and glycemia. An electronic search was conducted in PUBMED and SCOPUS databases up to August 2022. Twenty-four records met the inclusion criteria and underwent a risk-of-bias assessment. The main outcomes were: (a) TRF may result in moderate weight loss in individuals with overweight/obesity; when TRF is combined
with caloric restriction, weight loss is >5% of the initial body weight, (b) 14 h of fasting may be as effective as 16 h in terms of weight loss, and (c) TRF may lead to improved insulin sensitivity and glycemic responses/variability throughout the day in individuals with overweight/obesity. Concerning RF, only two studies were available and thus, conclusions were not drawn. TRF may be an effective nutritional approach for weight loss, and the amelioration of glycemic control and insulin sensitivity in individuals with overweight/obesity. However, more long-term, well-designed studies are needed.
Wasting syndrome (WS) is characterized by clinically important unintentional weight loss >5 % in six to 12 months. This syndrome is responsible for a significant portion of hospitalizations throughout the world and is an important indicator of serious diseases, especially in individuals with 60 years of age or older. The aim of the present study was to investigate WS and associated factors in hospitalized older people. An observational cross-sectional study was developed at a university hospital in Brazil with male and female patients ≥60 years of age. WS was considered in the occurrence of unintentional weight loss of 10 % in 12 months, 7.5 % in six months or >5 % in three months. Data were collected on sociodemographic, clinical, lifestyle, nutritional and biochemical characteristics. This study received approval from the local institutional review board and all participants signed a statement of informed consent. The sample was composed of 178 older people with a mean age of 70.0 ± 8.0 years. The prevalence of WS was 45.5 %. WS was associated with the following clinical variables: conservative CKD (p = 0.007), dysphagia (p = 0.035), dementia (p = 0.017), anorexia (p < 0.001), fatigue (p = 0.001), functional dependence (measured using the Barthel Index) (p = 0.001) and medications that cause malabsorption (p = 0.020); the following nutritional variables: body mass index (p < 0.001), low calf circumference (p < 0.001), low muscle strength (p = 0.001), low muscle mass (p < 0.001) and undernourishment or risk of malnutrition (evaluated using the Mini Nutritional Assessment); and the following biochemical variables: high CRP (p = 0.027), hypoalbuminemia (p = 0.005) and anemia (p < 0.001). The prevalence of WS was high among the hospitalized older people in the present sample and was associated with clinical and biochemical aspects as well as all nutritional variables analyzed. In contrast, lifestyle and sociodemographic characteristics were not associated with wasting syndrome.
A diminuição da prática de atividade física e a difusão da dieta ocidental na população tem contribuído para o desenvolvimento de disfunções metabólicas e doenças associadas, entre elas o excesso de peso. Dentre as intervenções que induzem a restrição calórica, destaca-se o jejum intermitente (JE). Este trabalho analisou a repercussão da prática do JE sobre o desempenho de ratos adultos no labirinto em cruz elevado (LCE). Ratos Wistar adultos foram alimentados com dieta Padrão do Biotério para os grupos controle (C) e experimental (E). O grupo E foi submetido ao JE em dias alternados durante 3 semanas. Os animais foram pesados aos 90 e 111 dias de idade. Ao completarem 111 dias de idade foram submetidos ao teste do LCE por 5 minutos. Foram observadas diferenças significativas no peso corporal do grupo E em relação ao grupo C ao final dos 21 dias do estudo. Quanto ao número de entradas nos braços abertos e braços fechados não foram observadas diferenças significativas entre os grupos estudados. Em relação às categorias comportamentais foi encontrada diferença significativa na autolimpeza para o grupo E. O jejum intermitente altera o peso corporal de ratos adultos, bem como aspectos comportamentais. Palavras – chave: Labirinto em cruz elevado; Jejum intermitente; Restrição calórica; Ansiedade; Ratos.
The scientific community currently expresses a high level of interest in intermittent fasting - periods of voluntary abstinence from energy intake, ranging from several hours to days. Intermittent fasting is clinically relevant and may represent an effective non- pharmacological strategy to improve physical performance and body composition. It has been studied mainly in athletes during the religious period of Ramadan and in people predisposed to decrease body fat without loss of fat-free mass parallel. The purpose of this review is to provide an overview of the impact of intermittent fasting during Ramadan vs. non-Ramadan intermittent fasting in terms of physical performance and body composition. The literature shows some inconsistencies in terms of the interaction between intermittent fasting and physical performance. However, non-Ramadan intermittent fasting is found to be effective in improving maximal aerobic power. Nevertheless, this intervention reduces performance during the repeated sprints over the first few days of intervention. On the other hand, intermittent fasting during Ramadan being the maximum aerobic power and this is more expressive during the second half of this religious period. However, both interventions are manifestly innocuous in terms of muscle strength and anaerobic capacity. With regard to body composition, there is greater consensus. According to available data, both interventions encourage beneficial adaptations at this level. Still, fat loss is more pronounced with intermittent non-Ramadan fasting.
Objective
1. To explore the safety and effectiveness of alternate day fasting in Chinese people. 2. To compare weight loss outcome and safety when using a high protein diet (HP) vs. a normal protein diet (NP) vs. a nutritional meal replacement (MR) on fasting days.
Research Methods & Procedures
This study was a randomized, open, parallel controlled, interventional, exploratory trial, that included a 3-day run-in period and a 28-day intervention period. Adult participants without restriction of body mass index (n = 60) were randomly assigned to three alternative-day fasting (ADF) intervention groups: group HP, group NP and group MR. The primary outcome was weight change from baseline at 28 days.
Results
Overall participants lost an average of 2.53 kg. Mean triglycerides, total cholesterol, and low-density lipoprotein were significantly reduced by 0.10 mmol/L, 0.15 mmol/L, and 0.11 mmol/L, respectively. The mean hunger scale on the first day of fasting was 18.73 at breakfast and 45.25 at dinner. The mean hunger scale on the last day of fasting decreased significantly, to 10.89 at breakfast and 18.93 at dinner. Weight loss of groups HP, NP, and MR were 2.16, 2.63 and 2.94 kg, respectively; groups did not differ significantly (P = 0.841). The most common adverse events were dizziness, heart palpitation and fatigue.
Conclusions
ADF is an effective short-term weight loss strategy that is tolerated by most Chinese participants. We suggest that dietary patterns during fasting days is less important, and that calorie restriction during fasting days should be the focus.
