Comparing caloric restriction regimens for effective weight management in adults: a systematic review and network meta-analysis.

Randomized controlled trials have confirmed the effectiveness of four prevalent caloric restriction regimens in reducing obesity-related health risks. However, there is no consensus on the optimal regimen for weight management in adults. We systematically searched PubMed, Embase, Web of Science, and Cochrane CENTRAL up to January 15, 2024, for randomized controlled trials (RCT) involving adults, evaluating the weight-loss effects of alternate day fasting (ADF), short-term fasting (STF), time-restricted eating (TRE), and continuous energy restriction (CER). The primary outcome was body weight, with secondary outcomes including BMI, fat mass, lean mass, waist circumference, fasting glucose, HOMA-IR, and adverse events. Bayesian network meta-analysis was conducted, ranking regimens using the surface under the cumulative ranking curve and the probability of being the best. Study quality was assessed using the Confidence in Network Meta-Analysis tool. Data from 47 RCTs (representing 3363 participants) were included. ADF showed the most significant body weight loss (Mean difference (MD): -3.42; 95% Confidence interval (CI): -4.28 to -2.55), followed by TRE (MD: -2.25; 95% CI: -2.92 to -1.59). STF (MD: -1.87; 95% CI: -3.32 to -0.56) and CER (MD: -1.59; 95% CI: -2.42 to -0.79) rank third and fourth, respectively. STF lead to decline in lean mass (MD: -1.26; 95% CI: -2.16, -0.47). TRE showed benefits on fasting glucose (MD: -2.98; 95% CI: -4.7, -1.26). Subgroup analysis revealed all four caloric restriction regimens likely lead to modest weight loss after 1-3 months, with ADF ranked highest, but by 4-6 months, varying degrees of weight regain occur, particularly with CER, while interventions lasting 7-12 months may result in effective weight loss, with TRE potentially ranking first during both the 4-6 months and 7-12 months periods. ADF showing fewer and shorter-lasting physical symptoms. All four included regiments were effective in reducing body weight, with ADF likely having the most significant impact. Each regimen likely leads to modest weight loss after 1-3 months, followed by weight regain by 4-6 months. However, interventions lasting 7-12 months achieve greater weight loss overall. PROSPERO: CRD42022382478.

Huang J ，Li Y ，Chen M ，Cai Z ，Cai Z ，Jiang Z ... -  《International Journal of Behavioral Nutrition and Physical Activity》

A meta-analysis comparing the effectiveness of alternate day fasting, the 5:2 diet, and time-restricted eating for weight loss.

The objective of this meta-analysis was to compare the effectiveness of different intermittent fasting (IF) regimens on weight loss, in the general population, and compare these to traditional caloric energy restriction (CER). Three databases were searched from 2011 to June 2021 for randomized controlled trials (RCTs) that assessed weight loss and IF, including alternate day fasting (ADF), the 5:2 diet, and time-restricted eating (TRE). A random effect network analysis was used to compare the effectiveness between the three regimens. Meta-regression analysis was presented as weighted mean differences of body weight loss. The exploratory random effects network analysis of 24 RCTs (n = 1768) ranked ADF as the most effective, followed by CER and TRE. The meta-analysis showed that IF regimens resulted in similar weight loss to CER (mean difference 0.26 kg, 95% CI: -0.31 to 0.84; p = 0.37). Compliance was generally high (>80%) in trials shorter than 3 months. The present meta-analysis concludes that IF is comparable to CER and a promising alternative for weight loss. Among the three regimens, ADF showed the highest effectiveness for weight loss, followed by CER and TRE. Further well-powered RCTs with longer durations of intervention are required to draw solid conclusions.

Elortegui Pascual P ，Rolands MR ，Eldridge AL ，Kassis A ，Mainardi F ，Lê KA ，Karagounis LG ，Gut P ，Varady KA ... -  《-》

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.

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.

Schroor MM ，Joris PJ ，Plat J ，Mensink RP ... -  《-》

Effects of Different Exercises Combined with Different Dietary Interventions on Body Composition: A Systematic Review and Network Meta-Analysis.

Xie Y ，Gu Y ，Li Z ，He B ，Zhang L ... -  《Nutrients》

Intermittent fasting for the prevention of cardiovascular disease.

