Obesity Reviews · Oct 22, 2026
Long-Term Exercise Training for Liver Enzymes and Liver Fat in Adults With Nonalcoholic Fatty Liver Disease: A Multilevel Dose-Response Meta-Analysis
By Li D, Cui Y, Li Z
OBJECTIVE: This study aimed to quantify long-term exercise effects on liver enzymes and liver fat content in adults with nonalcoholic fatty liver disease (NAFLD) and explore dose-response patterns and modifiers. METHODS: Four databases were searched through May 28, 2026. Three-level random-effects models accounted for dependent effect sizes and were supplemented by sampling variance-covariance models that explicitly addressed correlations arising from shared comparator groups. CR2 cluster-robust variance estimation was additionally used for small-sample robust inference. Robustness was further examined using influence, sensitivity, publication-bias, and trim-and-fill analyses. Subgroup, meta-regression, dose-response, and XGBoost-SHAP analyses were conducted. Risk of bias and certainty were assessed using RoB 2 and GRADE. RESULTS: Sixteen randomized controlled trials were included. Exercise was associated with lower ALT (MD = -6.01, 95% CI -11.88 to -0.15; p = 0.045) and liver fat content (SMD = -0.47, 95% CI -0.66 to -0.27; p < 0.001), whereas AST was not significant. After CR2 correction, liver fat remained significant, but ALT did not. Exploratory analyses suggested possible heterogeneity related to exercise frequency, intervention duration, age, and participant type, but these findings were limited by the small number of studies and multiple comparisons. A favorable cumulative dose near 16 h was near the data boundary, not a prescription target. CONCLUSION: Long-term exercise was associated with lower liver fat content in adults with NAFLD. ALT reduction remains possible but uncertain; AST evidence is insufficient, and dose-response findings require confirmation.