Vücut geliştirme sporunun popülaritesi gün geçtikçe artmaktadır fakat buna karşılık literatüre bakıldığında kanıta dayalı beslenme önerilerinin sayısının oldukça az olduğu görülmektedir. Bu çalışmada literatürde geçen, vücut ge- liştirme sporcuları için verilen kanıta dayalı güncel beslenme önerileri derlenmiştir. Vücut geliştirme sporuyla ilgilenen bireylerde enerji ihtiyacının doğru hesaplanması, vücut ağırlığında azalma sağlamak için temel hedef olmalıdır. Vücut geliştirme sporcularında kas kaybını önlemek için haftalık en fazla %1’lik vücut ağırlığında azalma önerilmektedir. Vücut geliştirme sporcusu için gerekli enerji hesaplaması yapıldıktan sonra, vücut ağırlığında kilogram başına en az 2.3 g/kg/gün protein alımı önerilmektedir. Aynı zamanda her öğünün 0.4-0.5 g/kg protein içermesi önerilmektedir. Günlük enerji gereksiniminin %15-30’unun yağlardan, %20’sinin proteinlerden ve geri kalanın ise karbonhidratlardan gelecek şekilde beslenme programı düzenlenmelidir. Vücut geliştirme sporcuları için ideal öğün sayısında ise özellikle dayanıklılık egzersizleri süresince günlük 3 ile 6 öğün tercih edilmelidir. Yapılan araştırma sonuçlarına göre öğün saatleri ve sıklığının vücut ağırlığında azalma veya yağsız kütleyi korumak için belirgin bir pozitif etkisinin olmadığı görülmüştür. Müsabakalardan birkaç gün önce uygulanan dehidrasyon programı, elektrolit imbalansına sebep olabileceğinden dikkatli olunması gerekmektedir. Müsabakalara hazırlanılan son dönemlerde karbonhidrat alımındaki artışın olumlu etkileri olabilir, bu sebeple karbonhidrat yüklemesi sporcuya uygun olarak yapılmalıdır. Vücut geliştirme sporcularında supleman kullanımıyla ilgili de farklı tartışmalar bulunmaktadır. Kreatin monohidrat, kafein ve beta alanin alımının müsabakalara hazırlanma süresince olumlu etkileri olduğu görülmüştür. Diğer suplemanlarla ilgili daha fazla çalışmaya ihtiyaç olduğu, güncel literatür verileri dahilinde düşünülmektedir. Son olarak, estetik bir spor çeşidi olan vücut geliştirme sporcularında yeme bozuklukları ve vücut algısı bozukluklarının sık görüldüğü unutulmamalıdır.
Caloric restriction is a popular approach to treat obesity and its associated chronic illnesses but is difficult to maintain for a long time. Intermittent fasting is an alternative and easily applicable dietary intervention for caloric restriction. Moreover, intermittent fasting has beneficial effects equivalent to those of caloric restriction in terms of body weight control, improvements in glucose homeostasis and lipid profiles, and anti-inflammatory effects. In this review, the beneficial effects of intermittent fasting are discussed.
Background
The popularity of intermittent fasting (IF) has increased as more and more people are trying to avoid or alleviate obesity and metabolic disease. This study aimed to systematically explore the effects of various IF in humans.
Methods
The randomized controlled trials (RCTs) related to IF versus normal diet (non-intervention diet) or caloric restriction (CR) were retrieved in PubMed, Web of Science, the Cochrane Library database, and Embase. Extraction outcomes included, but not limited to, weight, body mass index (BMI), waist circumference (WC), glucose, and triglyceride (TG).
Results
Contrasting results showed that, participants had lower weight (WMD = 1.10, 95%CI: 0.09–2.12, p = 0.03) and BMI after IF (WMD = 0.38, 95%CI: 0.08–0.68, p = 0.01). The WC of participants in the IF group decreased significantly compared with the normal diet (WMD = 1.02, 95%CI: 0.06–1.99, p = 0.04). IF regulated fat mass (FM) more effectively than normal diet (WMD = 0.74, 95%CI: 0.17–1.31, p = 0.01). The fat-free mass of people after IF was higher (WMD=-0.73, 95%CI: (-1.45)-(-0.02), p = 0.05). There was no difference in blood glucose fluctuation between participants in the after IF and normal diet groups. The results of insulin and HOMA-IR, though, indicated that IF was significantly more beneficial than normal diet (SMD=-0.21, 95%CI: 0.02–0.40, p = 0.03, and WMD = 0.35, 95%CI: 0.04–0.65, p = 0.03, respectively). Cholesterol and TG levels after IF were also lower than after a normal diet (SMD = 0.22, 95%CI: 0.09–0.35, p = 0.001, and SMD = 0.13, 95%CI: 0.00-0.26, p = 0.05, respectively).
Conclusion
IF reduced weight, WC, and FM without affecting lean tissue. IF also could improve insulin resistance and blood lipid conditions compared with non-intervention diets.
Fasting improves metabolic health, but rapid weight gain after fasting might have a negative impact on health. We investigated whether repeated bouts of fasting and refeeding promote accumulation of body fat and protect skeletal muscle as well as liver from wasting during the subsequent exposure to fasting. We compared changes in body composition after the first bout (bout 1) and the eighth bout (bout 8) of 2-day fasting followed by 5-day re-feeding in 22-week-old C57BL/6J male mice. We have also assessed serum IGF-1 and gene expression of proteasome (MurF1, Atrogin-1) and autophagy (p62, LC3b) markers of protein breakdown in skeletal muscles and liver. In contradiction to our expectations, weight- and aged-matched mice showed slightly greater weight loss in bout 8 compared bout 1 of fasting (17.6 ± 2.2 vs. 15.2 ± 2.4 %, n = 10, p < 0.05). Skeletal muscles showed significant upregulation of proteasome and autophagy markers, but only small loss of mass. Liver wasting was significant even though upregulation of autophagy gene expression was modest compared to skeletal muscles. Serum IGF-1 increased and was associated with significant increase in mass of gonadal white adipose tissue. In summary, repeated bouts of fasting and refeeding lead to high serum IGF-1 levels and promote accumulation of body fat, but does not protect from loss of lean body mass during fasting.
To compare body composition determined by bioelectrical impedance (BIA) consumer devices against criterion estimates determined by whole body magnetic resonance imaging (MRI) and dual energy X-ray absorptiometry (DXA) in healthy normal weight, overweight and obese adults.
In 106 adults (54 females, 52 males, age 54.2 +/- 16.1 years, BMI 25.8 +/- 4.4 kg/m(2)) fat mass (FM), skeletal muscle mass (SM), total body bone-free lean mass (TBBLM), and level of visceral fat mass (VF) were estimated by 3 single-frequency bipedal (foot-to-foot) and one tretrapolar BIA device, and compared to body composition measured by MRI and DXA. Bland-Altman and simple linear regression analyses were used to determine agreement between methods.
