Introduction: Metabolic-associated fatty liver disease (MAFLD) is the most prevalent liver disease, affecting ~25% of people globally and ~80% of individuals with obesity. This position statement aimed to i) examine evidence for exercise in the management of MAFLD, and based on this, ii) provide evidence- and consensus-based recommendations for exercise therapy in MAFLD management.
Method: A systematic search for systematic reviews with meta-analyses was conducted from database inception to June 2023 across seven electronic databases. The evidence generated by extraction and collation of literature was reviewed and graded. Consensus on the content and recommendations of the position statement was reached through an iterative process involving the multidisciplinary authorship team.
Results: Five overarching evidence statements were defined. Grade A evidence was conferred for aerobic exercise for: 1) moderate reduction in hepatic steatosis (2-4%); 2) small reductions in body mass index (~0.85-0.97 kg/m2) and; 3) clinically meaningful improvement in cardiorespiratory fitness (~3.5-8.0 mL/kg/min), with high-certainty of evidence. Emerging evidence suggested that high-intensity interval training (HIIT) may be comparable to moderate-intensity continuous training for reducing hepatic steatosis. Evidence for the efficacy of resistance training on reducing hepatic steatosis was uncertain. There was minimal data to inform the effect of exercise on histological features of MAFLD. Exercise prescription recommendations were developed for four management goals: 1) reduction in hepatic steatosis; 2) reduction in central adiposity; 3) improvement in body mass and 4) improvement in cardiorespiratory fitness.
Conclusion: Evidence indicated that 150-240 min/week of at least moderate-intensity aerobic exercise can reduce hepatic steatosis by ~2-4%; but as little as 135 min/week has been shown to be effective. There does not appear to be an intensity-dependent benefit as long as the recommended exercise amount is achieved. This dose of exercise is likely to improve central adiposity, cardiorespiratory fitness and cardiometabolic health, irrespective of weight loss.