Soy compared to casein meal replacement shakes with energy-restricted diets for obese women: randomized controlled trial

Randomized, Double-Blind, Controlled, Comparative Trial of Formula Food Containing Soy Protein vs. Milk Protein in Visceral Fat Obesity - FLAVO Study -

“…13,19, 20 Anderson et al compared the visceral fat area as estimated on CT in obese women who consumed soy and casein shakes as part of a calorie-restricted diet for 21 weeks. 21 Both were effective in reducing the visceral fat area, and there was no significant difference between the groups. High-intensity weight-loss interventions may decrease the likelihood of detecting significant differences between experimental arms.…”

Energy restriction only slightly influences protein metabolism in obese rats, whatever the level of protein and its source in the diet

“…Our initial hypothesis was that under conditions of energy deficit, the source of proteins might limit losses of lean body mass, especially when combining W proteins providing a massive afflux of leucine, which could stimulate protein anabolism, and C to supply amino acids throughout the postprandial anabolic window. 48,49 In the literature, differences between C and W proteins, or caseins and S proteins, in sustaining lean mass during energy restriction, were not observed, 11,50 although Adechian et al 51 reported a higher post-absorptive FSR in 40% restricted rats fed C than in those receiving W proteins, a result that was linked to a higher leucine plasma concentration in the C group. During our study, we also observed differences in amino-acid concentrations, including those of leucine, but without there being any impact on protein anabolism.…”

Soy intake is related to a lower body mass index in adult women

“…Despite some positive weight loss findings during interventions [15;16;18], the evidence from randomized trials indicates little effect of soy on body weight [5;10;17-21]. In particular, a well-controlled trial of a soy shake compared to a casein shake showed not difference in weight loss by assigned group [5]. The discrepancies across studies may be due to different types of soy or supplements consumed by the study subjects [28].…”

“…Because pharmacotherapy has limited effectiveness [2], nutritional strategies for weight management are of great interest. Due to its high protein and low cholesterol content, soy is often used as a meal replacement or dietary component in weight loss regimens [3][4][5]. In addition to lowering blood lipids [6], soy or its components may assist in weight control [5; 7], but is not clear whether the source of dietary protein plays a role in the regulation of food intake and body weight [8].…”