%FMDXA, SMMRI or TBBLMDXA showed good relative and absolute agreement with two bipolar and one tetrapolar instrument (r(2) = 0.92-0.96; all p < 0.001; mean bias <1.5 %FM and <1 kg SM or TBBLM) and less relative and absolute agreement for another bipolar device (r(2) = 0.82 and 0.84, mean bias approximately 3 %FM and approximately 3 kg SM). The 95% limits of agreement (bias +/- 2 SD) were narrowest for the tetrapolar device (-6.59 to 4.61 %FM and -4.62 to 4.74 kg SM) and widest for bipolar instruments (up to -14.54 to 8.58 %FM and -9.52 to 3.92 kg SM). Systematic biases for %FM were found for all bipedal devices, but not for the tetrapolar instrument.
Because of the lower agreement between foot-to-foot BIA and DXA or MRI for the assessment of body composition in individuals, tetrapolar electrode arrangement should be preferred for individual or public use. Bipolar devices provide accurate results for field studies with group estimation.
In the last few years, polycystic ovary syndrome (PCOS) has deserved major attention because it is linked to the same cluster of events that promote the metabolic syndrome. This review will point out the relationships between fat excess, insulin resistance and the metabolic syndrome. Adipocytes are actually considered as endocrine cells that synthesize and release molecules (adipokines) that play an endocrine/paracrine role, such as adiponectin, atrial natriuretic peptide, leptin, resistin, tumour necrosis factor alpha (TNFalpha). Metabolic syndrome is a chronic low-grade inflammatory condition in which adipokines play a major role. Isolated adipocytes from women with PCOS express higher mRNA concentrations of some adipokines involved in cardiovascular risk and insulin resistance. However, environmental factors and lifestyle play a major role in determining the appearance of the phenotypes of PCOS. In morbid obese women with PCOS, bariatric surgery decreases bodyweight and fat excess and reverses hyperandrogenism and sterility. In lean or overweight women with PCOS, changes in lifestyle in combination with drugs reducing visceral fat and insulin resistance reverse the symptoms and signs of PCOS. Promising treatments for PCOS seem to be insulin sensitizers such as metformin and glitazones.
Maintenance of a body weight 10% above or below that "customary" for lean or obese individuals results in respective increases or decreases in the energy expended in low levels of physical activity (nonresting energy expenditure, NREE). These changes are greater than can be accounted for by the altered body weight or composition and are due mainly to altered skeletal muscle work efficiency at low levels of power generation. We performed biochemical analysis of vastus lateralis muscle needle biopsy samples to determine whether maintenance of an altered body weight was associated with changes in skeletal muscle histomorphology. We found that the maintenance of a 10% reduced body weight was associated with significant declines in glycolytic (phosphofructokinase, PFK) enzyme activity and, in particular, in the ratio of glycolytic to oxidative (cytochrome c oxidase, COX) enzyme activity without significant changes in the activities of enzymes relevant to mitochondrial density, respiratory chain activity, or fuel transport; or in skeletal muscle fiber type or glycogen stores. The fractional change in the ratio of PFK/COX activity in subjects following weight loss was significantly correlated with changes in the systemic respiratory exchange ratio (RER) and measures of mechanical efficiency of skeletal muscle at low workloads (pedaling a bicycle to generate 10 or 25 W of power). Thus, predictable changes in systemic skeletal muscle biochemistry accompany the maintenance of an altered body weight and account for a significant portion of the variance in skeletal muscle work efficiency and fuel utilization at reduced body weight.
The ability of modified alternate-day fasting (ADF; ie, consuming 25% of energy needs on the fast day and ad libitum food intake on the following day) to facilitate weight loss and lower vascular disease risk in obese individuals remains unknown.
This study examined the effects of ADF that is administered under controlled compared with self-implemented conditions on body weight and coronary artery disease (CAD) risk indicators in obese adults.
Sixteen obese subjects (12 women, 4 men) completed a 10-wk trial, which consisted of 3 phases: 1) a 2-wk control phase, 2) a 4-wk weight loss/ADF controlled food intake phase, and 3) a 4-wk weight loss/ADF self-selected food intake phase.
Dietary adherence remained high throughout the controlled food intake phase (days adherent: 86%) and the self-selected food intake phase (days adherent: 89%). The rate of weight loss remained constant during controlled food intake (0.67 +/- 0.1 kg/wk) and self-selected food intake phases (0.68 +/- 0.1 kg/wk). Body weight decreased (P < 0.001) by 5.6 +/- 1.0 kg (5.8 +/- 1.1%) after 8 wk of diet. Percentage body fat decreased (P < 0.01) from 45 +/- 2% to 42 +/- 2%. Total cholesterol, LDL cholesterol, and triacylglycerol concentrations decreased (P < 0.01) by 21 +/- 4%, 25 +/- 10%, and 32 +/- 6%, respectively, after 8 wk of ADF, whereas HDL cholesterol remained unchanged. Systolic blood pressure decreased (P < 0.05) from 124 +/- 5 to 116 +/- 3 mm Hg.
These findings suggest that ADF is a viable diet option to help obese individuals lose weight and decrease CAD risk. This trial was registered at clinicaltrials.gov as UIC-004-2009.
The objective was to investigate in a group of obese subjects the course in skeletal muscle phospholipid (SMPL) fatty acids (FA) during a 24-weeks weight maintenance program, which was preceded by a successful very low calorie dietary intervention (VLCD). Special focus was addressed to SMPL omega-3 FA, which is a lipid entity that influences insulin action.
Nine obese subjects (BMI = 35.7 +/- 1.0 kg/m(2)), who had completed an 8 weeks VLCD (weight-loss = -9.7 +/- 1.6 kg, P < 0.001), had obtained skeletal muscle biopsies (vastus lateralis) before and after a dietician-guided 24-weeks weight-maintenance program (-1.2 +/- 1.5 kg, P = ns). SMPL FA composition was determined by gas liquid chromatography. During the preceding VLCD, insulin sensitivity (HOMA-IR) and glycemic control (HbA1c) improved but no change in SMPL omega-3 FA was observed. During the weight-maintenance program five subjects received the pancreas lipase inhibitor Orlistat 120 mg t.i.d. versus placebo.
HOMA-IR and HbA1c stabilized and SMPL total omega-3 FA, docosahexaenoic acid and ratio of n-3/n-6 polyunsaturated FA increased by 24% (P < 0.01), 35% (P < 0.02) and 26% (P < 0.01), respectively, whereas saturated and monounsaturated FA did not change. Plasma total-cholesterol and LDL-cholesterol, which decreased during the VLCD, reverted to pre-VLCD levels (P < 0.01). Orlistat therapy was associated with weight-loss (P < 0.05), trends for better glycemic control (P = 0.15) and greater increase in SMPL docosahexaenoic acid (P = 0.12) but similar reversal of plasma cholesterols compared to placebo.
