ArticleLiterature Review

Intermittent versus daily calorie restriction: Which diet regimen is more effective for weight loss?

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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.

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... Additionally, the study aimed to investigate the effects of intermittent fasting without energy restriction on the body composition. The current evidence on the effect of intermittent fasting compared with continuous energy restriction on the body composition is not clear and provides controversial results [5,18,31,32,10,[33][34][35]. ...
... This view is supported by the finding in some studies that intermittent fasting leads to a greater loss of adipose tissue [18], while helping to protect the muscle mass [31]. Better maintenance of the fat free mass in response to fasting was found in the weight reduction compared with daily energy restriction [32]. In fact, starvation triggers numerous hormonal adaptations, such as an increase in the serum growth hormone [36], which stimulates lipolysis, increases fat utilization and protein retention [37]. ...
... [38]. Another reason why the protective adaptive response to the fasting state [32,36,37] did not show a statistically significantly greater loss of adipose tissue, as was the case in other studies, could be the presence of fatigue. Its most frequent presence was found in the participants with the intermittent fasting with energy restriction, IG1 (51.9 %; p=0.0473), which may have contributed to the reduced spontaneous physical activity. ...
... IER has been shown to be effective at reducing weight in normal weight and overweight/obese men, women, adolescents, and children. Moreover, IER has been found to improve insulin sensitivity, vital for diabetes prevention [19], and positively affect cardiovascular health by reducing blood pressure and improving lipid profiles [20]. It also demonstrates potential cognitive benefits and might influence lifespan [21]. ...
... IER is emerging as an alternative strategy and is showing effectiveness in weight loss [53]. Studies such as Harvie et al. (2013) [54], Ash et al. (2003) [55], and Varady et al. (2011) [20] showed that IER can lead to significant weight loss, averaging 0.2-0.8 kg/week, comparable to DER [56]. ...
... IER is emerging as an alternative strategy and is showing effectiveness in weight loss [53]. Studies such as Harvie et al. (2013) [54], Ash et al. (2003) [55], and Varady et al. (2011) [20] showed that IER can lead to significant weight loss, averaging 0.2-0.8 kg/week, comparable to DER [56]. ...
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Obesity in the United States and Western countries represents a major health challenge associated with an increased risk of metabolic diseases, including cardiovascular disease, hypertension, diabetes, and certain cancers. Our past work revealed a more pronounced obesity–cancer link in certain ethnic groups, motivating us to develop a tailored dietary intervention called the Healthy Diet and Lifestyle 2 (HDLS2). The study protocol is described herein for this randomized six-month trial examining the effects of intermittent energy restriction (5:2 Diet) plus the Mediterranean dietary pattern (IER + MED) on visceral adipose tissue (VAT), liver fat, and metabolic biomarkers, compared to a standard MED with daily energy restriction (DER + MED), in a diverse participant group. Using MRI and DXA scans for body composition analysis, as well as metabolic profiling, this research aims to contribute to nutritional guidelines and strategies for visceral obesity reduction. The potential benefits of IER + MED, particularly regarding VAT reduction and metabolic health improvement, could be pivotal in mitigating the obesity epidemic and its metabolic sequelae. The ongoing study will provide essential insights into the efficacy of these energy restriction approaches across varied racial/ethnic backgrounds, addressing an urgent need in nutrition and metabolic health research. Registered Trial, National Institutes of Health, ClinicalTrials.gov (NCT05132686).
... The conventional approach to weight loss involves continuous energy restriction (CER), in which energy intake is restricted to below weightmaintenance requirements over a continuous period of active weight loss effort. Such regimens typically consist of reducing daily energy intake by 15% to 60% [1]. Although CER is, on average, an effective weight loss strategy, there is significant interindividual variability reflecting individual challenges in adhering to the prescribed energy restriction [2][3][4]. ...
... In these reviews, the IER regimens varied across studies, making it difficult to compare the effectiveness of different dietary regimens. However, the two most common and widely studied intermittent regimens, i.e., alternate day fasting and the 5:2 diet, lead to weight loss that is not different from that achieved with CER [1,9,10]. ...
... Although this definition was chosen to be specifically different than intermittent dieting within a 1-week period (e.g., the 5:2 diet), the overall conclusions are largely similar [1,9,10]. Another systematic review investigated similar intermittent intervals of ≥7 days but operationalized this differently, i.e., with no limitations on the energy restriction period relative to the pause period, and also found comparable weight loss with CER [31]. ...
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Objective The objective of this study was to investigate whether pausing a weight loss program for a defined period of time could enhance weight loss and reduce attrition. Methods Five databases and two trial registries were searched from inception to July 2023. Randomized‐controlled trials of adults with overweight and/or obesity were included if they compared planned‐pause interventions with continuous energy restriction (CER), usual care, or a minimal intervention. To be included, the weight loss intervention must have incorporated a pause of at least 1 week. Pooled mean differences for weight change and risk ratios for attrition were calculated using random‐effects meta‐analyses. Results Nine intervention arms ( N = 796 participants, 77% female) were included. Pooled results did not detect a significant difference in weight change between planned pauses and CER interventions at the end of the active intervention at a median 26 weeks (planned pauses vs. CER mean: −7.09 vs. −7.0 kg; mean difference: −0.09 kg; 95% CI: −1.10 to 0.93) or at final follow‐up at a median 52 weeks (planned pauses vs. CER mean: −6.91 vs. −6.19 kg; mean difference: −0.72 kg; 95% CI: −2.92 to 1.48). There was no difference in attrition between planned pauses and CER interventions at the end of the active intervention (risk ratio: 1.20, 95% CI: 0.82 to 1.75) or at final follow‐up (risk ratio: 1.04, 95% CI: 0.89 to 1.22). Conclusions Planned pauses were consistently found to be no more or less effective than CER for weight loss or attrition.
... Recently, studies have indicated that IF can improve diet adherence in obese participants [12]. Furthermore, IF is a viable alternative to prolonged calorie restriction and offers comparable benefits in terms of weight management and chronic disease management in overweight and obese individuals [13]. ...
... Our results suggest that different fasting intervention protocols are not associated with a group effect on the BMI. The results of the EDIF trial partly differ from those reported by Varady [13], where an ADF fasting method or daily calorie restriction (between 15% and 60% of the usual daily calorie intake) was conducted. In this case, the overall weight loss in overweight or obese individuals was similar between the groups of each dietary pattern. ...
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The effects of intermittent fasting (IF) on health promotion in the healthy population remain controversial. Therefore, our study aimed to analyse the efficacy and feasibility of different IF protocols and evaluated the effects within a cohort with a controlled-run in phase on the body mass index (BMI) as the primary outcome, the body composition, and metabolic and haematological markers in healthy participants. A total of 25 individuals were randomised into three fasting groups: 16/8 fasting (n = 11), 20/4 fasting (n = 6), and alternate-day fasting (ADF, n = 8). Assessments were conducted at baseline (visit 1), after a four-week controlled-run in phase (visit 2), and after eight weeks of fasting (visit 3). Both the BMI (p = 0.01) and bodyweight (p = 0.01) were significantly reduced in the ADF group, which was not seen in the 16/8 and 20/4 groups (p > 0.05). Adherence was different but not statistically among the groups (16/8: 84.5 ± 23.0%; 20/4: 92.7 ± 9.5%; and ADF: 78.1 ± 33.5%, p = 0.57). Based on our obtained results, the data suggest that some fasting interventions might be promising for metabolic health. However, adherence to the specific fasting protocols remains challenging even for the healthy population.
