The Effect of Early Time-Restricted Eating vs Later Time-Restricted Eating on Weight Loss and Metabolic Health

Abstract Context It remains controversial whether the choice of the daily eating window early or later in time-restricted eating (TRE) intervention (early or later TRE) has different effects on weight loss and metabolic health. Objective A network meta-analysis was performed to evaluate the efficacy between early and later TRE in adults with obesity or overweight. Methods We searched PubMed, Embase, Web of Science, and Cochrane Library for randomized controlled trials (RCTs) published until October 16, 2022. We conducted a network meta-analysis to evaluate the efficacy of early and later TRE on body weight and metabolic parameters, including glycemic metabolism, blood pressure, and lipid profiles. Results Twelve RCTs with 730 obese or overweight adults were included in this meta-analysis. Early TRE and later TRE both elicited moderate reductions in body weight and insulin resistance (IR) (homeostasis model assessment of IR) when compared to non-TRE. Interestingly, early TRE showed more effectiveness than later TRE in improving IR (early vs later TRE: −0.44; 95% CI, −0.86 to −0.02; P < .05), whereas no statistically significant difference was detected in weight loss (early vs later TRE: −0.31 kg; 95% CI, −1.15 to 0.53 kg; P >.05). In addition, early TRE rather than later TRE showed significant benefits in glycemic metabolism and blood pressure when compared to non-TRE. No significant differences between early and later TRE were observed for fasting blood glucose, blood pressure, and lipid profiles. Conclusion This meta-analysis suggests that people may choose early TRE for more effective weight management and metabolic benefits. Nevertheless, further large-scale RCTs are warranted to verify our findings.