The data are consistent with the notion that greater SMPL omega-3 FA obtained during a weight-maintenance program may play a role for preserving insulin sensitivity and glycemic control being generated during a preceding VLCD.
Exercise intensity may affect the selective loss of abdominal adipose tissue.
This study showed whether aerobic exercise intensity affects the loss of abdominal fat and improvement in cardiovascular disease risk factors under conditions of equal energy deficit in women with abdominal obesity.
This was a randomized trial in 112 overweight and obese [body mass index (in kg/m(2)): 25-40; waist circumference >88 cm], postmenopausal women assigned to one of three 20-wk interventions of equal energy deficit: calorie restriction (CR only), CR plus moderate-intensity aerobic exercise (CR + moderate-intensity), or CR plus vigorous-intensity exercise (CR + vigorous-intensity). The diet was a controlled program of underfeeding during which meals were provided at individual calorie levels (approximately 400 kcal/d). Exercise (3 d/wk) involved treadmill walking at an intensity of 45-50% (moderate-intensity) or 70-75% (vigorous-intensity) of heart rate reserve. The primary outcome was abdominal visceral fat volume.
Average weight loss for the 95 women who completed the study was 12.1 kg (+/-4.5 kg) and was not significantly different across groups. Maximal oxygen uptake ( O(2)max) increased more in the CR + vigorous-intensity group than in either of the other groups (P < 0.05). The CR-only group lost relatively more lean mass than did either exercise group (P < 0.05). All groups showed similar decreases in abdominal visceral fat (approximately 25%; P < 0.001 for all). However, changes in visceral fat were inversely related to increases in O(2)max (P < 0.01). Changes in lipids, fasting glucose or insulin, and 2-h glucose and insulin areas during the oral-glucose-tolerance test were similar across treatment groups.
With a similar amount of total weight loss, lean mass is preserved, but there is not a preferential loss of abdominal fat when either moderate- or vigorous-intensity aerobic exercise is performed during caloric restriction. This trial was registered at (ClinicalTrials.gov) as: NCT00664729.
High-protein (HP) diets are often advocated for weight reduction and weight loss maintenance.
The aim was to compare the effect of low-fat, high-carbohydrate (HC) and low-fat, HP ad libitum diets on weight maintenance after weight loss induced by a very low-calorie diet, and on metabolic and cardiovascular risk factors in healthy obese subjects.
Forty-eight subjects completed the study that consisted of an energy restriction period of 5-6 weeks followed by a weight maintenance period of 12 weeks. During weight maintenance subjects received maltodextrin (HC group) or protein (HP group) (casein (HPC subgroup) or whey (HPW subgroup)) supplements (2 x 25 g per day), respectively and consumed a low-fat diet.
Subjects in the HP diet group showed significantly better weight maintenance after weight loss (2.3 kg difference, P=0.04) and fat mass reduction (2.2 kg difference, P=0.02) than subjects in the HC group. Triglyceride (0.6 mM difference, P=0.01) and glucagon (9.6 pg ml(-1) difference, P=0.02) concentrations increased more in the HC diet group, while glucose (0.3 mM difference, P=0.02) concentration increased more in the HP diet group. Changes in total cholesterol, low-density lipoprotein-cholesterol, high-density lipoprotein-cholesterol, insulin, HOMAir index, HbA1c, leptin and adiponectin concentrations did not differ between the diets. No differences were found between the casein- or whey-supplemented HP groups.
These results show that low-fat, high-casein or whey protein weight maintenance diets are more effective for weight control than low-fat, HC diets and do not adversely affect metabolic and cardiovascular risk factors in weight-reduced moderately obese subjects without metabolic or cardiovascular complications.
Mechanisms explaining the decrease in circulatory cholesterol levels after weight loss remain ill defined. The objective was to examine effects of weight loss as achieved through energy restriction upon human in vivo cholesterol biosynthesis. Six subjects (64-77 y, body mass index, 30.3 +/- 3.8 kg/m(2)) were recruited into a two-phase prospective clinical trial. In the first phase, subjects complied with American Heart Association (AHA) Step I diets for 3 mo with no change in their usual energy intake. After this weight-stable phase, subjects consumed an AHA Step I diet with a targeted reduction in energy intake of approximately 1000 kJ/d for 6 mo to achieve negative energy balance leading to weight loss. The incorporation rate of deuterium from body water into erythrocyte membrane free cholesterol over 24 h was utilized as an index of cholesterogenesis at the end of both phases. Subjects' mean weights decreased (P < 0.05) from 89.3 +/- 12.5 kg to 83.2 +/- 11.5 kg (6.8 +/- 2.6% of initial body weight) across phases. Circulating concentrations of total and LDL-cholesterol, and triglycerides also decreased (P < 0. 05) across phases. HDL-cholesterol concentrations were unchanged (P > 0.05). Cholesterol fractional synthetic rate (FSR) after phase 2 (3.04 +/- 1.90%/d) was lower (P < 0.05) than that after phase 1 (8. 42 +/- 3.90%/d). Absolute synthesis rate (ASR) after phase 2 [0.59 +/- 0.38 g/(kg. d)] also was lower (P < 0.05) than that after phase 1 [1.66 +/- 0.84 g/(kg. d)]. These data suggest that, in obese men, energy restriction resulting in even modest weight loss suppresses endogenous cholesterol synthesis, which contributes to a decline in circulating lipid concentrations.
Recent studies support the possibility of estimating abdominal fat using a region of interest (ROI) selected by conventional whole body dual-energy X-ray absorptiometry (DXA). This is an important observation as DXA ROI estimates have some advantages over waist circumference or computed tomography/magnetic resonance imaging (MRI) as a means of assessing visceral adipose tissue (VAT) and adipose tissue distribution. The aim of this study was to evaluate the usefulness of DXA abdominal ROI estimates in assessing VAT among non-obese men.
Observational, cross-sectional study comparing correlations between MRI-measured total VAT and surrogate measures including DXA ROIs. A stepwise multiple regression model was applied to derive a predictive equation with total VAT mass.
Ninety non-obese healthy men between the ages of 18 and 44 y with BMI<30 kg/m(2).
Abdominal adipose tissue and total VAT were measured by whole body MRI; VAT area by single-slice MRI at the L4-5 level; specific DXA ROIs for abdominal regional fat defined as ROI A (L2-4), B (L2-upper iliac), C (lower costal-upper iliac), and D (ROI C excluding spine); and simple anthropometric measures.
