Umbrella review of time-restricted eating on weight loss, fasting blood glucose, and lipid profile.

Abstract

A growing number of systematic reviews with meta-analyses have examined the effectiveness of time-restricted eating (TRE) in reducing weight and improving fasting blood glucose and lipid profiles. However, mixed results have been found, and its effectiveness remains uncertain. This umbrella review aimed to summarize systematic reviews that (1) examine the effects of TRE on weight loss, fasting blood glucose, total cholesterol, triglycerides, high-density-lipoprotein cholesterol (HDL-C) and low-density-lipoprotein cholesterol (LDL-C) in individuals with overweight and obesity; and (2) compare the effect sizes on these outcomes between conventional TRE and Ramadan fasting. A total of 11 databases were searched from inception until March 11, 2022. Two independent reviewers performed article selection, data extraction, and quality assessment. Seven systematic reviews with 30 unique meta-analyses involving 7231 participants from 184 primary studies were included. The quality of each review was evaluated as moderate (14.3%) or critically low (85.7%) according to the Assessment of Multiple Systematic Reviews 2. The degree of overlap was rated as slight for all outcomes (corrected cover area = 1.04%-4.27%). Meta-analyses at the meta-data level suggest that TRE is beneficial for reducing weight (P = .006) and fasting blood glucose (P < .01). Meta-analyses at the primary study level suggest that the effect on LGL-C was significant (P = .03). Subgroup analyses revealed greater effects in lowering fasting blood glucose, total cholesterol, and LDL-C from Ramadan fasting than from conventional TRE. The credibility of evidence was rated as suggestive (3.3%), weak (36.7%) or nonsignificant (60%) using a classification method. TRE may complement usual care and reduce body weight and fasting blood glucose. Rigorous randomized controlled trials with long-term assessments in a wide range of populations are warranted. PROSPERO registration no. CRD42022325657.