... However, without a dietary intervention combined with Ex, it is not as effective for weight loss [50]. Dietary energy restriction, that reduces energy intake by 15 to 60%, or IF, are more effective strategies for weight loss [47,51], with a potential downside in a reduction of fat free mass when not combined with Ex [51]. Our findings support the recommendation of combined protocols which is similar to an earlier study, despite the difference in the type of dietary interventions adopted [30,52,53]. ...
... However, without a dietary intervention combined with Ex, it is not as effective for weight loss [50]. Dietary energy restriction, that reduces energy intake by 15 to 60%, or IF, are more effective strategies for weight loss [47,51], with a potential downside in a reduction of fat free mass when not combined with Ex [51]. Our findings support the recommendation of combined protocols which is similar to an earlier study, despite the difference in the type of dietary interventions adopted [30,52,53]. ...
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Introduction and aim Exercise training (Ex) and intermittent fasting (IF) are effective for improving body composition and cardiometabolic health overweight and obese adults, but whether combining Ex and IF induces additive or synergistic effects is less well established. We therefore, performed a systematic review and meta-analysis to compare the combined versus independent effects of Ex and IF on body composition and cardiometabolic health in adults. Method An electronic search was conducted in three main online databases including PubMed, Web of Science, and Scopus, from inception to March 9, 2023 for studies involving Ex plus IF trials versus standalone Ex and/or IF interventions in adults. Interventions had a duration of ≥ 2 weeks. Standardized (SMD) or weighted mean differences (WMD) and 95% confidence intervals were calculated in order to compare effects on body weight, body mass index (BMI), body fat lean body mass (LBM), visceral fat, and waist circumference. For cardiometabolic health, outcomes included fasting glucose, insulin, total cholesterol (TC), low-density lipoprotein cholesterol (LDL), triglycerides (TG), high-density lipoprotein cholesterol (HDL), systolic (SBP) and diastolic (DBP) blood pressure, and VO2max/peak. Results Ex plus IF decreased body weight [WMD: -3.03 kg (95% CI: -3.44 to -2.61), p = 0.001], BMI [WMD: -1.12 kg.m² (95% CI: -1.28 to -0.95), p = 0.001], body fat [SMD: -0.72 (95% CI: -1.23 to -0.21), p = 0.005], visceral fat [SMD: -0.34 (95% CI: -0.63 to -0.05), p = 0.01], and waist circumference [WMD: -2.63 cm (95% CI: -4.16 to -1.11), p = 0.001] more than Ex alone. However, changes in body composition and cardiometabolic health markers were not significantly different for Ex plus IF when compared with IF alone, with the exception of VO2max/peak [SMD: 0.55 (95% CI: 0.14 to 0.97), p = 0.009]. Conclusion We demonstrate that a combination of Ex and IF produces superior changes in body composition, but not in markers of cardiometabolic health when compared with Ex or IF alone. Ex plus IF could therefore be effective for weight and fat loss but has no additive or synergistic effects for other cardiometabolic health markers.
... 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. ...
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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.
... Proteomic and metabolomic insights into MADF's renal protection in diabetic kidney disease insulin resistance lowers postprandial glucose levels, and improves blood pressure and lipid levels, implying that intermittent fasting affects metabolic improvement and cardiovascular protection [26][27][28]. Thus, intermittent fasting is favored as an alternative to calorie restriction and may be a practical dietary approach for improving metabolic syndrome and diabetes. ...
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Background Diabetic kidney disease (DKD) is a leading cause of chronic kidney disease, and while lifestyle interventions like intermittent fasting have shown promise in treating diabetes, the impact of modified alternate-day fasting (MADF) on DKD is not well understood. This study aimed to explore MADF’s effects on DKD in db/db mice, a model for the condition, and to investigate its underlying mechanisms. Methods We implemented an MADF regimen in db/db mice on a high-fat diet, measuring blood glucose, body weight, and renal function at various times. After the intervention, we analyzed the proteome and metabolome of renal tissues. Results MADF was found to reduce hyperglycemia and slow the pathological progression of DKD in the mice. Proteomic analysis identified 165 proteins that increased and 196 that decreased in the kidneys of db/db mice compared to controls. MADF intervention led to a decrease in 26 of the increased proteins and an increase in 18 of the decreased ones. Notably, many of these proteins, including cathepsin S (CTSS), were related to lysosomes, suggesting a role in renal protection. Metabolomic profiling revealed changes in metabolites associated with inflammation, such as prostaglandin A1, which was downregulated in db/db mice and upregulated with MADF. Western blotting, immunohistochemistry, and immunofluorescence staining confirmed the expression changes of CTSS observed in the proteomic data. Additionally, CTSS expression was found to increase in renal cells exposed to high glucose and palmitic acid. Conclusion MADF appears to mitigate the progression of DKD, with proteomic evidence pointing to lysosome-related proteins like CTSS as potential mediators of its renal protective effects. These findings indicate that MADF and the inhibition of CTSS could be considered as novel therapeutic strategies for DKD treatment.
... Proses pembakaran lemak akan berlaku dengan lebih baik sewaktu seseorang berpuasa. Maka dengan ini puasa akan dapat membantu mengurangkan kadar lemak dalam badan untuk menghasilkan tenaga dan seterusnya dapat menurunkan berat badan seseorang (Varady, 2011). ...
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Fasting is a traditional practice observed worldwide with various objectives, including religious, health, and spiritual purposes. This study discusses the effects of fasting on physical and mental health, with an emphasis on continuous fasting such as Ramadan fasting, voluntary fasting, and intermittent fasting (IF). Periodic fasting practices can assist in achieving healthy weight loss. Consistently maintaining a controlled body weight can reduce the strain on the heart and lower the risk of heart disease. Fasting can help regulate blood pressure, as during fasting, the body tends to maintain electrolyte balance in the blood, potentially reducing the risk of hypertension or high blood pressure. Fasting also has the potential to improve blood lipid profiles, including reducing LDL cholesterol (bad cholesterol) levels and increasing HDL cholesterol (good cholesterol) levels. This aids in reducing the risk of atherosclerosis, where fats accumulate in the heart's arteries. Fasting can enhance insulin sensitivity, aiding in blood sugar control and potentially reducing the risk of metabolic diseases like diabetes and heart disease. Additionally, fasting provides the digestive system with an opportunity to rest and facilitates the body's natural detoxification processes. This research is carried out using qualitative methods to investigate the fasting traditions endorsed by Islam, as well as the practice of IF, and their impact on human health. The findings indicate that fasting has significant positive effects on both physical and mental health. Hence, besides observing fasting as an expression of obedience to the directives of Allah and His Messenger, it can also serve as a crucial method for nurturing and improving the overall well-being of individuals.