Correlations between total VAT and ROIs A (r=0.85) and B (r=0.84) were not significantly different from that of VAT area at L4-5 (r=0.87), but significantly higher (P <0.01) than that of waist circumference (r=0.77). The highest correlations with total abdominal adipose tissue were for DXA ROIs and conventional DXA trunk fat (r=0.95-0.97). A stepwise multiple regression analysis revealed that 86% of the variance in total VAT was predicted by VAT area at L4-5, ROI A, and waist-hip ratio.
DXA ROIs (L2-4, L2-upper iliac) were associated with total VAT as well as MRI-derived VAT area at L4-5 in non-obese men. DXA ROI fat distribution estimates may be useful in the early detection of men with abdominal/visceral obesity.
Prolonged dietary restriction increases the life span in rodents. Some evidence suggests that alternate-day fasting may also prolong the life span.
Our goal was to determine whether alternate-day fasting is a feasible method of dietary restriction in nonobese humans and whether it improves known biomarkers of longevity.
Nonobese subjects (8 men and 8 women) fasted every other day for 22 d. Body weight, body composition, resting metabolic rate (RMR), respiratory quotient (RQ), temperature, fasting serum glucose, insulin, free fatty acids, and ghrelin were assessed at baseline and after 21 d (12-h fast) and 22 d (36-h fast) of alternate-day fasting. Visual analogue scales were used to assess hunger weekly.
Subjects lost 2.5 +/- 0.5% of their initial body weight (P < 0.001) and 4 +/- 1% of their initial fat mass (P < 0.001). Hunger increased on the first day of fasting and remained elevated (P < 0.001). RMR and RQ did not change significantly from baseline to day 21, but RQ decreased on day 22 (P < 0.001), which resulted in an average daily increase in fat oxidation of > or =15 g. Glucose and ghrelin did not change significantly from baseline with alternate-day fasting, whereas fasting insulin decreased 57 +/- 4% (P < 0.001).
Alternate-day fasting was feasible in nonobese subjects, and fat oxidation increased. However, hunger on fasting days did not decrease, perhaps indicating the unlikelihood of continuing this diet for extended periods of time. Adding one small meal on a fasting day may make this approach to dietary restriction more acceptable.
Insulin resistance is currently a major health problem. This may be because of a marked decrease in daily physical activity during recent decades combined with constant food abundance. This lifestyle collides with our genome, which was most likely selected in the late Paleolithic era (50,000-10,000 BC) by criteria that favored survival in an environment characterized by fluctuations between periods of feast and famine. The theory of thrifty genes states that these fluctuations are required for optimal metabolic function. We mimicked the fluctuations in eight healthy young men [25.0 +/- 0.1 yr (mean +/- SE); body mass index: 25.7 +/- 0.4 kg/m(2)] by subjecting them to intermittent fasting every second day for 20 h for 15 days. Euglycemic hyperinsulinemic (40 mU.min(-1).m(-2)) clamps were performed before and after the intervention period. Subjects maintained body weight (86.4 +/- 2.3 kg; coefficient of variation: 0.8 +/- 0.1%). Plasma free fatty acid and beta-hydroxybutyrate concentrations were 347 +/- 18 and 0.06 +/- 0.02 mM, respectively, after overnight fast but increased (P < 0.05) to 423 +/- 86 and 0.10 +/- 0.04 mM after 20-h fasting, confirming that the subjects were fasting. Insulin-mediated whole body glucose uptake rates increased from 6.3 +/- 0.6 to 7.3 +/- 0.3 mg.kg(-1).min(-1) (P = 0.03), and insulin-induced inhibition of adipose tissue lipolysis was more prominent after than before the intervention (P = 0.05). After the 20-h fasting periods, plasma adiponectin was increased compared with the basal levels before and after the intervention (5,922 +/- 991 vs. 3,860 +/- 784 ng/ml, P = 0.02). This experiment is the first in humans to show that intermittent fasting increases insulin-mediated glucose uptake rates, and the findings are compatible with the thrifty gene concept.
Alterations in the intestinal bacterial flora are believed to be contributing factors to many chronic inflammatory and degenerative diseases including rheumatic diseases. While microbiological fecal culture analysis is now increasingly used, little is known about the relationship of changes in intestinal flora, dietary patterns and clinical outcome in specific diseases. To clarify the role of microbiological culture analysis we aimed to evaluate whether in patients with rheumatoid arthritis (RA) or fibromyalgia (FM) a Mediterranean diet or an 8-day fasting period are associated with changes in fecal flora and whether changes in fecal flora are associated with clinical outcome.
During a two-months-period 51 consecutive patients from an Integrative Medicine hospital department with an established diagnosis of RA (n = 16) or FM (n = 35) were included in the study. According to predefined clinical criteria and the subjects' choice the patients received a mostly vegetarian Mediterranean diet (n = 21; mean age 50.9 +/-13.3 y) or participated in an intermittent modified 8-day fasting therapy (n = 30; mean age 53.7 +/- 9.4 y). Quantitative aerob and anaerob bacterial flora, stool pH and concentrations of secretory immunoglobulin A (sIgA) were analysed from stool samples at the beginning, at the end of the 2-week hospital stay and at a 3-months follow-up. Clinical outcome was assessed with the DAS 28 for RA patients and with a disease severity rating scale in FM patients.
We found no significant changes in the fecal bacterial counts following the two dietary interventions within and between groups, nor were significant differences found in the analysis of sIgA and stool ph. Clinical improvement at the end of the hospital stay tended to be greater in fasting vs. non-fasting patients with RA (p = 0.09). Clinical outcome was not related to alterations in the intestinal flora.
Neither Mediterranean diet nor fasting treatments affect the microbiologically assessed intestinal flora and sIgA levels in patients with RA and FM. The impact of dietary interventions on the human intestinal flora and the role of the fecal flora in rheumatic diseases have to be clarified with newer molecular analysis techniques. The potential benefit of fasting treatment in RA and FM should be further tested in randomised trials.
There is debate over the independent and combined effects of dieting and increased physical activity on improving metabolic risk factors (body composition and fat distribution).
The objective of the study was to conduct a randomized, controlled trial (CALERIE) to test the effect of a 25% energy deficit by diet alone or diet plus exercise for 6 months on body composition and fat distribution.
This was a randomized, controlled trial.
The study was conducted at an institutional research center.
Thirty-five of 36 overweight but otherwise healthy participants (16 males, 19 females) completed the study.
