1.
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
-
-
-
Free full text
Plain language summary
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.
2.
Intermittent Fasting versus Continuous Calorie Restriction: Which Is Better for Weight Loss?
Zhang, Q, Zhang, C, Wang, H, Ma, Z, Liu, D, Guan, X, Liu, Y, Fu, Y, Cui, M, Dong, J
Nutrients. 2022;14(9)
-
-
-
Free full text
Plain language summary
Obesity increases the risk of developing metabolic syndrome, diabetes, cardiovascular disease and associated comorbidities. Intermittent fasting (IF) and continuous calorie restriction (CCR) are fasting regimens known to reduce weight, which is at the heart of strategy in reducing obesity. IF and CCR restricts energy intake; however, CCR is harder to follow than IF. IF focuses more on time-restricted eating. This systematic review and meta-analysis examined the effectiveness of IF and CCR on body mass index (BMI), body weight, and metabolism in overweight and obese participants. This research showed that IF is significantly superior to CCR in weight loss in obese people. However, there was no difference in BMI between both regimens. There was a significant difference between IF and CCR for total cholesterol, triacylglycerol, and waist circumference. Further larger long-term robust studies are required to evaluate the effectiveness of different fasting regimens due to the high heterogeneity in this research. Healthcare professionals can use the results of this study to distinguish the weight loss effects between different fasting regimens.
Abstract
We conducted a systematic review and meta-analysis of randomized clinical trials and pilot trial studies to compare the effectiveness of intermittent fasting (IF) and continuous calorie restriction (CCR) in overweight and obese people. The parameters included body mass index (BMI), body weight, and other metabolism-related indicators. A systematic search in PubMed, Embase, Cochrane Library, and Web of Science was conducted up to January 2022. Standardized mean differences (SMDs) with 95% confidence intervals (CIs) were used to measure the effectiveness. Publication bias was assessed using Egger's test. The stability of the results was evaluated using sensitivity analyses. The significance of body weight change (SMD = -0.21, 95% CI (-0.40, -0.02) p = 0.028) was more significant after IF than CCR. There was no significant difference in BMI (SMD = 0.02, 95% CI (-0.16, 0.20) p = 0.848) between IF and CCR. These findings suggest that IF may be superior to CCR for weight loss in some respects.
3.
Effects of Intermittent Energy Restriction Combined with a Mediterranean Diet on Reducing Visceral Adiposity: A Randomized Active Comparator Pilot Study.
Panizza, CE, Lim, U, Yonemori, KM, Cassel, KD, Wilkens, LR, Harvie, MN, Maskarinec, G, Delp, EJ, Lampe, JW, Shepherd, JA, et al
Nutrients. 2019;11(6)
-
-
-
Free full text
Plain language summary
Excess adiposity is known to contribute to many metabolic diseases. Intermittent energy restriction (IER) has emerged as a favourable method of calorie reduction, and combining IER with the Mediterranean diet has shown promising results for reducing body fat and improving insulin resistance. The aim of this pilot study was to explore efficacy of an IER and Mediterranean diet in adiposity reduction in 60 Japanese Americans. Participants were randomised to either consume the IER + Mediterranean diet (22) or a control anti-hypertension diet (26) for 12 weeks. At baseline and 12-weeks, visceral adipose tissue and total fat mass were measured. Phone check-ins were completed weekly for the 12-weeks and both groups had equivalent dietetic support. This study found significant reductions in total fat mass in the IER + Mediterranean group compared with the control group, and found diet adherence to be high. Based on these results, the authors conclude the IER and Mediterranean diet combined can lower total adiposity and potentially improve liver function among Japanese Americans.
Abstract
Intermittent energy restriction combined with a Mediterranean diet (IER+MED) has shown promise to reduce body fat and insulin resistance. In the Multiethnic Cohort Adiposity Phenotype Study, Japanese Americans had the highest visceral adipose tissue (VAT) when adjusting for total adiposity. We conducted this pilot study to demonstrate feasibility and explore efficacy of following IER+MED for 12 weeks to reduce VAT among East Asians in Hawaii. Sixty volunteers (aged 35-55, BMI 25-40 kg/m2, VAT ≥ 90 cm2 for men and ≥ 80 cm2 for women) were randomized to IER+MED (two consecutive days with 70% energy restriction and 5 days euenergetic MED) or an active comparator (euenergetic Dietary Approaches to Stop Hypertension (DASH) diet). Participants and clinic staff (except dietitians) were blinded to group assignments. IER+MED had significantly larger reductions in DXA-measured VAT and total fat mass (-22.6 ± 3.6 cm2 and -3.3 ± 0.4 kg, respectively) vs. DASH (-10.7 ± 3.5 cm2 and -1.6 ± 0.4 kg) (p = 0.02 and p = 0.005). However, after adjusting for total fat mass, change in VAT was not statistically different between groups; whereas, improvement in alanine transaminase remained significantly greater for IER+MED vs. DASH (-16.2 ± 3.8 U/L vs. -4.0 ± 3.6 U/L, respectively, p = 0.02). Attrition rate was 10%, and participants adhered well to study prescriptions with no reported major adverse effect. Results demonstrate IER+MED is acceptable, lowers visceral and total adiposity among East Asian Americans, and may improve liver function more effectively than a healthful diet pattern. ClinicalTrials.gov Identifier: NCT03639350.