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

Examining the Optimal Exercise Frequency for Alleviating Liver Fat in Centrally Obese Adults With Non-Alcoholic Fatty Liver Disease (NAFLD): A Comparative Randomized Controlled Trial

This study aims to examine the comparative effectiveness of different exercise frequencies (once-a-week vs. thrice-a-week) for reducing liver fat in centrally obese adults with non-alcoholic fatty liver disease (NAFLD), with weekly exercise volumes aligned with the World Health Organization's physical activity recommendations.

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:

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

Exclusion Criteria:

1. Regular exercise training (>3 sessions of >60 min of moderate-intensity exercise training weekly) in the past 6 months;
2. Medical history of cardiovascular disease, chronic pulmonary or kidney disease, heart failure, cancer, and/or liver disease except NAFLD;
3. Somatic conditions that limit exercise participation (e.g., limb loss);
4. Impaired mobility due to chronic disease (e.g., chronic arthritis/osteoarthritis, neurological, musculoskeletal, and autoimmune diseases);
5. Daily smoking habit;
6. Excess alcohol consumption (daily ≥20 g of alcohol for men and ≥10 g for women) in the past 1 year;
7. Consumption of certain drugs (e.g., tamoxifen and estrogen) known to be secondary causes of steatosis;
8. 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);
9. Physical changes that considerably affect body composition and weight (e.g., anorexia nervosa, bulimia nervosa, prolonged gastrointestinal and digestive disorders) during the study period.