Impact of weight loss and reduction of ultra-processed foods on liver fat content in MASLD: A randomized controlled trial

BACKGROUND & AIMS: Dietary interventions are a cornerstone of management for metabolic dysfunction-associated steatotic liver disease (MASLD). However, it remains unclear whether specific dietary patterns confer benefits beyond weight loss. We aimed to compare the effects of different dietary strategies on liver fat and metabolic health in patients with MASLD. METHODS: We conducted a 6-month, three-arm, parallel-group randomized controlled trial including patients with MASLD and overweight or obesity who were naïve to structured nutritional counselling. Participants were randomized to Mediterranean diet (MeD), low-carbohydrate, high-protein diet (LCHO), or standard nutritional recommendations. Liver fat content was assessed by controlled attenuation parameter (CAP). Secondary outcomes included changes in anthropometric and metabolic parameters, body composition, and ultra-processed food (UPF) consumption. Structural equation modelling was used to investigate pathways linking dietary allocation, weight loss, and UPF intake with changes in CAP. RESULTS: Of 173 enrolled participants, 148 (85.5%) completed the study. CAP decreased significantly within the LCHO and control groups (Δ -19.5 [-48.8 to 8.0], p = 0.004 and -11.0 [-32.0 to 12.0], p