Effects of Essential Amino Acid-enriched Whey and Carbohydrate Co-ingestion on Protein Kinetics

Overview

Previous work conducted by the Investigators demonstrates that an essential amino acid(EAA)-enriched whey protein combination format is an efficient EAA/protein format to support enhanced whole-body protein balance and sustain muscle protein synthesis compared to isonitrogenous amounts of whey alone or a mixed-macronutrient meal. However, additional work is needed to optimize the formulation to ensure the best possible muscle and whole-body anabolic responses are achieved. This includes addressing the potential value of adding non-EAA/protein components to support energy demands. Providing additional non-protein energy to an EAA-enriched whey protein formulation may reduce the proportion of exogenous amino acids directed towards energy production thereby preserving its use for muscle protein synthesis. However, whether suppressing exogenous amino acid oxidation by providing additional carbohydrate allows for a greater muscle protein synthetic stimulus during moderate energy deficit (- 30% total energy requirements) is unknown. Therefore, this study will test the effects of EAA-enriched whey protein plus carbohydrate versus EAA-enriched whey plus additional EAA using a randomized, cross-sectional longitudinal study design.

In this study the Investigators will test the effects of EAA-enriched whey protein plus carbohydrate versus EAA-enriched whey plus additional EAA using a randomized, cross-sectional longitudinal study design. Thirty healthy, functional and aerobic exercise trained adults will complete two, 5-d controlled feeding phases, one maintaining energy balance and one inducing energy deficit in random order and separated by at least a 7d washout period. The difference in post-exercise (whole-body exercise model) muscle protein synthesis and whole-body protein turnover between the study treatments will be determined the day after each 5-d controlled feeding phase. This design will test the following hypotheses: 1) The magnitude of post-exercise anabolic response to EAA-enriched whey protein plus carbohydrate are enhanced compared to EAA-enriched whey protein plus additional EAA during energy deficit; 2) Regardless of protein treatment, the magnitude of anabolic response will be reduced during energy deficit compared to energy balance.