... Caloric restriction (CR) is a nutritional intervention whereby energy intake is reduced by 15-60% of daily energy, and has been the most common approach for weight reduction described in the research literature. In this large body of evidence, clinical effects on several cardiometabolic risk factors have been reported to vary according to patient health status [27][28][29][30][31]. The potential beneficial role of CR for improving liver function and lowering liver fat content is also known [32][33][34]. ...
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Background Intermittent fasting (IF) can be an effective dietary therapy for weight loss and improving cardiometabolic health. However, there is scant evidence regarding the role of IF on indicators of liver function, particularly in adults with metabolic disorders. Therefore, we performed a systematic review and meta-analysis to investigate the effects of IF on liver function in adults with metabolic disorders. Methods Three primary electronic databases including PubMed, Web of Science, and Scopus, were searched from inception to September 2024 to identify original studies that used IF interventions with or without control groups in adults with metabolic disorders. Inclusion criteria were (1) studies of human participants with metabolic diseases, (2) interventions that evaluated the effects of IF, (3) with or without a control group, and (4) measured liver fat, liver steatosis, liver fibrosis, or liver enzymes, including alanine aminotransferase (ALT) and aspartate aminotransferase (AST) as primary outcomes. Standardized mean differences (SMD) and 95% confidence intervals were calculated using random effects models. Heterogeneity was assessed using the Cochran’s Q statistic and I-squared statistic (I²). Publication bias was assessed using the visual inspection of funnel plots and Egger’s tests. The risk of bias was assessed using the PEDro scale and the NIH quality assessment tool. Results A total 21 studies involving 1,226 participants with metabolic disorders were included in the meta-analysis. Overall, IF effectively decreased liver fat with a large effect size [SMD: -1.22 (95% CI: -1.63 to -0.80), p = 0.001], liver steatosis with a medium effect size [SMD: -0.73 (95% CI: -1.12 to -0.35), p = 0.001], ALT with a small effect size [SMD: -0.44 (95% CI: -0.58 to -0.30), p = 0.001], and AST with a small effect size [SMD: -0.30 (95% CI: -0.49 to -0.11), p = 0.001], but not liver fibrosis [SMD: -0.28 (95% CI: -0.59 to 0.02), p = 0.07]. Subgroup analyses showed that IF decreased liver fat and ALT significantly, independent of IF mode, participant age, health status, weight status, and intervention duration. IF significantly decreased liver fibrosis in those with obesity; and decreased AST following 5:2 diets, in middle-aged adults, adults with obesity, and regardless of health status or intervention duration. Conclusions IF seems to be an effective dietary therapy for improving liver function in adults with metabolic disorders, and many of liver function-related benefits occur regardless of IF mode, intervention duration, or participant health status. Limitations Significant heterogeneity, small numbers of studies and inclusion of non-randomized trials or single-group pre-post trials were the main limitation of our meta-analysis. Further randomized clinical trials are needed to elucidate the effects of IF on liver function in adults with metabolic disorders.
... A meta-analysis showed that green tea, which was also a popular tool for weight reduction, had similar small beneficial effects on both weight loss and maintenance [72]. This means that calorie restriction often causes between 5-10% weight loss in 6 months compared to that achieved from tea alone [73]. The study highlighted that exercise programs resulted in as much weight loss as those involving the consumption of teas when assessed independently, but such combinations improved the ability of someone to shed some pounds [74]. ...
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Purple tea (Camellia sinensis var. assamica) is a distinct variety of Camellia sinensis known for its bioactive compounds, including caffeine, catechins, and a unique compound called 1,2-di-Galloyl-4,6-Hexahydroxydiphenoyl-β-D-Glucose, (GHG) found predominantly in purple tea leaves, which shows potential in obesity management. Studies have indicated that these bioactive compounds play a significant role in reducing BMI and body weight among obese patients. This review focuses on how GHG impacts body weight and BMI in obese patients. A comprehensive literature review was conducted using Science Direct, Semantic Scholar, Wiley, PubMed, and Google Scholar databases up to 2024. The search employed both single keywords (e.g., 'purple tea', 'GHG', 'obesity') and multiple keyword combinations (e.g., 'purple tea and obesity', 'GHG and weight loss') related to purple tea, GHG, obesity, BMI, and clinical studies. The database search yielded 246 articles, with 173 articles retained after removing duplicates and studies published before 1999. This systematic approach aimed to gather comprehensive data on the phytochemistry, pharmacology, and potential therapeutic applications of purple tea. The investigation revealed that GHG operates through multiple mechanisms, such as inhibiting pancreatic lipase to reduce fat absorption, suppressing adipogenesis and lipogenesis, and preventing fatty tissue formation. Clinical investigations demonstrated significant reductions in BMI, waist circumference, and body weight among individuals consuming purple tea extracts with high GHG levels. Additional metabolic benefits include increased energy expenditure, improved insulin sensitivity, and enhanced glucose metabolism regulation. While more comprehensive research is needed to fully elucidate the optimal dosage and long-term effects, current evidence suggests that GHG from purple tea could be a valuable natural intervention in the multifaceted approach to obesity management.
... 13,14 Dietary interventions, increased physical activity, and behavior changes are necessary to promote weight loss even when medical interventions are planned. [15][16][17] Traditional dietary approaches include caloric restriction (CR), 17,18 with several meta-analyses reporting body weight and adipose tissue loss following various diets that depend on the intensity of the interventions, macronutrient compositions, and durations. [19][20][21][22][23][24] However, despite the beneficial effects of weight loss, poor compliance and adherence rates to dietary modulations, especially in the long term, remain problematic. ...
Article
The aim of the present study was to investigate the effects of long-term intermittent fasting (IF) on body composition and cardiometabolic health in adults with overweight and obesity. PubMed, Web of Science, and Scopus were searched from inception to March 2024 to identify original randomized trials that investigated the effects of IF versus either a control diet (CON) and/or continuous caloric restriction (CR). Participants were adults with overweight and obesity and intervention durations were ≥ 6 months. Overall, a total of 24 studies involving 2032 participants were included in the meta-analysis. Compared with CON, IF significantly reduced body weight [WMD: −2.84 kg], BMI [WMD: −1.41 kg.m2], fat mass [WMD: −3.06 kg], fat-free mass [WMD: −0.81 kg], waist circumference [WMD: −3.85 cm], visceral fat [SMD: −0.37], fasting glucose [WMD: −0.14 mmol/l], triglycerides [WMD: −0.12 mmol/l], and diastolic blood pressure [WMD: −2.24 mmHg]. Conversely, IF significantly increased high-density lipoproteins [WMD: 0.04 mmol/l] when compared with CON, but had no effects on insulin, hemoglobin A1c%, total cholesterol, low-density lipoprotein, or systolic blood pressure. Compared with CR, IF significantly reduced fat mass [WMD: −0.70 kg], body fat percentage [WMD: −0.59%], and DBP [WMD: −0.91 mmHg], and increased HDL [WMD: 0.03 mmol/l], with no other significant effects. Subgroup analyses showed that the mode of IF and intervention duration were the primary moderators of IF effects on the markers. In adults with overweight or obesity, IF and CR are comparably effective for reducing body weight and adiposity, as well as for improving cardiometabolic health markers.
