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

Abstract

Objective: 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).Methods: 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. Metaregression analysis was presented as weighted mean differences of body weight loss. Results: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. Conclusions: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.

Timing of energy intake and the therapeutic potential of intermittent fasting and time-restricted eating in NAFLD

“…These findings may be related to inaccurate food diary reporting in TRE trials or due to as yet unknown physiological mechanisms. Meta-analyses of RCTs has corroborated these observations showing that IF is likely to be the most effective dietary weight loss strategy, followed by CCR, and then TRE 118. Nonetheless, despite relatively modest weight reductions, TRE is associated with significant and often disproportionate improvements in cardiometabolic health.…”

“…TRE may, therefore, be a more attractive dietary strategy for some individuals by allowing them to simply ‘watch the clock’ rather than meticulously calculate ongoing calorie consumption. This is demonstrated in meta-analysis of 24 RCTs where study retention rates used as a gross indicator of compliance were highest for TRE (94%), followed by 5:2 diet (88%) and ADF (85%) 118…”

“…However, in head-to-head trials, the degree of weight loss is typically equivalent to that observed with continuous calorie restriction (CCR). This is substantiated through network meta-analysis of 24 studies showing that IF regimens result in a similar degree of weight loss to CCR (mean difference: −0.26 kg over a period of 2–26 weeks) 118. There is no clear evidence to suggest the relative superiority of either 5:2 or ADF regimens 118.…”

Does Timing Matter? A Narrative Review of Intermittent Fasting Variants and Their Effects on Bodyweight and Body Composition

“…Varady and Gabel reported ADF-mediated weight loss ranging from ~3–7% in trials lasting approximately two to six months [ 11 ]. A meta-analysis by Elortegui Pascual et al [ 12 ], including 24 randomized controlled trials (RCTs), found that ADF resulted in greater weight loss than TWF and TRE. However, it was noted that the degree of weight loss between the diets was not statistically significant.…”

Chrononutrition in the context of Ramadan: Potential implications

“…IF comes in different forms. More common IF regimens include alternate day fasting, time restricted eating (TRE‐also referred to as time restricted fasting or TRF, especially when referring to animal studies) and whole day fasting 10–12 (Figure 1).…”