Optimal Exercise Frequency to Reduce Liver Fat in Centrally Obese Adults With Non-Alcoholic Fatty Liver Disease

This study is a three-arm randomized controlled trial. Participants will be randomly allocated to the once-a-week exercise group, thrice-a-week exercise group, or usual care control group. The exercise intervention groups will receive once-a-week or thrice-a-week exercise (with matched weekly exercise volumes). The usual care control group will receive general health education. All interventions will last for 4 months. Outcome measures will be examined at baseline, 4 months (post-intervention), and 10 months (6-month follow-up).

Inclusion criteria

• Cantonese, Mandarin, or English speaking Chinese;
• Aged 18-69;
• Male or female;
• Centrally obese according to the Asian-specific cut-off (waist circumference ≥90 cm for males; ≥80 cm for females) and with BMI ≥23;
• With NAFLD (defined as >5% intrahepatic triglycerides assessed by 1H-MRS);
• Willing to participate in exercise training to improve NAFLD.

Exclusion criteria

• Regular exercise training (>3 sessions of >60 min of moderate-intensity exercise training weekly) in the past 6 months;
• Medical history of cardiovascular disease, chronic pulmonary or kidney disease, heart failure, cancer, and/or liver disease except NAFLD;
• Somatic conditions that limit exercise participation (e.g., limb loss);
• Impaired mobility due to chronic disease (e.g., chronic arthritis/osteoarthritis, neurological, musculoskeletal, and autoimmune diseases);
• Daily smoking habit;
• Excess alcohol consumption (daily ≥20 g of alcohol for men and ≥10 g for women) in the past 1 year;
• Consumption of certain drugs (e.g., tamoxifen and estrogen) known to be secondary causes of steatosis;
• Surgery, therapy, or medication for obesity or weight loss in the past 6 months (e.g., gastric bypass, gastric band, sleeve gastrectomy, gastric reduction duodenal switch, or dietitian-prescribed dietary program);
• Physical changes that considerably affect body composition and weight (e.g., anorexia nervosa, bulimia nervosa, prolonged gastrointestinal and digestive disorders) during the study period.