過体重の女性における大豆ベースのタンパク質が豊富なサプリメントの摂取が体組成と食行動に与える影響：ACOORH試験の二次解析

High-protein dietary strategies have been shown to support weight reduction and improve body composition during lifestyle interventions. However, evidence regarding long-term dietary adaptations and their association with body composition in overweight women remains limited. This secondary analysis of the ACOORH randomised controlled trial investigated whether a protein-rich soy-based meal replacement promotes sustained dietary protein intake and favourable body composition changes in female participants. Female participants from the multicentre ACOORH RCT with complete dietary records at baseline, week 12 and week 52 were included (n = 64). Participants received either a standardised lifestyle intervention alone or the same intervention combined with a protein-rich soy-yoghurt-honey meal replacement during the first 26 weeks. Dietary intake, body composition, physical activity and muscle strength were evaluated longitudinally. Between-group comparisons, repeated measures ANCOVA and exploratory correlation analyses were performed. Both groups significantly reduced daily energy intake during the first 12 weeks. However, only the intervention group increased body weight-adjusted protein intake (+0.22 ± 0.29 g/kg/day), resulting in a significant between-group difference ( = 0.004). The higher protein intake was maintained throughout the 52-week study despite discontinuation of meal replacement after week 26 ( < 0.001). Repeated measures ANCOVA demonstrated significantly greater improvements in body mass index ( = 0.04) and fat mass ( = 0.03) in the intervention group. At week 52, higher protein intake was significantly associated with lower body mass index (r = -0.253; = 0.04), lower fat mass (r = -0.321; = 0.01) and greater muscle strength (r = 0.292; = 0.02), whereas no association with physical activity was observed. Among overweight women participating in a structured lifestyle intervention, temporary supplementation with a protein-rich soy-based meal replacement was associated with sustained increases in dietary protein intake and more favourable long-term body composition. These findings support the concept that maintaining a higher protein intake during weight reduction may contribute to improved body composition outcomes. Larger prospective studies specifically designed to investigate sex-specific effects of protein-rich dietary interventions are warranted.