The Effect of a Soya-Based Dietary Fibre Beverage on Adiposity and Systemic Inflammatory Markers Among Overweight Adults: A Cluster-Randomized Controlled Trial

Background: The increasing prevalence of overweight and obesity highlights the need for practical and sustainable dietary strategies for weight management. Although dietary fibre intake is associated with improved satiety and metabolic health, achieving recommended intake levels through whole foods alone remains challenging. Evidence supporting convenient, ready-to-consume fibre beverages in free-living overweight adults is also limited. Therefore, this study evaluated the effects of a soya-based dietary fibre beverage (SBB) on body composition and metabolic parameters in overweight adults. Methods: A 12-week parallel, cluster-randomized controlled trial was conducted on overweight university students and staff. An intervention group (IG) (n = 21) consumed the soya-based dietary fibre twice daily for 12 weeks, while the control group (CG) (n = 21) continued their habitual diet. Results: Significant group × time interactions were observed for body weight (p < 0.001), BMI (p = 0.021), waist circumference (p = 0.046), waist-to-hip ratio (p = 0.042), and body fat percentage (p = 0.004). The IG showed reductions in body weight (−1.12 kg), waist circumference (−4.29 cm), and body fat percentage (−0.73%), whereas the CG demonstrated minimal changes. No significant changes were observed in fasting glucose, lipid profile, CRP, or IL-6, suggesting no clinically significant adverse biochemical changes during the intervention period and supporting its short-term tolerability. Dietary analysis confirmed a marked increase in fibre intake in the IG (~50 g/day), indicating good adherence to the intervention. Conclusions: SBB supplementation improved body composition and central adiposity without affecting systemic inflammatory biomarkers and may represent a practical dietary approach for weight management in free-living overweight adults. Further studies are needed to confirm its long-term efficacy and safety.