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Effectiveness of an intermittent fasting diet versus regular diet on fat loss in overweight and obese middle-aged and elderly people without metabolic disease: a systematic review and meta-analysis of randomized controlled trials.
Yao, K, Su, H, Cui, K, Gao, Y, Xu, D, Wang, Q, Ha, Z, Zhang, T, Chen, S, Liu, T
The journal of nutrition, health & aging. 2024;(3):100165
Abstract
OBJECTIVE As the number of adults aged over 40 with obesity increases dramatically, intermittent fasting interventions (IF) may help them to lose fat and weight. This systematic review investigated the most recent research on the effects of intermittent fasting and a regular diet on body composition and lipids in adults aged over 40 with obesity without the metabolic disease. DATA SOURCES Randomized controlled trials (RCTs) on IF on adults aged over 40 with obesity were retrieved from PubMed, Web of Science, EBSCO, China Knowledge Network (CNKI), VIP database, Wanfang database with the experimental group using IF and the control group using a regular diet. Revman was used for meta-analysis. Effect sizes are expressed as weighted mean differences (WMD) and 95% confidence intervals (CI). STUDY SELECTION A total of 9 articles of randomised controlled trials that met the requirements were screened for inclusion. Studies typically lasted 2-6 weeks. The experimental population was aged 42-66 years, with a BMI range of 25.7-35 kg/m2. SYNTHESIS A total of 9 RCTs were included. meta-analysis showed that body weight (MD: -2.05 kg; 95% CI (-3.84, -0.27); p = 0.02), BMI (MD: -0.73 kg/m2; 95% CI (-1.05, -0.41); p < 0.001), fat mass (MD: -2.14 kg; 95% CI (-3.81, 0.47); p = 0.01), and TG (MD = -0.32 mmol/L, 95% CI (-0.50, -0.15, p < 0.001) were significantly lower in the experimental group than in the control group. No significant reduction in lean body mass (MD: -0.31 kg; 95% CI (-0.96, 0.34); p = 0.35). CONCLUSION IF had a reduction in body weight, BMI, fat mass, and TG in adults aged over 40 with obesity without metabolic disease compared to RD, and IF did not cause a significant decrease in lean body mass, which suggests healthy and effective fat loss. However, more long-term and high-quality trials are needed to reach definitive conclusions.
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Comparative efficacy of energy-restricted dietary interventions in overweight and obese populations: A systematic review and network meta-analysis.
Zhao, J, Duan, X, Zhang, L, Zhao, X, Yang, J, Sun, N, Zhao, W
Nursing & health sciences. 2024;(1):e13083
Abstract
This meta-analysis compared the effectiveness of different energy-restricted diets on body composition, glucose metabolism, and lipid metabolism in overweight and obese populations. Five databases were searched to identify relevant studies in English from inception until July 20, 2023, for randomized controlled trials of at least 2 weeks duration assessing the effects of continuous energy-restricted diets compared with any intermittent energy-restricted diet in obesity adults. The risk of bias was assessed using the Cochrane Risk of Bias Tool version 2.0, while the Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) system was used to assess the certainty of the evidence. A non-informative prior distribution Bayesian network meta-analysis was conducted. Thirty-eight studies (3039 participants) assessing four energy-restricted diets were included. Three RCTs were at high risk of bias with a very low to moderate certainty of evidence. Combined with pairwise comparisons and surface under the cumulative ranking curve, alternate-day fasting may be the best energy restriction regimen with the potential to have the most beneficial effects on various aspects of the obesity population. More rigorously designed and long-term follow-up studies are warranted.
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Combined versus independent effects of exercise training and intermittent fasting on body composition and cardiometabolic health in adults: a systematic review and meta-analysis.
Khalafi, M, Symonds, ME, Maleki, AH, Sakhaei, MH, Ehsanifar, M, Rosenkranz, SK
Nutrition journal. 2024;(1):7
Abstract
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.
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Network meta-analysis of three different forms of intermittent energy restrictions for overweight or obese adults.
Ma, Y, Sun, L, Mu, Z
International journal of obesity (2005). 2024;(1):55-64
Abstract
This network meta-analysis aimed to compare the efficacy of three forms of intermittent energy restriction (IER), including alternate-day fasting (ADF), the 5:2 diet, and time-restricted feeding (TRF), in overweight or obese adults. A literature search was conducted in PubMed, Embase, Cochrane Library, and China National Knowledge Infrastructure (CNKI) to find relevant randomized controlled trials (RCTs) until August 10, 2022. The modified Cochrane risk of bias assessment tool was applied to assess the methodological quality of eligible studies. Random network meta-analysis was conducted using STATA 14.0. Sixteen RCTs were included, with 1228 patients. Overall, the methodological quality ranged from low to moderate. ADF was superior to CER and 5:2 diet in reducing waist circumference, whereas 5:2 diet was superior to CER in reducing BMI. Regarding fat mass and drop-out, all forms of IER were comparable. Sensitivity analyses indicated that the type of individuals had no influence on the pooled results; nevertheless, ADF significantly reduced weight compared to CER and achieved significant waist circumference reduction compared to CER, 5:2 diet, and TRF. ADF may be preferentially prescribed for overweight or obese adults. More large-scale and high-quality studies are required, however, to investigate the effect of TRF on overweight and obesity.
