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.

Inclusion Criteria:

• Body mass index < 30.0 kg/m2
• Weight stable in the past 2 months (± 2.27 kg)
• Healthy without evidence of chronic illness or musculoskeletal injury as determined by the USARIEM Office of Medical Support and Oversight (OMSO) or home duty station medical support
• Functional exercise (i.e., step ups, box jumps, body mass movements) and/or aerobic exercise trained defined by self-report as performing ≥ 2 sessions/wk for previous 6 months
• Willing to refrain from taking any nonsteroidal anti-inflammatory drugs (e.g., aspirin, Advil®, Aleve®, Naprosyn®), or any other aspirin-containing product for 10 days before the first ~8.5 hour laboratory day and at least 5 days after completing the last ~8.5 hour laboratory day
• Willing to refrain from alcohol, smoking any nicotine product (includes e-cigarettes), vaping, chewing tobacco, caffeine, and dietary supplements after the completing the baseline period until the end of the study
• Must obtain supervisor approval for federal civilian employees and non-HRV active duty military personnel working within the US Army Natick Soldier Systems Center
• Females must have normal menstrual cycles between 26-32 days in duration; 5 menstrual cycles within the past 6 months; or able to provide documentation of oral/hormonal contraceptive use which contains low-dose estrogen/progesterone to maintain continuous levels throughout the 28-day cycle (i.e., no placebos)

Exclusion Criteria:

• Metabolic or cardiovascular abnormalities, gastrointestinal disorders (e.g., kidney disease, diabetes, cardiovascular disease, etc.)
• Abnormal PT/PTT test or problems with blood clotting
• History of complications with lidocaine
• Present condition of alcoholism, anabolic steroids, or other substance abuse issues as assessed by OMSO
• Participation in blood donation within 8-wk of beginning the study
• Pregnant, trying to become pregnant, and/or breastfeeding (results of urine pregnancy test or self-report for breastfeeding will be obtained before body composition testing)
• Unwillingness or inability to consume study diets or foods provided due to personal preference, dietary restrictions, and/or food allergies
• Unwillingness to adhere to study physical restrictions

double (participant and investigator)