Cardiovascular disease (CVD) is the leading cause of death worldwide. Lifestyle changes are at the forefront of preventing the disease. This includes advice such as increasing physical activity and having a healthy balanced diet to reduce risk factors. Intermittent fasting (IF) is a popular dietary plan involving restricting caloric intake to certain days in the week such as alternate day fasting and periodic fasting, and restricting intake to a number of hours in a given day, otherwise known as time-restricted feeding. IF is being researched for its benefits and many randomised controlled trials have looked at its benefits in preventing CVD. To determine the role of IF in preventing and reducing the risk of CVD in people with or without prior documented CVD. We conducted our search on 12 December 2019; we searched CENTRAL, MEDLINE and Embase. We also searched three trials registers and searched the reference lists of included papers. Systematic reviews were also viewed for additional studies. There was no language restriction applied. We included randomised controlled trials comparing IF to ad libitum feeding (eating at any time with no specific caloric restriction) or continuous energy restriction (CER). Participants had to be over the age of 18 and included those with and without cardiometabolic risk factors. Intermittent fasting was categorised into alternate-day fasting, modified alternate-day fasting, periodic fasting and time-restricted feeding. Five review authors independently selected studies for inclusion and extraction. Primary outcomes included all-cause mortality, cardiovascular mortality, stroke, myocardial infarction, and heart failure. Secondary outcomes include the absolute change in body weight, and glucose. Furthermore, side effects such as headaches and changes to the quality of life were also noted. For continuous data, pooled mean differences (MD) (with 95% confidence intervals (CIs)) were calculated. We contacted trial authors to obtain missing data. We used GRADE to assess the certainty of the evidence.  MAIN RESULTS: Our search yielded 39,165 records after the removal of duplicates. From this, 26 studies met our criteria, and 18 were included in the pooled analysis. The 18 studies included 1125 participants and observed outcomes ranging from four weeks to six months. No studies included data on all-cause mortality, cardiovascular mortality, stroke, myocardial infarction, and heart failure at any point during follow-up. Of quantitatively analysed data, seven studies compared IF with ab libitum feeding, eight studies compared IF with CER, and three studies compared IF with both ad libitum feeding and CER. Outcomes were reported at short term (≤ 3 months) and medium term (> 3 months to 12 months) follow-up. Body weight was reduced with IF compared to ad libitum feeding in the short term (MD -2.88 kg, 95% CI -3.96 to -1.80; 224 participants; 7 studies; low-certainty evidence). We are uncertain of the effect of IF when compared to CER in the short term (MD -0.88 kg, 95% CI -1.76 to 0.00; 719 participants; 10 studies; very low-certainty evidence) and there may be no effect in the medium term (MD -0.56 kg, 95% CI -1.68 to 0.56; 279 participants; 4 studies; low-certainty evidence). We are uncertain about the effect of IF on glucose when compared to ad libitum feeding in the short term (MD -0.03 mmol/L, 95% CI -0.26 to 0.19; 95 participants; 3 studies; very-low-certainty of evidence) and when compared to CER  in the short term: MD -0.02 mmol/L, 95% CI -0.16 to 0.12; 582 participants; 9 studies; very low-certainty; medium term: MD 0.01, 95% CI -0.10 to 0.11; 279 participants; 4 studies; low-certainty evidence). The changes in body weight and glucose were not deemed to be clinically significant. Four studies reported data on side effects, with some participants complaining of mild headaches. One study reported on the quality of life using the RAND SF-36 score. There was a modest increase in the physical component summary score. Intermittent fasting was seen to be superior to ad libitum feeding in reducing weight. However, this was not clinically significant. There was no significant clinical difference between IF and CER in improving cardiometabolic risk factors to reduce the risk of CVD. Further research is needed to understand the safety and risk-benefit analysis of IF in specific patient groups (e.g. patients with diabetes or eating disorders) as well as the effect on longer-term outcomes such as all-cause mortality and myocardial infarction.

Allaf M ，Elghazaly H ，Mohamed OG ，Fareen MFK ，Zaman S ，Salmasi AM ，Tsilidis K ，Dehghan A ... -  《-》