Regenerative Changes in Resting Energy Balance Demonstrating Metabolic Efficiency and Body Composition Normalization

Abstract

Resting metabolism plays a critical role in healthy weight management. Metabolic adaptations in response to lifestyle cues induce acclimatization of factors involved in resting state energy homeostasis. PURPOSE: To determine the effects of dietary modification and exercise intensity on resting energy metabolism and body composition in sedentary female cohort. METHODS: Subjects (n=46) with >25% fat mass participated in 10-weeks of 200 kcal·24 h-1 caloric deficit, adherence to whole-foods, plant-based diet, and randomization into three exercise groups. Exercise intensity levels were set by respiratory exchange ratio (RER) ranges determined through submaximal VO2-uptake treadmill test; Low: RER=0.75 (n=16), Moderate: RER=0.85 (n=16), High RER=0.95 (n=14). Resting metabolic rate (RMR) variables—respiratory quotient (RQ), VO2, VCO2, resting energy expenditure (REE), and macronutrient substrate oxidation rates (KCHO, KFAT)—were measured using indirect calorimetry at pre and post treatment stages with whole-body air displacement plethysmography to obtain body composition profiles. One-way ANOVA was performed to evaluate mean changes in resting energy metabolism and body composition. RESULTS: Significant differences in RQ and VCO2 were noted between groups (F 1,46=7.88, p=.001; F 1,46=3.51, p=.039, respectively). Significant differences in KCHO and KFAT substrate oxidation rates were noted between groups likewise (F 1,46=5.74, p=.006; F 1,46=5.05, p=.011, respectively). Changes in total body mass showed significant differences (F 1,46=6.39, p=.004). The most positive improvements in metabolic efficiency variables were appreciated in the low and moderate intensity groups in post hoc analysis. CONCLUSION: The combination of modest caloric adjustment, adherence to plant-based diet, and participating in a low or moderate intensity exercise program confers positive changes in metabolic status and corrective energy homeostasis that promotes effective body composition normalization.