Time-Restricted Eating versus Calorie Restriction for the management of Metabolic Syndrome: Systematic Review and Meta-analysis

Background: Metabolic syndrome is a growing global health concern associated with increased risk of cardiovascular disease and type 2 diabetes. Among various dietary interventions, Time-Restricted Eating (TRE) and Calorie Restriction (CR) are two prominent strategies used to manage metabolic parameters. However, the comparative efficacy of these two approaches remains unclear. Objective: To systematically compare the effects of Time-Restricted Eating versus Calorie Restriction on metabolic syndrome outcomes through a meta-analysis of available clinical studies. Methods: A comprehensive literature search was conducted across PubMed, Scopus, Web of Science, and Cochrane Library for studies published up to June 2025. Studies comparing TRE and CR in adults with metabolic syndrome were included. Data were extracted and analyzed using random-effects meta-analysis, with standardized mean difference (SMD) as the outcome measure. Heterogeneity, publication bias, and study quality were assessed. Results: A total of 9 studies were included. The pooled estimate showed a significant benefit of TRE over CR for improving metabolic outcomes (SMD = −0.396; 95% CI: −0.479 to −0.313; p < 0.001). No significant heterogeneity was detected (I² = 0%, p = 1.000). Publication bias tests were non-significant, and no studies were found to be outliers or highly influential. Conclusion: Time-Restricted Eating is more effective than traditional Calorie Restriction in improving metabolic parameters among individuals with metabolic syndrome. TRE may represent a promising, sustainable dietary strategy with strong physiological and behavioral advantages. Further high-quality, long-term trials are needed to confirm these findings and explore clinical outcomes.