... Intermittent fasting and continuous calorie restriction have been shown to produce similar weight loss outcomes. However, IF has demonstrated a superior ability to preserve lean body mass [56]. It is hypothesized that the effectiveness of IF in fat loss is attributed not only to calorie restriction, but also to the production of ketone bodies and enhanced lipid metabolism. ...
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There is a need to investigate the effect of lifestyle modifications on cardiometabolic health-related issues that occur during menopause. The aim of this study was to compare the effect of resistance and endurance circuit training program alone (exercise group, n = 34) with the effect of time-restricted eating (16:8) combined with a training program (combination group, n = 28) on cardiometabolic health in 62 menopausal women (aged 51.3 ± 4.69 years). Testing was conducted before and after a 12-week period and included an assessment of body composition, glycemic control, lipid panel, blood pressure, and anthropometric measurements. Decreases in body mass index and systolic blood pressure were significantly greater in the combination group than in the exercise group (F(1,60) = 4.482, p = 0.038, η² = 0.07; F(1,57) = 5.215, p = 0.026, η² = 0.08, respectively, indicating moderate effects). There were significant decreases in fat mass (p = 0.001, r = 0.654), glucose level (p = 0.017, r = 0.459), insulin level (p = 0.013, r = 0.467), homeostatic model assessment for insulin resistance (p = 0.009, r = 0.499), waist circumference (p = 0.002, r = 0.596), and waist-to-height ratio (p = 0.003, r = 0.588) (indicating moderate effect) in the combination group, while there were no significant changes in the exercise group. There were no changes in lipid panel indicators in either group. This is the first study to investigate the effect of time-restricted eating combined with exercise in menopausal women. The results of the study provide evidence that the combination of time-restricted eating and exercise leads to a greater body mass index reduction than exercise alone in menopausal women. Trial registration: ClinicalTrials.gov, NCT06138015 registered 18 November 2023—Retrospectively registered, https://clinicaltrials.gov/study/NCT06138015.
... 12 Despite its benefits, IF has some drawbacks, such as potential loss of lean body weight (BW) and a decline in physical function. 13 To counteract these, combining IF with exercise has shown to provide better results and a positive impact on physical function 14 Exercise methods for weight loss include high-intensity interval training (HIIT), 15 moderate-intensity continuous training (MICT), 16 and resistance and aerobic exercise (EX). 17 The combined effect of IF and exercise on weight loss is superior. ...
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Objective The purpose of this study is to utilize network meta‐analysis (NMA) to synthesize relevant randomized controlled trials (RCTs) and evaluate the most effective intermittent fasting (IF) combined with exercise interventions for weight loss. Methods This study searched five databases up until April 2024, obtaining RCTs that investigated the effects of intermittent fasting (IF) combined with exercise. The quality of the literature was assessed using the Cochrane tool, followed by a random‐effects statistical analysis of each intervention. Eventually, a NMA was conducted to compare the effectiveness of each intervention on weight loss, thereby determining their combined effectiveness on reducing weight. Results A total of nine trials, comparing 12 interventions involving 570 participants, were included. All interventions significantly reduced body weight (BW) and fat mass (FM) compared to the control (CON) group. In terms of BW reduction, the alternate‐day fasting + moderate‐intensity continuous training (ADF + MICT) intervention had the highest surface under the cumulative ranking curve average (SUCRA) score 88.1(MD: −4.44,95% CI −5.95, −2.92). Furthermore, for improving FM, the ADF + MICT intervention also had the highest SUCRA score 92.7(MD: −3.65,95% CI −5.05, −2.25), making it the optimal intervention for improving FM. Conclusion The NMA results indicate that all interventions are effective in reducing weight. Among them, ADF + MICT is the most effective strategy for reducing BW, and it is also the best approach for improving FM.
... Comparisons to other studies are limited due to a lack of similar study protocols; however, one study of a small group of women with overweight or obesity found intakes of vitamin E, calcium, iron, and zinc were significantly lower after a 23%-36% reduction in calorie intake over 16 wk on a prescribed diet [46], albeit nutrient adequacy was not assessed. The highest level of simulated caloric reduction in our analysis (50%) is in line with levels used in some studies to cause rapid weight loss for adults with morbid obesity [47][48][49][50][51]. Such a high level of caloric reduction (50%) is usually difficult to sustain [45] except with MBS. ...
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Background: Current guidelines for the treatment of obesity recommend dietary restriction to create a caloric deficit, and caloric reductions of 16% to 68% have been achieved in adults with overweight or obesity engaging in intentional weight loss programs. Objectives: This study models the impact of simulated caloric reduction on nutrient adequacy among U.S. adults !19 y with overweight or obesity using National Health and Nutrition Examination Survey data (2015-2018). Methods: Four levels of caloric reduction (20%, 30%, 40%, and 50%) were modeled by prorating daily calorie intake such that usual intakes of 14 nutrients were reduced proportional to caloric reduction. The percentages below the estimated average requirement (EAR) or above the adequate intake (AI) were estimated at each level of caloric reduction, with and without dietary supplement use. Differences across percentages of simulated caloric reductions were determined using nonoverlapping confidence intervals of the means (97.5 th percentile confidence intervals were used to approximate P < 0.05). Results: There were significant differences (P < 0.05) in percentages below the EAR (above the AI) between sequential levels of simulated caloric reduction for most of the nutrients analyzed (protein, vitamins A, B-6, folate, and C, calcium, iron, magnesium, potassium, and zinc). For example, after a simulated 30% caloric reduction, 25%-40% of the population had intakes below the EAR for protein, vitamin B-6, and zinc, and 75%-91% of the population had intakes below the EAR for vitamin A, calcium, and magnesium (vs. 4%-18% and 45%-56%, respectively, without caloric reduction). With the inclusion of dietary supplements, percentages below the EAR for all nutrients (except protein) were lower than those for food alone. Conclusions: Caloric reduction may exacerbate nutrient inadequacies among adults with overweight or obesity. Inclusion of nutrient-dense foods, fortified foods, specially formulated products, and/or dietary supplements should be considered for those on calorie-restricted diets for long-term weight loss.
... Many investigations have been carried out to assess the safety and tolerability of alternateday fasting regimens, showing promising clinical outcomes related to T2DM [104][105][106]. Research findings suggest that alternate-day fasting can serve as an alternative approach to continuous CR, with superior effects observed in the retention of lean mass [105,107]. The utilization of alternate-day fasting resulted in a significant decrease in total cholesterol and serum triglycerides [108]. ...
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Intermittent fasting has drawn significant interest in the clinical research community due to its potential to address metabolic complications such as obesity and type 2 diabetes mellitus. Various intermittent fasting regimens include alternate-day fasting (24 h of fasting followed by 24 h of eating), time-restricted fasting (fasting for 14 h and eating within a 10 h window), and the 5:2 diet (fasting for two days and eating normally for the other five days). Intermittent fasting is associated with a reduced risk of type 2 diabetes mellitus-related complications and can slow their progression. The increasing global prevalence of type 2 diabetes mellitus highlights the importance of early management. Since prediabetes is a precursor to type 2 diabetes mellitus, understanding its progression is essential. However, the long-term effects of intermittent fasting on prediabetes are not yet well understood. Therefore, this review aims to comprehensively compile existing knowledge on the therapeutic effects of intermittent fasting in managing type 2 diabetes mellitus and prediabetes.