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Effects of Intermittent Energy Restriction Compared with Those of Continuous Energy Restriction on Body Composition and Cardiometabolic Risk Markers - A Systematic Review and Meta-Analysis of Randomized Controlled Trials in Adults.
Schroor, MM, Joris, PJ, Plat, J, Mensink, RP
Advances in nutrition (Bethesda, Md.). 2024;15(1):100130
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Intermittent energy restriction (IER) diets, such as the 5:2 diet, time-restricted eating (TRE), and alternate-day fasting (ADF), are gaining popularity. According to previous research, IER protocols effectively manage obesity and may have many other health benefits, including improving metabolic health. This systematic review and meta-analysis of twenty-eight parallel-design randomised controlled trials looked at the benefits of IER protocols, such as ADF, TRE, and the 5:2 diet, and the effects of continuous energy restriction (CER) on anthropometric and cardiometabolic outcomes. The results of this systematic review and meta-analysis showed that both the IER and CER are equally beneficial. However, IER protocols showed greater but clinically insignificant improvements in fat-free mass and waist circumference in healthy adults. IER and CER protocols were not different in improving the lipid profile, glucose and insulin levels and blood pressure. Different IER diets showed different positive effects on metabolic parameters. Future robust studies are required to assess the effects of these energy-restriction diets on metabolic and anthropometric parameters because of the high variability in the included studies. However, healthcare professionals can use the results of this review to understand the potential clinical utility of various energy-restriction diets.
Abstract
The interest in intermittent energy restriction (IER) diets as a weight-loss approach is increasing. Different IER protocols exist, including time-restricted eating (TRE), alternate-day fasting (ADF), and the 5:2 diet. This meta-analysis compared the effects of these IER diets with continuous energy restriction (CER) on anthropometrics and cardiometabolic risk markers in healthy adults. Twenty-eight trials were identified that studied TRE (k = 7), ADF (k = 10), or the 5:2 diet (k = 11) for 2-52 wk. Energy intakes between intervention groups within a study were comparable (17 trials), lower in IER (5 trials), or not reported (6 trials). Weighted mean differences (WMDs) were calculated using fixed- or random-effects models. Changes in body weight [WMD: -0.42 kg; 95% confidence interval (CI): -0.96 to 0.13; P = 0.132] and fat mass (FM) (WMD: -0.31 kg; 95% CI: -0.98 to 0.36; P = 0.362) were comparable when results of the 3 IER diets were combined and compared with those of CER. All IER diets combined reduced fat-free mass (WMD: -0.20 kg; 95% CI: -0.39 to -0.01; P = 0.044) and waist circumference (WMD: -0.91 cm; 95% CI: -1.76 to -0.06; P = 0.036) more than CER. Effects on body mass index [BMI (kg/m2)], glucose, insulin, homeostatic model assessment for insulin resistance (HOMA-IR), serum lipid and lipoprotein concentrations, and blood pressure did not differ. Further, TRE reduced body weight, FM, and fat-free mass more than CER, whereas ADF improved HOMA-IR more. BMI was reduced less in the 5:2 diet compared with CER. In conclusion, the 3 IER diets combined did not lead to superior improvements in anthropometrics and cardiometabolic risk markers compared with CER diets. Slightly greater reductions were, however, observed in fat-free mass and waist circumference. To what extent differences in energy intakes between groups within studies may have influenced these outcomes should be addressed in future studies.
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Effects of intermittent fasting regimens on glycemic, hepatic, anthropometric, and clinical markers in patients with non-alcoholic fatty liver disease: Systematic review and meta-analysis of randomized controlled trials.
