Background: The effect of soy products on the weight of overweight or obese people is controversial, so we aimed to conduct a systematic review and a meta-analysis of published randomized controlled trials to analyze whether supplementation with soy products can help them to lose weight.
Methods: The relevant data before January 2019 in PubMed, Embase and Cochrane Library were searched. A random-effect model was adopted to calculate the weighted average difference of net changes of body weight, body mass index (BMI), body fat percentage, fat mass, waist circumference, etc. Results: A total of 22 trials (870 overweight or obese participants) were reflected in the present meta-analysis. Analysis showed that soy products significantly reduced body weight, BMI, body fat percent and waist circumference in overweight or obese Asian populations (-0.37 kg, P = 0.010; -0.27 kg/m2, P = 0.042; -0.36%, P = 0.032; -0.35 cm, P = 0.049) and more significant effects were observed in non-menopausal women reduced body weight (-0.59 kg, P = 0.041), BMI (-0.59, P = 0.041) and waist circumference (-0.59 cm, P = 0.041) in overweight or obese populations.
Conclusion: This meta-analysis showed that soy products have weight loss effects, mainly due to soy protein, isoflavone and soy fiber.
Keywords: BMI; isoflavones; soy fiber; soy products; soy protein; weight.