... Caloric restriction Caloric restriction has been defined in various publications, with restrictions varying between 20% and 40% of ad libitum intake, [38][39][40] to 20% and 50% of needs, 41 to decreasing energy intake by 15% and 60% of baseline needs, 42 or to 10% and 25% of (usual) caloric intake. 43 Elsewhere, it has been defined as ''a state in which energy intake is sufficiently low to achieve or maintain a low-normal body weight status.'' ...
Article
Although fasting is increasingly applied for disease prevention and treatment, consensus on terminology is lacking. Using Delphi methodology, an international, multidisciplinary panel of researchers and clinicians standardized definitions of various fasting approaches in humans. Five online surveys and a live online conference were conducted with 38 experts, 25 of whom completed all 5 surveys. Consensus was achieved for the following terms: “fasting” (voluntary abstinence from some or all foods or foods and beverages), “modified fasting” (restriction of energy intake to max. 25% of energy needs), “fluid-only fasting,” “alternate-day fasting,” “short-term fasting” (lasting 2–3 days), “prolonged fasting” (≥4 consecutive days), and “religious fasting.” “Intermittent fasting” (repetitive fasting periods lasting ≤48 h), “time-restricted eating,” and “fasting-mimicking diet” were discussed most. This study provides expert recommendations on fasting terminology for future research and clinical applications, facilitating communication and cross-referencing in the field.
... Except one, 40 the studies included both male and female participants. Nine studies included patients with T2D, 25,36,37,41,[49][50][51][52]54 and five included participants with prediabetes. 35,36,[39][40][41] The IF intervention modes varied, with seven studies using TRE, 37-41,51,52 two studies using 5:2 fasting and feeding, 35,52 one study using 4:3 fasting and feeding, 26 one study using both TRE and ADF 35 (8) Were performed in non-T2D or prediabetes (24) Published more than once (3) Intervention duration less than 2 weeks (2) Studies eligible for the metaanalyses (n=14) ...
Article
Aim To perform a meta-analysis to investigate the effects of intermittent fasting (IF), as compared with either a control diet (CON) and/or calorie restriction (CR), on body composition and cardiometabolic health in individuals with prediabetes and type 2 diabetes (T2D). Methods PubMed, Web of Science, and Scopus were searched from their inception to March 2024 to identify original randomized trials with parallel or crossover designs that studied the effects of IF on body composition and cardiometabolic health. Weighted mean differences (WMDs) or standardized mean differences with 95% confidence intervals (CIs) were calculated using random-effects models. Results Overall, 14 studies involving 1101 adults with prediabetes or T2D were included in the meta-analysis. IF decreased body weight (WMD −4.56 kg [95% CI −6.23 to −2.83]; p = 0.001), body mass index (BMI; WMD −1.99 kg.m2 [95% CI −2.74 to −1.23]; p = 0.001), glycated haemoglobin (HbA1c; WMD −0.81% [95% CI −1.24 to −0.38]; p = 0.001), fasting glucose (WMD −0.36 mmol/L [95% CI −0.63 to −0.09]; p = 0.008), total cholesterol (WMD −0.31 mmol/L [95% CI −0.60 to −0.02]; p = 0.03) and triglycerides (WMD −0.14 mmol/L [95% CI −0.27 to −0.01]; p = 0.02), but did not significantly decrease fat mass, insulin, low-densitiy lipoprotein, high-density lipoprotein, or blood pressure as compared with CON. Furthermore, IF decreased body weight (WMD −1.14 kg [95% CI −1.69 to −0.60]; p = 0.001) and BMI (WMD −0.43 kg.m2 [95% CI −0.58 to −0.27]; p = 0.001), but did not significantly affect fat mass, lean body mass, visceral fat, insulin, HbA1c, lipid profiles or blood pressure. Conclusion Intermittent fasting is effective for weight loss and specific cardiometabolic health markers in individuals with prediabetes or T2D. Additionally, IF is associated with a reduction in body weight and BMI compared to CR, without effects on glycaemic markers, lipid profiles or blood pressure.
... Interestingly, accumulating data indicate that not only are fasting periods per se important for maintenance and improvement of metabolic health but also the timing of meals matters, favoring early intake of calories rather than late in the evening [82], although participants generally prefer to consume the meal at dinner time so they can engage in their habitual social eating patterns [4,[83][84][85][86][87]. Furthermore, ADF, compared with CR, could exhibit superior compliance with respect to CR [10,88], lacking the burden of persistent nutritional deprivation and other negative effects [5]. In dramatic contrast, other studies have reported that ADF could not be a possible dietary regimen because of extensive and constant hunger, as reported in different studies [89,90]. ...
Article
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Intermittent fasting (IF) has been indicated as a valuable alternative to the classical caloric restriction dietary regimen for lowering body weight and preventing obesity-related complications, such as metabolic syndrome and type II diabetes. However, is it effective? In this review article, we analyzed over 50 clinical studies in which IF, conducted by alternate day fasting (ADF) or time-restricted feeding (TRF), was compared with the caloric restriction approach. We evaluated the different roles of IF in treating and preventing human disorders such as metabolic syndrome, type II diabetes, and some types of cancer, as well as the usefulness of IF in reducing body weight and cardiovascular risk factors such as hypertension. Furthermore, we explored the cellular pathways targeted by IF to exert their beneficial effects by activating effector proteins that modulate cell functions and resistance to oxidative stress. In contrast, we investigated concerns regarding human health related to the adoption of IF dietary regimens, highlighting the profound debate surrounding weight loss regimens. We examined and compared several clinical trials to formulate an updated concept regarding IF and its therapeutic potential.
... Taken together, LEAP-2 inhibits the central function of ghrelin through crosstalk between the liver, stomach, and brain and acts to fine-tune the action of ghrelin in response to changing environmental conditions for regulation of food intake, energy partition, and homeostasis as well as the circadian rhythm. Time-restricted feeding (TRF) is a mode of intermittent fasting in which the daily eating window is restricted to 4-12 h [11]. Recent studies have indicated that TRF improves insulin sensitivity [12], 24 h glucose levels [6], glucose tolerance [13], lipid metabolism, the circadian clock [6,14], autophagy [6], and cardiac dysfunction [15], as well as metabolic dysfunction-associated steatotic liver disease (MASLD) [16]. ...
