Time-restricted eating with calorie restriction on weight loss and cardiometabolic risk: a systematic review and meta-analysis

The effect of time-restricted eating (TRE) has been summarized in previous studies, but its benefits in combination with calorie restriction (CR) still need to be determined. The present meta-analysis aimed to evaluate the efficacy of TRE with CR on weight loss and cardiometabolic risk. PubMed, Embase, Cochrane Library, and gray literature databases were searched from inception to October 18, 2022, for potential randomized controlled trial (RCT) studies based on predefined inclusion and exclusion criteria. Body weight and other cardiometabolic risk factors were described as weighted mean difference (WMD) with a 95% confidence interval (CI). Eight RCTs involving 579 participants were enrolled in the present analysis. The pooled results showed that TRE with CR reduced the body weight, fat mass, and waist circumference significantly (WMD: -1.40, 95% CI: -1.81 to -1.00, and I2: 0%; WMD: -0.73, 95% CI: -1.39 to -0.07, and I2: 0%; WMD: -1.87, 95% CI: -3.47 to -0.26, and I2: 67.25%, respectively). However, compared with CR alone, TRE plus CR exhibited no significant benefit on the blood pressure, glucose profile, and lipid profile. Subgroup analysis suggested that early TRE is more effective in weight loss (WMD: -1.42, 95% CI: -1.84 to -1.01, and I2: 0%) and improving fat mass (WMD: -1.06, 95% CI: -1.91 to -0.22, and I2: 0%) than delayed or broader TRE when combined with CR. Although the combination of TRE and CR can effectively decrease body weight, fat mass, and waist circumference, the long-term effects, particularly those on cardiometabolic risk in participants with chronic cardiovascular disease and diabetes, remain to be explored.