Objective: The main objective of this study was to assess the influence of soy protein intake and weight training on resting energy expenditure (REE) in postmenopausal women.
Methods: This 160-week clinical trial enrolled 60 women, with a mean age of 59 (7) years, allocated into four groups: G1 (soy protein plus exercise), G2 (placebo plus exercise), G3 (soy protein and no exercise) and G4 (placebo and no exercise). Soy protein and placebo (maltodextrin) were randomly distributed in powder form in servings of 25 grams/day. Ten weight exercises were performed, three times a week, with three sets of 8-12 repetitions per exercise per session, at a load of 60-80% of the one-repetition maximum (1RM). The REE was calculated from the O2 and CO2 values obtained by indirect calorimetry (Quinton QMC), performed for 30 minutes under controlled temperature and humidity. For statistical analysis, ANOVA, Student t test and multiple regression were performed with the Stata 9.2 software package. Significance was set at p<0.05.
Results: The study sample was homogeneous with regard to all variables. Significant increases in REE (p <0.05) were detected in G1 (158 kcal/day, 17%) and G2 (110 kcal/day, 9%), whereas a 4% decrease was detected in G4 (p<0.05).
Conclusion: Weight training is a determining factor for increased resting energy expenditure in postmenopausal women. This effect can be boosted by dietary consumption of soy protein.