Saleh, SAK, Santos, HO, Găman, MA, Cerqueira, HS, Zaher, EA, Alromaih, WR, Arafat, NS, Adi, AR, Adly, HM, Alyoubi, R, et al
Clinical nutrition ESPEN. 2024;:70-80
Abstract
OBJECTIVES Intermittent fasting (IF) regimens have been hypothesized to influence several markers of cardiometabolic and liver function. The objective of our meta-analysis was to investigate the impact of IF regimens on cardiometabolic and liver markers in subjects diagnosed with non-alcoholic fatty liver disease (NAFLD). METHODS We searched several online databases (PubMed/Medline, Web of Science, Scopus and Embase) in order to identify suitable publications for inclusion in the meta-analysis. Results were expressed as weighted mean differences (WMD). RESULTS From 12343 articles identified in different databases, a total of 7 RCT arms were entered into the quantitative synthesis. The manuscripts were published between 2019 and 2023. IF regimens (the 5:2 diet, 16/8 time-restricting feeding, and alternate day fasting) varied from 2 months to 3 months. IF regimens reduced steatosis scores (WMD: -33.22 CAP dB/m, 95 % CI: -50.72 to -15.72), anthropometric characteristics of obesity (WMD: -0.77 kg/m2, 95 % CI: -1.38 to -0.17 for body mass index; WMD: -3.16 kg, 95 % CI: -4.71 to -1.61 for body weight; WMD: -1.90 kg, 95 % CI: -3.51 to -0.29 for waist circumference), as well as ALT (WMD: -9.10 U/L, 95 % CI: -12.45 to -5.75), triglyceride (WMD: -20.83 mg/dl, 95 % CI: -39.01 to -2.66), total cholesterol (WMD: -7.80 mg/dl, 95 % CI: -15.18), HbA1c (WMD: -0.14 %, 95 % CI: -0.20 to -0.08) and HOMA-IR (WMD: -1.21, 95 % CI: -2.08 to -0.34) levels versus controls. Nevertheless, no between-group differences were detected for other biomarkers, e.g., fasting blood glucose, insulin, AST, HDL-C or LDL-C values, and fibrosis scores. CONCLUSION IF regimens can improve some markers of cardiometabolic and liver function in patients with NAFLD. However, the available evidence to support the benefits of IF regimens is limited and derived from a small number of studies, thus further research is needed to clarify the impact of IF on the cardiometabolic health of NAFLD patients.
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Intermittent fasting regimens for metabolic dysfunction-associated steatotic liver disease: a systematic review and network meta-analysis of randomized controlled trials.
Abuelazm, MT, Mohamed, I, Naeem, A, Khlidj, Y, Tanashat, M, Katamesh, BE, Abusuilik, H, Altobaishat, O, Abdelnabi, M, Abdelazeem, B
European journal of gastroenterology & hepatology. 2024;(4):371-381
Abstract
Metabolic dysfunction-associated steatotic liver disease (MASLD) is a prevalent metabolic disorder characterized by excessive hepatic fat accumulation. Intermittent fasting (IF) has emerged as a potential therapeutic strategy with the ability to induce weight loss, improve insulin sensitivity and reduce hepatic steatosis. We aim to compare the efficacy of different IF regimens for MASLD management. A systematic review and network meta-analysis of randomized controlled trials investigating different IF regimens for MASLD. PubMed , EMBASE , WOS , SCOPUS and Cochrane Central Register of Controlled Trials were searched until 10 April 2023. Analysis was performed using R software with the meta and netmeta packages. Mean difference (MD) was used to pool continuous outcomes with 95% confidence intervals (CIs). Our meta-analysis was registered in PROSPERO (CRD42023418467). Our meta-analysis included eight randomized controlled trials with a total of 635 participants. The 5 : 2 diet significantly improved liver stiffness (MD, -0.32; 95% CI, -0.55 to -0.09; P < 0.01). Time-restricted feeding significantly improved liver steatosis (controlled attenuation parameter score) (MD, -39.83; 95% CI, -64.78 to -14.87; P < 0.01). No significant changes were observed in asparate aminotransferase, gamma-glutamyl transpeptidase, low-density lipoproteins cholesterol, total cholesterol, triglyceride levels, basal metabolic index, blood pressure, Homeostatic Model Assessment of Insulin Resistance, fasting blood sugar, lean body mass or waist circumference across all IF regimens. However, alternate-day fasting showed positive results in anthropometric measures, including significant improvements in lean body mass, waist circumference, fat mass and weight reduction ( P < 0.05). IF regimens showed various positive effects on clinical outcomes in MASLD patients; however, these effects were not consistent. Therefore, a patient-tailored IF regimen should be considered.
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Circadian alignment of food intake and glycaemic control by time-restricted eating: A systematic review and meta-analysis.
