The Acute Consumption of an Isovolumic Water or Protein Shake Affects Body Composition as Determined via a Multi-Frequency Bioelectrical Impedance Analysis

Abstract

Introduction: The purpose of this study was to examine the effects of consuming either591.5 mL of water or 591.5 mL of isovolumic protein shake (160 kcal, 3 g fat, 4 g carbohydrate, 30 g protein) on indices of body composition. Methods: Forty-two recreationally active men (n=13) and women (n=29) (mean±SD – height 168±10 cm, age 22±5 yr, body mass 69.8±11.2 kg) consumed 591.5 mL of water or a protein shake in a randomized, crossover study. Body composition was assessed via multi-frequency bioelectrical impedance (InBody 270) at baseline, immediately post-consumption (0 minutes), 30 minutes post-consumption, and 60 minutes post-consumption. Results: There were no significant changes in body mass, lean body mass, and fat mass between the water and protein groups over the treatment period. In both water and protein groups, percent body fat was significantly greater (p<0.0001) at time points 0, 30, and 60 minutes compared to baseline. Conclusions: The acute consumption of either water or an isovolumic protein shake resulted in a measurable increase in percent body fat immediately post-consumption as well as 30 and 60 minutes thereafter.