Article
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Liver-expressed antimicrobial peptide-2 (LEAP-2) has mutual antagonism with ghrelin, which evokes food intake under a freely fed state. Nevertheless, the impact of LEAP-2 on ghrelin under time-restricted feeding (TRF), which has benefits in the context of metabolic disease, is still unknown. This study aims to explore the impact of central administration of LEAP-2 on the ingestion behavior of rats, which was evaluated using their cumulative food intake in the TRF state. Before intracerebroventricular (ICV) administration of O-n-octanoylated ghrelin (0.1 nmol/rat), as a food-stimulatory model, the rats received various doses of LEAP-2 (0.3, 1, 3 nmol/rat, ICV). Cumulative food intake was recorded at 1, 2, 4, 8, 12, and 24 h after ICV injection under 12 h freely fed and TRF states in a light phase. In 12 h freely fed and TRF states, central administration of ghrelin alone induced feeding behavior. Pre-treatment with LEAP-2 (1 and 3 nmol/rat, ICV) suppressed ghrelin-induced food intake in a dose-dependent manner in a 12 h freely fed state instead of a TRF state, which may have disturbed the balance of ghrelin and LEAP-2. This study provides neuroendocrine-based evidence that may explain why TRF sometimes fails in fighting obesity/metabolic dysfunction-associated steatotic liver disease in clinics.
... Many investigations have been carried out to assess the safety and tolerability of alternate day fasting regimens, showing promising clinical outcomes related to T2DM [111][112][113]. Research findings suggest that alternate day fasting can serve as an alternative approach to continuous CR, with superior effects observed in the retention of lean mass [112,114]. The utilization of alternate-day fasting resulted in a significant decrease in total cholesterol and serum triglycerides [115]. ...
Preprint
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: Intermittent fasting has drawn significant interest in the clinical research community due to its potential to address metabolic complications such as obesity and type 2 diabetes mellitus. Various intermittent fasting regimens include alternate-day fasting (24 hours of fasting followed by 24 hours of eating), time-restricted fasting (fasting for 14 hours and eating within a 10-hour window), and the 5:2 diet (fasting for two days and eating normally for the other five days). Intermittent fasting is associated with a reduced risk of type 2 diabetes mellitus-related complications and can slow their progression. The increasing global prevalence of type 2 diabetes mellitus highlights the importance of early management. Since prediabetes is a precursor to type 2 diabetes mellitus, understanding its progression is essential. However, the long-term effects of intermittent fasting on prediabetes are not yet well understood. Therefore, this review aims to comprehensively compile existing knowledge on the therapeutic effects of intermittent fasting in managing type 2 diabetes mellitus and prediabetes.
... Intermittent fasting (IF) refers to a diet that alternates between fasting and free eating for a period of time to prevent and treat disease, such as obesity, type 2 diabetes mellitus and CVD, which includes time-restricted feeding (TRF, limiting eating to specific periods of time), 5∶2 diet (normal diet with 5 days and fasting diet with 2 days), and alternate-day fasting (ADF, eating normally one day and fasting lightly every other day) [9] . As a dietary pattern, IF is not a direct restriction of energy intake, but a fasting during a specific time and a free diet at other times, which is safer than the energy restriction [10] . ...
Article
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Circadian clock plays a vital role in the pathological progression of cardiovascular disease (CVD). Our previous studies showed that acrolein, an environmental pollutant, promoted atherosclerosis by reducing CLOCK/BMAL1 and disturbing circadian rhythm. Whereas, intermittent fasting (IF), a diet pattern, was able to ameliorate acrolein-induced atherosclerosis. In vivo, mice were fed acrolein 3 mg/kg/day via drinking water and IF for 18h (0:00-18:00). We observed that IF decreased acrolein-accelerated the formation of aortic lesion in ApoE -/- mice. Up-regulation of NF-κB, IL-1β and TNF-α levels were found in liver and heart tissue upon acrolein exposure, while was down-regulated by IF. Interestingly, IF treatment exhibited higher AMPK, p-AMPK and SIRT1and lower MAPK expression which was caused by acrolein. Besides, circadian genes Clock/ Bmal1 expression were suppressed and disturbed treated with acrolein, while were reversed by IF. Furthermore, consistent with that in vivo, short-term starvation as a fasting cell model in vitro could improve the disorders of CLOCK/BMAL1 and raised SIRT1 via regulating AMPK, as well as ROS-MAPK induced by acrolein. In conclusion, we demonstrated that IF repressed ROS-MAPK while activated AMPK to elevate the expression of circadian clock genes to ameliorate acrolein-induced atherogenesis, which shed a novel light to prevent cardiovascular diseases.
... 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). ...
Article
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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.
... kg, 95% CI = −0.40 to −0.02; p = 0.028) but no difference was observed in BMI reduction (SMD = 0.02 kg/m 2 , 95% CI = −0.16 to 0.20; p = 0.848) [39]. Another review suggested that IF and the calorie-restricted diet were equally effective in body weight loss (IF: 4-8% vs. calorie-restricted diet: 5-8%) and fat mass reduction (IF: 11-16% vs. calorie-restricted diet: 10-20%), but IF outperformed the calorie-restricted diet in lean mass retention [53]. Moreover, an earlier meta-analysis suggested that IF was comparable to the calorie-restricted diet (MD = −0.26 ...
Article
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The efficacy of intermittent fasting (IF), as an emerging weight management strategy, in improving cardiometabolic health has been evaluated in various populations, but that among Chinese individuals has not been systematically studied. A comprehensive search on multiple databases was performed to identify eligible randomized controlled trials (RCTs) up to October 2022. The primary outcome was post-intervention weight loss, and secondary outcomes included changes in cardiometabolic indicators. Effect estimates were meta-analyzed using a random-effects model. In total, nine RCTs with 899 Chinese participants were included. Time-restricted eating was the most adopted IF protocol in this study (six out of nine), followed by alternate-day fasting. The IF intervention significantly reduced body weight, body mass index, body fat mass, homeostatic model assessment of insulin resistance, low-density lipoprotein cholesterol, and triglycerides when compared with control groups. However, no statistically significant reductions in waist circumference, total cholesterol, high-density lipoprotein cholesterol, fasting glucose, systolic blood pressure, and diastolic blood pressure were found. To sum up, IF can be a weight management strategy and may improve the cardiometabolic health of Chinese adults, but more long-term trials using different IF strategies are required to generate robust evidence of its efficacy.
... Интервальное голодание вызывает потерю веса на 3-8 % в течение периода от 3 до 24 недель, что на фоне большинства диет для похудения является значимым результатом (Johnstone, 2015). В дополнение к меньшей потере мышечной массы, чем стандартное ограничение калорий, оно способствует увеличению скорости метаболизма на 3,6-14 % (Varady, 2011;Johnstone, 2015). Другие преимущества: интервальное голодание может снизить маркеры воспаления, уровень холестерина, триглицеридов в крови и уровень сахара в крови (Varady, 2009). ...
... In addition, the calorie restriction diet (CRD) entails a sustained reduction in daily caloric intake of roughly 25-30% from the average calorie intake (22). The CRD is effective in terms of weight loss and disease risk (23). The most immediate and noticeable effect of a calorie-restricted diet is often weight loss. ...