Participants were randomized to either control (healthy weight maintenance diet, n = 11), caloric restriction (CR; 25% reduction in energy intake, n = 12), or caloric restriction plus exercise (CR+EX; 12.5% reduction in energy intake + 12.5% increase in exercise energy expenditure, n = 12) for 6 months.
Changes in body composition by dual-energy x-ray absorptiometry and changes in abdominal fat distribution by multislice computed tomography were measured. Results: The calculated energy deficit across the intervention was not different between CR and CR+EX. Participants lost approximately 10% of body weight (CR: - 8.3 +/- 0.8, CR+EX: - 8.1 +/- 0.8 kg, P = 1.00), approximately 24% of fat mass (CR: - 5.8 +/- 0.6, CR+EX: - 6.4 +/- 0.6 kg, P = 0.99), and 27% of abdominal visceral fat (CR: 0.9 +/- 0.2, CR+EX: 0.8 +/- 0.2 kg, P = 1.00). Both whole-body and abdominal fat distribution were not altered by the intervention.
Exercise plays an equivalent role to CR in terms of energy balance; however, it can also improve aerobic fitness, which has other important cardiovascular and metabolic implications.
There remains no consensus about the optimal dietary composition for sustained weight loss.
The objective was to examine the effects of 2 dietary macronutrient patterns with different glycemic loads on adherence to a prescribed regimen of calorie restriction (CR), weight and fat loss, and related variables.
A randomized controlled trial (RCT) of diets with a high glycemic load (HG) or a low glycemic load (LG) at 30% CR was conducted in 34 healthy overweight adults with a mean (+/-SD) age of 35 +/- 6 y and body mass index (kg/m(2)) of 27.6 +/- 1.4. All food was provided for 6 mo in diets controlled for confounding variables, and subjects self-administered the plans for 6 additional months. Primary and secondary outcomes included energy intake measured by doubly labeled water, body weight and fatness, hunger, satiety, and resting metabolic rate.
All groups consumed significantly less energy during CR than at baseline (P < 0.01), but changes in energy intake, body weight, body fat, and resting metabolic rate did not differ significantly between groups. Both groups ate more energy than provided (eg, 21% and 28% CR at 3 mo and 16% and 17% CR at 6 mo with HG and LG, respectively). Percentage weight change at 12 mo was -8.04 +/- 4.1% in the HG group and -7.81 +/- 5.0% in the LG group. There was no effect of dietary composition on changes in hunger, satiety, or satisfaction with the amount and type of provided food during CR.
These findings provide more detailed evidence to suggest that diets differing substantially in glycemic load induce comparable long-term weight loss.
Visceral adipose tissue (VAT) is associated with greater obesity-related metabolic disturbance. Many studies have reported preferential loss of VAT with weight loss.
This systematic review looks for factors associated with preferential loss of VAT relative to subcutaneous abdominal fat (SAT) during weight loss.
Medline and Embase were searched for imaging-based measurements of VAT and subcutaneous abdominal adipose tissue (SAT) before and after weight loss interventions. We examine for factors that influences the percentage change in VAT versus SAT (%deltaV/%deltaS) with weight loss. Linear regression analyses were performed on the complete data set and on subgroups of studies. Factors examined included percentage weight loss, degree of caloric restriction, exercise, initial body mass index (BMI), gender, time of follow-up and baseline VAT/SAT.
There were 61 studies with a total of 98 cohort time points extracted. Percentage weight loss was the only variable that influenced %deltaV/%deltaS (r=-0.29, P=0.005). Modest weight loss generated preferential loss of VAT, but with greater weight loss this effect was attenuated. The method of weight loss was not an influence with one exception. Very-low-calorie diets (VLCDs) provided exceptional short-term (<4 weeks) preferential VAT loss. But this effect was lost by 12-14 weeks.
Visceral adipose tissue is lost preferentially with modest weight loss, but the effect is attenuated with greater weight loss. Acute caloric restriction, using VLCD, produces early preferential loss of VAT. These observations may help to explain the metabolic benefits of modest weight loss.
OBJECTIVE
Treatment of obesity with very low calorie diet (VLCD) is complicated by protein loss. We evaluated the effects of coadministration of GH on protein turnover, substrate metabolism, and body composition in VLCD treated obesity.DESIGN AND PATIENTSFifteen obese women underwent 4 weeks of very low calorie diet (VLCD) in parallel with GH treatment (n = 7) or placebo (n = 8).MEASUREMENTSProtein metabolism and total glucose turnover were isotopically assayed. Plasma concentrations of amino acids were determined by an HPLC system. Estimated rates of lipid and glucose oxidation were obtained by indirect calorimetry. Fat free mass was determined by DEXA-scan.RESULTSProtein breakdown decreased in both groups (tyrosine flux μmol/h): −12% ± 3 (GH) vs. − 9% ± 3 (placebo)). Phenylalanine degradation in relation to phenylalanine concentration decreased by 9% in the GH group, whereas an increase of 8% was observed in the placebo group (P = 0.1). Plasma concentrations of several amino acids were significantly decreased in the placebo group, while urea excretion decreased in the GH group. A decrease in FFM was found in placebo treated patients (2.14% ± 1.9 (GH) vs. − 3.54% ± 1.6 (placebo), P < 0.05). Rates of lipid oxidation tended to be increased by GH treatment (lipid oxidation (mg/minutes): 79.7 ± 5.9 (GH) vs. 64.6 ± 5.9 (placebo), P = 0.1).CONCLUSION
During dietary restriction GH primarily seems to conserve protein by a reduced hepatic degradation of amino acids.
Although a low resting metabolic rate (RMR) has been shown to be a risk factor for future weight gain, little is known about the mechanisms determining its level. We tested the hypothesis that the composition of the fat-free mass (FFM) is a main determinant of RMR. If this hypothesis is true, a regression model including internal organ masses as independent variables should explain a larger fraction of the variance in RMR than is explained using only FFM as a predictor. We measured fat mass by hydrodensitometry, liver and kidney volumes by computed tomography (CT), heart mass by echocardiography, muscle mass by dual-energy x-ray absorptiometry (DEXA), and RMR by calorimetry in 40 subjects. FFM and fat mass explained 83% of the variability in RMR (standard error of the estimate [SEE], 420 kJ/d) in a multiple regression analysis. Combinations of organ and muscle masses performed as well as but not better than stepwise multiple regression models. The fact that the composition of the lean mass could not improve the prediction of RMR in comparison to the traditional FFM-fat mass model suggests that the weight of internal organs is not a main determinant of RMR. This may indicate that the variability in RMR is associated with variation in energy expenditure per kilogram of tissue of the individual organs.
