The Effect of Time-Restricted Eating Combined with Exercise on Body Composition and Metabolic Health: A Systematic Review and Meta-Analysis

BACKGROUND: Time-restricted eating (TRE) is increasingly popular, but its benefits in combination with exercise still need to be determined. OBJECTIVES: This systematic review and meta-analysis aimed to evaluate the efficacy of TRE combined with exercise compared with control diet with exercise in improving the body composition and metabolic health of adults. METHODS: Five electronic databases were searched for relevant studies. Randomized controlled trials (RCTs) examining the effect of TRE combined with exercise on body composition and metabolic health in adults were included. All results in the meta-analysis are reported as mean difference (MD) with 95% confidence interval (CI). Study quality was assessed using the revised Cochrane Risk of Bias Tool and Grading of Recommendations Assessment, Development, and Evaluation assessment. RESULTS: In total, 19 RCTs comprising 568 participants were included in this systematic review and meta-analysis. TRE combined with exercise likely reduced the participants' body mass (MD: -1.86 kg; 95% CI: -2.75, -0.97 kg) and fat mass (MD: -1.52 kg; 95% CI: -2.07, -0.97 kg) when compared with the control diet with exercise. In terms of metabolic health, the TRE combined with exercise group likely reduced triglycerides (MD: -13.38 mg/dL, 95% CI: -21.22, -5.54 mg/dL) and may result in a reduction in low-density lipoprotein (MD: -8.52 mg/dL; 95% CI: -11.72, -5.33 mg/dL) and a large reduction in leptin (MD: -0.67 ng/mL; 95% CI: -1.02, -0.33 ng/mL). However, TRE plus exercise exhibited no additional benefit on the glucose profile, including fasting glucose and insulin, and other lipid profiles, including total cholesterol and high-density lipoprotein concentrations, compared with the control group. CONCLUSIONS: Combining TRE with exercise may be more effective in reducing body weight and fat mass and improving lipid profile than control diet with exercise. Implementing this approach may benefit individuals aiming to achieve weight loss and enhance their metabolic well-being. This study was registered in PROSPERO as CRD42022353834.