Article
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Introduction Dietary habits in Saudi Arabia have been shifting toward the Western diet, which is high in fat, salt, and sugar, leading to a high obesity rate. Different dietary strategies such as the Ketogenic Diet (KD), Intermittent Fasting (IF), Gluten Free Diet (GFD), and Calorie Restriction Diet (CRD) have shown an influential role in weight loss. This study aimed to compare trending diets and correlate different types of diet with obesity and lifestyle among adults in Saudi Arabia. Methods A cross-sectional study was performed on Saudis and non-Saudis over 18 years old. We used convenience sampling, an online questionnaire distributed via social media channels, including WhatsApp, LinkedIn, and Twitter. SPSS 28 software was applied for data analysis. The chi-square test was used to determine associations between different variables. Statistical significance was considered at a value of p less than 0.05. Results Most participants were females residing in the Eastern and Central regions of Saudi Arabia. Although most do not follow any dietary plan, they exhibited acceptable exercise and lifestyle. The minority of the study population followed different types of diet plans, such as KD, IF, and GFD. The purpose of most of the participants who have used these strategies was for weight loss but failed to sustain the dietary plan for more than 1 month. Conclusion Obesity remains a challenging issue in Saudi Arabia. Adherence to dietary regimes could help in controlling obesity. Increasing the awareness of the benefits of each dietary plan for health, choosing the appropriate one, and sustaining a balanced nutrition pattern.
... Nevertheless, loss of lean mass is not preferable during weight loss, and physical activity should be considered as a co-intervention to maintain lean mass during weight loss with SAAR. It is important to note that we were unable to differentiate between fat free mass compartments (including total body water), and that the predicted loss of fat free mass in the SAAR group is comparable to other interventions with calorie restriction [71]. ...
Article
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Background Dietary sulfur amino acid restriction (SAAR) improves metabolic health in animals. 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 humans with overweight or obesity. Methods N = 59 participants with overweight or obesity (73% women) were randomized stratified by sex to an 8-week plant-based dietary intervention low (~ 2 g/day, SAAR) or high (~ 5.6 g/day, control group) in sulfur amino acids. The diets were provided in full to the participants, and both investigators and participants were blinded to the intervention. Outcome analyses were performed using linear mixed model regression adjusted for baseline values of the outcome and sex. Results SAAR led to a ~ 20% greater weight loss compared to controls (β 95% CI − 1.14 (− 2.04, − 0.25) kg, p = 0.013). 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 processes related to structural components were downregulated. Conclusion Our study shows that SAAR leads to greater weight loss, decreased leptin and increased ketone bodies compared to controls. Further research on SAAR is needed to investigate the therapeutic potential for metabolic conditions in humans. Trial registration: ClinicalTrials.gov identifier: NCT04701346, registered Jan 8th 2021, https://www.clinicaltrials.gov/study/NCT04701346
... Caloric restriction Caloric restriction has been defined in various publications, with restrictions varying between 20% and 40% of ad libitum intake, [38][39][40] to 20% and 50% of needs, 41 to decreasing energy intake by 15% and 60% of baseline needs, 42 or to 10% and 25% of (usual) caloric intake. 43 Elsewhere, it has been defined as ''a state in which energy intake is sufficiently low to achieve or maintain a low-normal body weight status.'' ...
... 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. ...
Article
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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. ...
Article
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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). ...
Article
Full-text available
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. ...
Preprint
Full-text available
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 . ...
Article
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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.
Conference Paper
The global obesity epidemic is a significant challenge to public health, necessitating innovative and personalized solutions. This paper presents Pondera, an innovative mobile app revolutionizing weight management by integrating Artificial Intelligence (AI) and multidimensional goal fulfilment analytics. Pondera distinguishes itself by supplying a tailored approach to weight loss, combining individual user data, including dietary preferences, fitness levels, and specific weight loss objectives, with advanced AI algorithms to generate personalized weight loss plans. Future development directions include refining AI algorithms, enhancing user experience, and validating effectiveness through comprehensive studies, ensuring Pondera becomes a pivotal tool in achieving sustainable weight loss and health improvement.
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Background Intermittent fasting (IF) holds promise for enhancing metabolic health. However, the optimum IF forms and their superiority over continuous energy restriction (CER) remain unclear due to disconnected findings. Methods We systematically searched PubMed, Embase, and the Cochrane databases for meta-analyses of randomized controlled trials (RCTs) investigating the association between IF and metabolic health outcomes. Subsequently, we performed an umbrella review and network meta-analysis (NMA) to evaluate the efficacy of different forms of IF (time-restricted eating (TRE), alternate-day fasting (ADF), and 5:2 diet (regular eating for 5 days and energy restriction for 2 days per week)) compared to CER and usual diets on metabolic health outcomes. To assess the certainty of both direct and indirect estimates, we employed the Confidence in Network Meta-Analysis (CINeMA) approach. Additionally, we calculated the surface under the cumulative ranking curve (SUCRA) for each dietary strategy to determine their ranking in terms of metabolic health benefits. Results Ten of the best and non-redundant meta-analysis studies, involving 153 original studies and 9846 participants, were included. When considering direct evidence only, all IF forms significantly reduced body weight compared to usual diets. In NMA incorporating indirect evidence, all IF regimens also significantly reduced body weight compared to usual diets. In the SUCRA of NMA, IF ranked higher than usual diets or CER in 85.4% and 56.1% of the outcomes, respectively. ADF had the highest overall ranking for improving metabolic health (ranked first: 64.3%, ranked second: 14.3%). Conclusions Overall, all IF forms demonstrate potentials to improve metabolic health, with ADF appearing to produce better outcomes across investigated outcomes. Further high-quality trials are warranted to confirm the (relative) efficacy of IF on metabolic health. Trial registration PROSPERO (record no: CRD42022302690).
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Intermittent fasting (IF) has been indicated as a valuable alternative to the classical caloric restriction dietary regimen for lowering body weight and preventing obesity-related complications such as metabolic syndrome and type II diabetes. However, is it effective? In this review article, we analyzed over 50 clinical studies in which IF, conducted by alternate day fasting (ADF) or time-restricted feeding (TRF), was compared with the caloric restriction approach. We evaluated the different roles of IF in treating and preventing human disorders such as metabolic syndrome, type II diabetes, and some types of cancer, as well as the usefulness of IF in reducing body weight and cardiovascular risk factors such as hypertension. Furthermore, we explored the cellular pathway targeted by IF to exert their beneficial effects by activating effector proteins that modulate cell functions and resistance to oxidative stress. In contrast, we investigated the concerns for human health related to the adoption of IF dietary regimen, highlighting the profound debate on weight loss regimens. We have examined and compared several clinical trials to formulate an updated conception regarding IF and its therapeutic potential.
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Fasting diets (FDs) have drawn great attention concerning their contribution to health and disease over the last decade. Despite considerable interest in FDs, the effect of fasting diets on eating behaviors, sleep, and mood-essential components of diet satisfaction and mental health- has not been addressed comprehensively. Understanding the critical role that fasting plays in these elements will open up potential treatment avenues that have not yet been explored. The aim of the present paper was to conduct a comprehensive critical review exploring the effects of fasting on eating behaviors, sleep, and mood. There is currently a lack of clarity regarding which fasting option yields the most advantageous effects, and there is also a scarcity of consistent trials that assess the effects of FDs in a comparable manner. Similarly, the effects and/or treatment options for utilizing FDs to modify eating and sleep behaviors and enhance mood are still poorly understood. Further researches aiming at understanding the impacts of various fasting regimes, providing new insights into the gut-brain axis and offering new treatment avenues for those with resistant anxiety and depression, are warranted. Alteration of eating behaviors can have lasting effects on various physiological parameters. The use of fasting cures can underpin ancient knowledge with scientific evidence to form a new approach to the prevention and treatment of problems associated with co-morbidities or challenges pertaining to eating behaviors. Therefore, a thorough examination of the various fasting regimens and how they impact disease patterns is also warranted.
