Effects of Time-Restricted Eating on Metabolic and Hepatic Outcomes in Non-Diabetic Adults with Metabolic Dysfunction-Associated Steatotic Liver Disease: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Introduction. Time-restricted eating (TRE) is a circadian-aligned dietary intervention for the management of metabolic disorders. However, its efficacy in non-diabetic adults with metabolic dysfunction-associated steatotic liver disease (MASLD), previously known as non-alcoholic fatty liver disease, remains unclear. This study aimed to evaluate the effects of TRE on hepatic and metabolic outcomes in this population. Methods. A systematic review and meta-analysis of randomized controlled trials (RCTs) were conducted from database inception through December 2025 across PubMed, Ovid, Web of Science, and trial registries. The searches were conducted between September and December 2025. Eligible studies enrolled non-diabetic adults with MASLD (hepatic steatosis >5%) undergoing TRE for ≥4 weeks. Random-effects models were used to pool mean differences (MDs) or standardized MDs with 95% confidence intervals, and heterogeneity was assessed using the I2 statistic. Certainty of evidence was evaluated using the Grading of Recommendations Assessment, Development, and Evaluation. Primary outcomes were liver fat content, alanine aminotransferase (ALT), aspartate aminotransferase (AST), and insulin resistance (HOMA-IR). Secondary outcomes included anthropometric indices, lipid profile, fasting glucose, inflammatory markers, adherence, adverse events, and dropout rates. Results. Five RCTs (n = 291) from China and Iran met the inclusion criteria. TRE modestly reduced serum ALT levels compared to non-TRE controls (MD = -7.28; 95% CI, -12.27 to -2.29; p = 0.004; I2 = 50%). No significant differences were observed in liver fat content, AST, or HOMA-IR. Among secondary outcomes, only body mass index demonstrated a small, but significant improvement (MD = -0.87 kg/m2; 95% CI, -1.57 to -0.18; p = 0.01; I2 = 22%). Lipid parameters, fasting glucose, and inflammatory markers showed no consistent benefit. Clinical and methodological heterogeneity was substantial. Overall certainty of evidence ranged from very low to low. Conclusions. In non-diabetic adults with MASLD, TRE yields modest improvements in ALT and BMI but does not significantly improve hepatic steatosis or core metabolic indices. Evidence remains limited because of small sample sizes, short intervention durations, and substantial heterogeneity. Future RCTs with standardized TRE protocols and longer follow-up are required to establish clinical efficacy and strengthen evidence certainty.