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

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). 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.