Exercise-only interventions for metabolic dysfunction-associated steatotic liver disease: a systematic review and meta-analysis.

Metabolic dysfunction-associated steatotic liver disease (MASLD) is highly prevalent, and exercise is recommended as a first-line therapy. However, it remains unclear whether reductions in liver fat content are accompanied by consistent changes in other hepatic, metabolic, and anthropometric outcomes when exercise is evaluated in isolation. This review assessed the effects of different exercise modalities on these outcomes and the certainty of the evidence. Nine databases were searched from inception to January 2026. Randomized and nonrandomized studies comparing supervised exercise interventions (aerobic, resistance training, or high-intensity interval training) versus controls in individuals with MASLD were included. Studies combining exercise with diet or pharmacotherapy were excluded. Forty-one studies (n = 1517) were included; 24 were meta-analyzed. Resistance training was associated with reductions in liver fat content compared with control (standardized mean difference = -0.77, 95% confidence interval: -1.14 to -0.39), followed by moderate-intensity aerobic exercise (standardized mean difference = -0.50, 95% confidence interval: -0.95 to -0.04). High-intensity interval training showed no clear effect. Changes in liver enzymes were inconsistent, suggesting dissociation from liver fat responses. Moderate-intensity aerobic exercise improved transaminases and triglycerides, while resistance training improved fasting glucose and high-density lipoprotein cholesterol. Effects on BMI, body fat, and glycated hemoglobin were negligible. Certainty of evidence was low to very low. Exercise, particularly resistance training and moderate-intensity aerobic training, reduces liver fat in MASLD without consistent changes in adiposity-related outcomes. Low certainty of evidence precludes precise exercise recommendations. Well designed randomized trials are needed.