Effectiveness of a protein-supplemented very-low-calorie diet program for weight loss: a randomized controlled trial in South Korea.

Introduction: Weight-loss strategies through meal replacements are effective and sustainable options. However, few studies have assessed their effects on weight loss including body composition through protein-supplemented meal replacements targeting the Asian population, including Koreans. This study aimed to assess the effectiveness and safety of a protein-supplemented very-low-calorie diet (PSVLCD) for weight reduction and changes in body composition in individuals with obesity over a 12-month long-term period. Methods: In total, 106 participants with obesity were randomly assigned to a PSVLCD or control group (food-based calorie-restricted diet). Body weight, waist circumference, body composition, and blood marker levels were measured throughout the study. Statistical analyses were performed to compare outcomes between the groups. Results: Among the 106 participants, 84 completed the 12-month follow-up. Intention-to-treat analysis showed that the mean weight loss from baseline to 12 months was -6.86 kg (8.21% of baseline weight) in the PSVLCD group and - 4.66 kg (5.47% of initial body weight) in the control group; the difference was -2.20 kg with a marginally significant interval (95% confidence interval [CI], -4.90; 0.50). Waist circumference (-8.35 cm vs. -4.85 cm; mean difference, -3.49 cm; 95% CI, -6.48 to -0.50) and visceral fat area (-28.28 cm Discussion: The PSVLCD group demonstrated a substantial initial reduction in waist circumference that was sustained over the study period, alongside a marginally significant decrease in weight. These findings suggest that a protein-supplemented very-low-calorie diet may be an effective strategy for long-term weight management and body composition improvement in individuals with obesity. Clinical trial registration: ClinicalTrials.gov, identififer NCT04597788.