Anti-Obesity Effects of Soy Peptides In Vivo: A Meta-Analysis of Randomized Controlled Trials

Soybean peptides have been implicated in reducing body weight (BW); however, their efficacy for weight loss remains ambiguous. This study aimed to evaluate the effects of soybean peptides on BW outcomes via meta-analysis. To identify randomized controlled trials (RCTs) from January 2000 to June 2025, numerous databases (PubMed, Embase, Web of Science, and Cochrane Library) were searched comprehensively. Studies comparing the impact of different soybean peptide interventions on weight reduction were included. The weighted mean difference (WMD) and 95% confidence interval (CI) were synthesized. Surface under the cumulative ranking curve (SUCRA) determined the intervention rankings, and 18 RCTs met the inclusion criteria. Overall, soybean peptides significantly decreased BW (WMD = −1.96 g, 95% CI: −3.52, −0.40; p < 0.00001), BW gain (BWG), and body mass index (BMI). Subgroup analyses confirmed lowering of BW in both humans (WMD = −12.71 g, 95% CI: −30.42, 5.00; p < 0.00001) and mice (WMD = −1.73 g, 95% CI: −3.44, −0.03; p < 0.00001). The above results indicate that soy peptides contribute significantly to weight loss.