The purpose was to investigate a possible levelling off in the obesity epidemic, by systematically reviewing literature and web-based sources. Eligible studies and data sources were required to have at least two measures of obesity prevalence since 1999. A literature and Internet search resulted in 52 studies from 25 different countries. The findings supported an overall levelling off of the epidemic in children and adolescents from Australia, Europe, Japan and the USA. In adults, stability was found in the USA, while increases were still observed in some European and Asian countries. Some evidence for heterogeneity in the obesity trends across socioeconomic status (SES) groups was found. The levelling off was less evident in the lower-SES groups. No obvious differences between genders were identified. We discussed potential explanations for a levelling off and the utility of investigating obesity trends to identify the driving forces behind the epidemic. It is important to emphasize that the levelling off is not tantamount to calling off the epidemic. Additionally, it is worthwhile to keep in mind that previous stable phases have been followed by further increases in the prevalence of obesity. Therefore, research into the causes, prevention and treatment of obesity should remain a priority.
Calorie restriction (CR) is the only paradigm that has consistently increased lifespan in a wide variety of model organisms. Many hypotheses have been proposed as the underlying mechanism, including a reduction in body size and adiposity, which is commonly observed in calorie-restricted animals. This has led to investigations as to whether similar changes in body composition produced by increasing energy expenditure via exercise can replace or enhance the benefits of reducing energy intake. The goal of this chapter is to review and discuss the evidence regarding exercise as a CR mimetic for healthy aging and longevity. In rodents, the data clearly show that exercise, regardless of body weight changes, can improve health and survival, but unlike CR, fails to extend lifespan. In humans, short-term weight loss studies show that exercise and CR produce similar improvements in disease risk factors and biomarkers of aging, while some parameters clearly benefit more with exercise. Epidemiologic evidence in humans supports exercise as a strategy to reduce the risk of morbidity and mortality, but not to extend lifespan. It is unknown whether CR can extend human lifespan, but the metabolic profile of humans engaged in long-term CR shares many similarities with calorie restricted rodents and nonhuman primates. In conclusion, like CR, exercise can limit weight gain and adiposity, but only CR can extend lifespan. Therefore, in rodents, the ability of CR to slow aging is apparently more dependent on decreasing nutrient flux, rather than changes in energy balance and body composition.
In this review, we have analyzed the role of visceral obesity in the occurrence of metabolic syndrome (MetS). MetS is a common metabolic disorder that has been related recently to the increasing prevalence of obesity. The disorder is defined in various ways, but in the near future a new definition(s) should be applicable worldwide. The pathophysiology has been largely attributed, in the past years, to insulin resistance, although several epidemiological and pathophysiological data now indicate visceral obesity as a main factor in the occurrence of all the components of MetS. In view of this, relationships among visceral obesity, free fatty acids, dyslipidemia and insulin resistance have been reported. In addition, the effects of some adipocytokines and other proinflammatory factors produced by fat accumulation on the occurrence of MetS have been also emphasized. Accordingly, the "hypoadiponectinemia hypothesis" has been proposed as the most interesting to explain the pathophysiology of MetS. The epidemiologic, pathophysiologic and clinical data reported seem to indicate that MetS might be considered a fatal consequence of visceral obesity.
Decreasing energy intake relative to energy expenditure is the indisputable tenet of weight loss. In addition to caloric restriction modification of the type of dietary fat may provide further benefits. The aim of the present study was to examine the effect of energy restriction alone and with dietary fat modification on weight loss and adiposity, as well as on risk factors for obesity related disease.
One-hundred and fifty overweight men and women were randomized into a 3month controlled trial with four low fat (30% energy) dietary arms: (1) isocaloric (LF); (2) isocaloric with 10% polyunsaturated fatty acids (LF-PUFA); (3) low calorie (LF-LC) (-2MJ); (4) low calorie with 10% PUFA (LF-PUFA-LC). Primary outcomes were changes in body weight and body fat and secondary outcomes were changes in fasting levels of leptin, insulin, glucose, lipids and erythrocyte fatty acids. Changes in dietary intake were assessed using 3day food records. One-hundred and twenty-two participants entered the study and 95 completed the study. All groups lost weight and body fat (P<0.0001 time effect for both), but the LC groups lost more weight (P=0.026 for diet effect). All groups reduced total cholesterol levels (P<0.0001 time effect and P=0.017 intervention effect), but the LC and PUFA groups were better at reducing triacylglycerol levels (P=0.056 diet effect). HDL increased with LF-LC and LF-PUFA but not with LF-PUFA-LC (0.042 diet effect). The LF and LF-LC groups reported greater dietary fat reductions than the two PUFA groups (P=0.043).
Energy restriction has the most potent effect on weight loss and lipids, but fat modification is also beneficial when energy restriction is more modest.
Population aging is progressing rapidly in many industrialized countries. The United States population aged 65 and over is expected to double in size within the next 25 years. In sedentary people eating Western diets aging is associated with the development of serious chronic diseases, including type 2 diabetes mellitus, cancer and cardiovascular diseases. About 80% of adults over 65 years of age have at least one chronic disease, and 50% have at least two chronic diseases. These chronic diseases are the most important cause of illness and mortality burden, and they have become the leading driver of healthcare costs, constituting an important burden for our society. Data from epidemiological studies and clinical trials indicate that many age-associated chronic diseases can be prevented, and even reversed, with the implementation of healthy lifestyle interventions. Several recent studies suggest that more drastic interventions (i.e. calorie restriction without malnutrition and moderate protein restriction with adequate nutrition) may have additional beneficial effects on several metabolic and hormonal factors that are implicated in the biology of aging itself. Additional studies are needed to understand the complex interactions of factors that regulate aging and age-associated chronic disease.
Weight loss using low-calorie diets produces variable results, presumably due to a wide range of energy deficits and low-dietary adherence.
Our objective was to quantify the relationship between dietary adherence, weight loss, and severity of caloric restriction.
Participants were randomized to diet only, diet-endurance training, or diet-resistance training until body mass index (BMI) was less than 25 kg/m(2).
Healthy overweight (BMI 27-30) premenopausal women (n = 141) were included in the study. Interventions: An 800-kcal/d(-1) diet was provided, and the exercise groups were engaged in three sessions per week.
Dietary adherence, calculated from total energy expenditure determined by doubly labeled water measurements and dual-energy x-ray absorptiometry body composition changes, and degree of caloric restriction were determined.