Rovira-Llopis, S, Luna-Marco, C, Perea-Galera, L, Bañuls, C, Morillas, C, Victor, VM
Reviews in endocrine & metabolic disorders. 2024;(2):325-337
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Daily rhythms of metabolic function are supported by molecular circadian clock systems that are strongly regulated by feeding and fasting. Intermittent fasting diets have been associated with weight loss and improved metabolism. However, the effects of time-restricted eating (TRE) on glycemic parameters are still under debate. In this review, we aim to systematically analyze the effects of TRE on glycemic parameters. We searched on PubMed, EMBASE, and the Cochrane Library for controlled studies in which subjects followed TRE for at least 4 weeks. 20 studies were included in the qualitative systematic review, and 18 studies (n = 1169 subjects) were included in the meta-analysis. Overall, TRE had no significant effect on fasting glucose (Hedges's g = -0.08; 95% CI:-0.31,0.16; p = 0.52), but it did reduce HbA1c levels (Hedges's g = -0.27; 95% CI: -0.47, -0.06; p = 0.01). TRE significantly reduced fasting insulin (Hedges's g = -0.40; 95% CI: -0.73,-0.08; p = 0.01) and showed a tendency to decrease HOMA-IR (Hedges's g = -0.32; 95% CI:-0.66,0.02; p = 0.06). Interestingly, a cumulative analysis showed that the beneficial effects of TRE regarding glucose levels were less apparent as studies with later TRE windows (lTRE) were being included. Indeed, a subgroup analysis of the early TRE (eTRE) studies revealed that fasting glucose was significantly reduced by eTRE (Hedges's g = -0.38; 95% CI:-0.62, -0.14; p < 0.01). Our meta-analysis suggests that TRE can reduce HbA1c and insulin levels, and that timing of food intake is a crucial factor in the metabolic benefit of TRE, as only eTRE is capable of reducing fasting glucose levels in subjects with overweight or obesity.PROSPERO registration number CRD42023405946.
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Intermittent fasting improves hepatic end points in nonalcoholic fatty liver disease: A systematic review and meta-analysis.
Lange, M, Nadkarni, D, Martin, L, Newberry, C, Kumar, S, Kushner, T
Hepatology communications. 2023;(8)
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Abstract
BACKGROUND AND AIMS Despite NAFLD being the most prevalent liver disease globally, currently there are no FDA-approved treatments, and weight loss through caloric restriction and enhanced physical activity is the recommended treatment strategy. Intermittent fasting (IF) has been proposed as an alternative strategy with additional cardiometabolic benefits. In this systematic review and meta-analysis, we evaluated the anthropometric, biochemical, and hepatic impacts of IF in patients with NAFLD. METHODS MEDLINE, EMBASE, Cochrane Central, and conference abstracts were searched for IF interventions in adults with NAFLD until April 2, 2023. Meta-analysis with a random effects model was used to compare pre-intervention and post-intervention changes in anthropometric, biochemical, and hepatic end points in the IF intervention group with the control group. Publication bias was assessed using Egger's test. RESULTS Fourteen studies were included in the systematic review and ten in the meta-analysis (n = 840 participants, 44.64% male). Studies varied in modalities for NAFLD diagnosis, duration of IF (4-52 weeks), and type of IF (5:2 diet, modern alternate-day fasting, time-restricted eating, or religious fasting). Body weight, body mass index, and waist to hip ratio all significantly improved following fasting intervention (p< 0.05). Adults with NAFLD showed an improvement in serum alanine transaminase, aspartate aminotransferase, hepatic steatosis (controlled attenuation parameter measured by vibration-controlled transient elastography), and hepatic stiffness (measured by vibration-controlled transient elastography) after fasting intervention (p < 0.05). CONCLUSIONS There is limited, but moderate- to high-quality evidence to suggest that IF can improve hepatic end points and promote weight loss in adults with NAFLD. Larger randomized controlled studies with extended duration are needed to further validate our findings.
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Does intermittent fasting impact mental disorders? A systematic review with meta-analysis.
Fernández-Rodríguez, R, Martínez-Vizcaíno, V, Mesas, AE, Notario-Pacheco, B, Medrano, M, Heilbronn, LK
Critical reviews in food science and nutrition. 2023;(32):11169-11184
Abstract
Accumulating evidence supports the benefits of intermittent fasting (IF) as a dietary strategy for cardiometabolic health and weight control. However, little is known about the potential implications of IF on mental disorders. The aim of this review was to synthesize evidence regarding the effects of IF on mental disorders (depression, anxiety, and mood state) in the general population. We conducted a systematic search in five databases from inception to January 2022. Randomized and nonrandomized clinical trials (RCTs/nonRCTs) were included. A random effects method was used to pool standardized mean differences (SMDs) and 95% CIs. A total of 14 studies involving 562 individuals were included, of which 8 were RCTs and 6 were nonRCTs. IF showed a moderate and positive effect on depression scores when compared to control groups (SMD: 0.41; 95%CI: 0.05 to 0.76; I2=45%; n = 4). Conversely, within-group analyses did not show any significant effect of IF on anxiety (SMD: 0.10; 95%CI: -0.09 to 0.30; I2=0%; n = 5) or mood state (SMD: 0.14; 95%CI: -0.09 to 0.37; I2=59%; n = 7). IF modalities did not negatively impact mental disorders in the general population. In fact, IF showed a positive influence on diminishing depression scores, and did not modify anxiety or mood.