This study will assess effects of an acute dose of the amino acid arginine on metabolism in healthy young men.

A double - blind randomized, crossover design trial examining arginine vs. placebo beverage treatments will be performed. The primary objective is to determine the effects of arginine assessed by standard laboratory assays and metabolomics. To accomplish the objective standardized meals will be provided for 2 days preceding treatment for dietary consistency. Participants will arrive at the center following a 10-12 hr fast. Blood samples will be collected at baseline (fasting), 1.5 hrs, 3.0 hrs, 6.0 hrs, and 24 hrs post treatment. Plasma prolactin, growth hormone, amino acids, glucose, insulin, triacylglycerols, thyroid hormones (TSH, T3, and T4), sex hormone binding globulin (SHBH), testosterone, cortisol, DHEA, and citrulline will be measured. Metabolomics will be measured at 3 time points for each treatment. Peripheral arterial tonometry (PAT) will also be performed at ~2 hrs following treatment to examine endothelial function in response to nitrous oxide release. In addition, psychological status including fatigue will be assessed using a standardized mood questionnaire (POMS).

Inclusion Criteria:

• BMI 18.5 - 25 kg/m2.
• Must be physically active (exercise at least 2 days/week).
• Willing to refrain from alcohol and supplements for the duration of the study.
• Willing to refrain from supplement ingestion, nuts, watermelon, and cracklins (fatback) for the 2 weeks prior to the initial treatment diet through the duration of the study.

Exclusion Criteria:

• HIV or AIDS
• Uncontrolled CVD/arrhythmia
• Type I or type II diabetes
• Pregnancy (or breastfeeding)
• Diagnosed eating disorder
• Non-normal sleeping patterns
• Chronic neurological condition
• Altered metabolism including growth hormone disorders
• Use of nicotine or tobacco products
• Heavy caffeine use (≥ 350 mg caffeine/d)
• Whole blood donation within previous eight weeks
• Protein supplementation
• Protein wasting disease.
• Exclusionary medications include diuretics, beta-blockers, weight loss medications or diet pills, anti-inflammatory drugs (corticosteroid/ anabolic steroid/NSAID), antipsychotic medication or other medication that may affect fluid balance, metabolism, or body weight.
• Prisoners and adults who are unable to consent will be excluded from the study.
• Lastly any other medical, psychiatric, or behavioral factors in the judgement of the Principle Investigator that may interfere with study participation or the ability to follow the protocol.