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

Abstract

Context: 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.

Objective: 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.

Data sources: A total of 11 databases were searched from inception until March 11, 2022.

Data extraction: Two independent reviewers performed article selection, data extraction, and quality assessment.

Data analysis: 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.

Conclusion: 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.

Systematic review registration: PROSPERO registration no. CRD42022325657.

Keywords: fasting blood glucose; lipid profile; time-restricted eating; umbrella review; weight.