All groups had similar weight loss (approximately 12.1 +/- 2.5 kg) and length of time to reach target BMI (approximately 158 +/- 70 d). Caloric restriction averaged 59 +/- 9%, and adherence to diet was 73 +/- 34%. Adherence to diet was inversely associated to days to reach target BMI (r = -0.687; P < 0.01) and caloric restriction (r = -0.349; P < 0.01). Association between adherence to diet and percent weight lost as fat was positive for the diet-endurance training (r = 0.364; P < 0.05) but negatively correlated for the diet-only group (r = -0.387; P < 0.05).
Dietary adherence is strongly associated with rates of weight loss and adversely affected by the severity of caloric restriction. Weight loss programs should consider moderate caloric restriction relative to estimates of energy requirements, rather than generic low-calorie diets.
We determined the effects of acute and chronic calorie restriction with either a low-fat, high-carbohydrate (HC) diet or a low-carbohydrate (LC) diet on hepatic and skeletal muscle insulin sensitivity.
Twenty-two obese subjects (body mass index, 36.5 +/- 0.8 kg/m2) were randomized to an HC (>180 g/day) or LC (<50 g/day) energy-deficit diet. A euglycemic-hyperinsulinemic clamp, muscle biopsy specimens, and magnetic resonance spectroscopy were used to determine insulin action, cellular insulin signaling, and intrahepatic triglyceride (IHTG) content before, after 48 hours, and after approximately 11 weeks (7% weight loss) of diet therapy.
At 48 hours, IHTG content decreased more in the LC than the HC diet group (29.6% +/- 4.8% vs 8.9% +/- 1.4%; P < .05) but was similar in both groups after 7% weight loss (LC diet, 38.0% +/- 4.5%; HC diet, 44.5% +/- 13.5%). Basal glucose production rate decreased more in the LC than the HC diet group at 48 hours (23.4% +/- 2.2% vs 7.2% +/- 1.4%; P < .05) and after 7% weight loss (20.0% +/- 2.4% vs 7.9% +/- 1.2%; P < .05). Insulin-mediated glucose uptake did not change at 48 hours but increased similarly in both groups after 7% weight loss (48.4% +/- 14.3%; P < .05). In both groups, insulin-stimulated phosphorylation of c-Jun-N-terminal kinase decreased by 29% +/- 13% and phosphorylation of Akt and insulin receptor substrate 1 increased by 35% +/- 9% and 36% +/- 9%, respectively, after 7% weight loss (all P < .05).
Moderate calorie restriction causes temporal changes in liver and skeletal muscle metabolism; 48 hours of calorie restriction affects the liver (IHTG content, hepatic insulin sensitivity, and glucose production), whereas moderate weight loss affects muscle (insulin-mediated glucose uptake and insulin signaling).
Little is known about the relative efficacy of high-protein vs. conventional diet plans that include partial meal replacements on body fat loss in obese subjects with metabolic syndrome.
We aimed to evaluate the efficacy of two low-calorie diets with partial meal replacement plans-a high-protein plan (HP) and a nutritionally balanced conventional (C) plan-on reducing obesity in obese subjects with metabolic syndrome.
In a 12-week, double-blind study, we randomised 75 participants to either the HP- or the C-plan group. We recorded key metrics at 0 and 12 weeks.
The overall mean weight loss was 5 kg in the HP-plan group and 4.9 kg in the C-plan group (p = 0.72). Truncal fat mass decreased 1.6 kg in the HP-plan group (p < 0.05) and 1.5 kg in the C-plan group (p < 0.05), while whole body fat mass decreased 2.5 kg in the HP-plan group (p < 0.05) and 2.3 kg in the C-plan group (p < 0.05). Between-group losses did not differ significantly for truncal (p = 0.52) or whole body (p = 0.77) fat mass. Among subjects with > or = 70% dietary compliance, however, truncal and whole body fat mass decreased more in the HP-plan group (Delta 2.2 kg and Delta 3.5 kg respectively) than in the C-plan group (Delta 1.3 kg and Delta 2.3 [corrected] kg respectively) (p < 0.05).
The HP- and C-plans had a similar effect on weight and abdominal fat reduction, but the HP-plan was more effective in reducing body fat among compliant subjects.
Percent body fat increases with age and is often accompanied by a loss in muscle mass, strength, and energy expenditure. The effects of 16 wk of resistive training (RT) alone or with weight loss (RTWL) on strength (isokinetic dynamometer), body composition (dual-energy X-ray absorptiometry), resting metabolic rate (RMR) (indirect calorimetry), and sympathetic nervous system activity (catecholamines) were examined in 15 postmenopausal women (50-69 yr). RT resulted in significant improvements in upper and lower body strength in both groups (P < 0.01). The nonobese women in the RT group (n = 8) did not change their body weight or fat mass with training. In the obese RTWL group (n = 7), body weight, fat mass, and percent body fat were significantly decreased (P < 0.001). Fat-free mass and RMR significantly increased with training in both groups combined (P < 0.05). There were no significant changes in resting arterialized plasma norepinephrine or epinephrine levels in either group with training. RT increases strength with and without weight loss. Furthermore, RT and RTWL increase fat-free mass and RMR and decrease percent fat in postmenopausal women. Thus, RT may be a valuable component of an integrated weight management program in postmenopausal women.
To compare two different very low calorie diet (VLCD)-based weight maintenance strategies.
A randomized 2-year clinical trial performed at the Department of Body Composition and Metabolism, Sahlgrenska University Hospital, Sweden.
A total of 334 patients, body mass index (BMI) >30 kg m-2, aged 18-60 years.
All the patients started with 16 VLCD weeks. Subjects in the intermittent group were then scheduled to use VLCD for 2 weeks every third month, whilst patients in the on-demand group were instructed to use VLCD whenever their body weight passed an individualized cut-off level. Irrespective of the treatment group, all the subjects were recommended a hypocaloric diet during VLCD-free periods.
Changes in body weight, body composition, anthropometric variables and cardiovascular risk factors.
Completers in both groups maintained highly significant weight losses after 2 years: 7.0 +/- 11.0 kg (6.2 +/- 9.5%) in the intermittent group and 9.1 +/- 9.7 kg (7.7 +/- 8.1%) in the on-demand group (P < 0.001, ns between groups). Male completers in the on-demand group lost significantly more weight than men in the intermittent group, 14.5 +/- 11.0 kg vs. 4.0 +/- 10.5 kg, respectively (P < 0.01). Most cardiovascular risk factors improved during the first year, whilst anthropometric measures, insulin, HDL- and LDL-cholesterol were also significantly improved after 2 years of treatment.
Clinically significant weight reductions were achieved after 2 years of VLCD-based treatment. The structure of VLCD treatment during the maintenance phase did not affect weight loss in the total study population, whilst male subjects might benefit from the VLCD on-demand strategy.