Structured Exercise Interventions and Hepatic–Metabolic Outcomes in Adults with MASLD: A Narrative Review of Randomized Controlled Trials

Metabolic dysfunction-associated steatotic liver disease (MASLD, introduced in 2023), formerly termed non-alcoholic fatty liver disease (NAFLD), is a leading cause of chronic liver disease worldwide and is closely linked to obesity, insulin resistance, and cardiometabolic dysfunction. Exercise is widely recommended as a cornerstone of MASLD management; however, the magnitude of its hepatic and metabolic benefits and the underlying molecular mechanisms remain incompletely defined. We aim to synthesize evidence from randomized controlled trials assessing how structured exercise interventions influence hepatic steatosis and metabolic dysfunction in adults with MASLD. A targeted search of PubMed from database inception to February 2025 identified eligible trials, of which eleven were included in the qualitative synthesis. Across studies, aerobic and resistance exercise interventions were consistently associated with reductions in hepatic fat content, improvements in plasma lipid profiles and liver enzyme concentrations, and enhanced indices of insulin sensitivity, frequently occurring independently of substantial weight loss. Mechanistically, exercise-induced activation of pathways related to mitochondrial function, lipid oxidation, inflammation modulation, and insulin signaling likely contributes to these benefits. Despite heterogeneity in intervention design, duration, and outcome assessment, the collective evidence supports structured exercise as an effective non-pharmacological strategy for improving hepatic steatosis and metabolic dysfunction in MASLD. Future studies integrating molecular biomarkers with clinical endpoints are warranted to refine exercise prescriptions and elucidate mechanisms of therapeutic response.