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Fasting has gained significant attention in recent years for its potential health benefits in various body systems. This review aims to comprehensively examine the effects of fasting on human health, specifically focusing on its impact on different body's physiological systems. The cardiovascular system plays a vital role in maintaining overall health, and fasting has shown promising effects in improving cardiovascular health markers such as blood pressure, cholesterol levels, and triglyceride levels. Additionally, fasting has been suggested to enhance insulin sensitivity, promote weight loss, and improve metabolic health, thus offering potential benefits to individuals with diabetes and metabolic disorders. Furthermore, fasting can boost immune function, reduce inflammation, enhance autophagy, and support the body's defense against infections, cancer, and autoimmune diseases. Fasting has also demonstrated a positive effect on the brain and nervous system. It has been associated with neuroprotective properties, improving cognitive function, and reducing the risk of neurodegenerative diseases, besides the ability of increasing the lifespan. Hence, understanding the potential advantages of fasting can provide valuable insights for individuals and healthcare professionals alike in promoting health and wellbeing. The data presented here may have significant implications for the development of therapeutic approaches and interventions using fasting as a potential preventive and therapeutic strategy.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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).
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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.
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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.
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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.
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Conflicting recommendations are prevalent regarding the appropriateness of red meat versus white meat consumption for individuals aiming to reduce body weight and cardiovascular disease risk. We examined changes in body weight and lipid profiles in a 12-wk, randomized, controlled trial, in which overweight women followed a hypocaloric diet with lean beef or chicken as the primary protein source, while participating in a fitness walking program. Sedentary non-smoking females (n = 61), age 43.4 +/- 7.8 years, with body mass indexes of 32.1 +/- 3.4 kg/m(2) (means +/- standard deviation), followed calculated-deficit diets (-500 kcal daily) and were randomly assigned to the beef-consumption or chicken-consumption dietary group, while following a fitness walking program. Body weight, body composition (by hydrodensitometry), and blood lipid profiles were measured at baseline and 12 wk. Weight loss was significant within (P < 0.05) but similar between (P > 0.05) the beef-consumption (5.6 +/- 0.6 kg, mean +/- standard error) and the chicken-consumption (6.0 +/- 0.5 kg) groups. Both groups showed significant reductions in body fat percentage (P < 0.05) and total (P < 0.05) and low-density lipoprotein (P < 0.05) cholesterol, with no significant differences between groups. High-density lipoprotein cholesterol did not change significantly in either group. These findings demonstrated that weight loss and improved lipid profile can be accomplished through diet and exercise, whether the dietary protein source is lean beef or chicken.
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Increased body weight is a strong risk factor for hypertension. A meta-analysis of randomized controlled trials was performed to estimate the effect of weight reduction on blood pressure overall and in population subgroups. Twenty-five randomized, controlled trials (comprising 34 strata) published between 1966 and 2002 with a total of 4874 participants were included. A random-effects model was used to account for heterogeneity among trials. A net weight reduction of -5.1 kg (95% confidence interval [CI], -6.03 to -4.25) by means of energy restriction, increased physical activity, or both reduced systolic blood pressure by -4.44 mm Hg (95% CI, -5.93 to -2.95) and diastolic blood pressure by -3.57 mm Hg (95% CI, -4.88 to -2.25). Blood pressure reductions were -1.05 mm Hg (95% CI, -1.43 to -0.66) systolic and -0.92 mm Hg (95% CI, -1.28 to -0.55) diastolic when expressed per kilogram of weight loss. As expected, significantly larger blood pressure reductions were observed in populations with an average weight loss >5 kg than in populations with less weight loss, both for systolic (-6.63 mm Hg [95% CI, -8.43 to -4.82] vs -2.70 mm Hg [95% CI, -4.59 to -0.81]) and diastolic (-5.12 mm Hg [95% CI, -6.48 to -3.75] vs -2.01 mm Hg [95% CI, -3.47 to -0.54]) blood pressure. The effect on diastolic blood pressure was significantly larger in populations taking antihypertensive drugs than in untreated populations (-5.31 mm Hg [95% CI, -6.64 to -3.99] vs -2.91 mm Hg [95% CI, -3.66 to -2.16]). This meta-analysis clearly shows that weight loss is important for the prevention and treatment of hypertension.
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The purpose of this study was to determine whether improvements in insulin sensitivity with weight loss are mediated by changes in inflammation in obese, postmenopausal women. We studied 58 sedentary, overweight, and obese (BMI 33 +/- 1 kg/m(2), means +/- SEM) postmenopausal (58 +/- 1 year) women at baseline and 37 women who completed 6 months of weight loss induced by diet and exercise. The women underwent 3-h hyperinsulinemic-euglycemic clamps (40 mU x m(-2) x min(-1)) to determine glucose utilization (M). Insulin sensitivity was determined as M/I, the amount of glucose metabolized per unit of plasma insulin (I). Visceral adipose tissue (VAT) and plasma concentrations of C-reactive protein (CRP), cytokines interleukin (IL)-6, and tumor necrosis factor (TNF)-alpha, as well as their soluble receptors, were measured. At baseline, CRP concentration was a predictor of both glucose utilization and insulin sensitivity, independent of adiposity, race, and aerobic fitness (M: partial r = -0.30, P = 0.03, and M/I: partial r = -0.32, P = 0.02). Weight loss resulted in significant reductions in body weight, fat mass, VAT, and fasting glucose and insulin levels (P < 0.05). Both glucose utilization and insulin sensitivity increased by 16% (P < 0.05). CRP, IL-6, and soluble TNF receptor (sTNFR)-1 concentrations decreased (P < 0.05), but concentrations of TNF-alpha, sTNFR-2, and soluble IL-6 receptor (IL-6sR) did not change. In stepwise regression models to predict changes in glucose homeostasis, changes in VAT and sTNF-R1 independently predicted changes in glucose utilization (r = -0.49 and cumulative r = -0.64, P < 0.01), while changes in VAT and IL-6 were both independent predictors of changes in insulin sensitivity (r = -0.57 and cumulative r = -0.68, P < 0.01). Improvements in glucose metabolism with weight loss programs are independently associated with decreases in cytokine concentrations, suggesting that a reduction in inflammation is a potential mechanism that mediates improvements in insulin sensitivity.
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A comprehensive program of lifestyle modification induces loss of approximately 10% of initial weight in 16 to 26 weeks, as revealed by a review of recent randomized controlled trials, including the Diabetes Prevention Program. Long-term weight control is facilitated by continued patient-therapist contact, whether provided in person or by telephone, mail, or e-mail. High levels of physical activity and the consumption of low-calorie, portion-controlled meals, including liquid meal replacements, can also help maintain weight loss. Additional studies are needed of the effects of macronutrient content (e.g., low-fat vs. low-carbohydrate diets) on long-term changes in weight and health. Research also is needed on effective methods of providing comprehensive weight loss control to the millions of Americans who need it.