Objective: To study the effects of soy protein supplement on overweight and obese population.
Methods: Randomized controlled trials (RCT) published from January 1988 to May 2012 observing the effect of soy protein supplement on overweight and obese population were collected. Meta-analysis was applied to estimate the standardized mean difference (WMD) and 95% confidence interval (95% CI).
Results: Among 13 RCTs, the number of the studies observing change of body weight, body mass index (BMI), fat mass and waist circumference were 12, 7, 7 and 11, respectively. Compared with the control group, the combined WMD (95% CI) of soy protein supplemented was - 1.04 kg [( -1.97) - ( -0.11)], -0.19 kg/m2 [(-0.41) - (0.02)], -0.99 kg [(-1.73) - (-0.24)] and - 0.94 cm [(-1.66) - (-0.21)], respectively. However, the protective effect of soy protein was only observed among studies conducted in Western population, but not in Asian population.
Conclusion: Soy protein supplementation significantly decreased body weight, fat mass and waist circumference in overweight and obese population.