Inclusion Criteria:  Men and women aged 18 - 39 years Weight stable (±5 lbs) for at least 2 months prior to the start of the study Body mass index (BMI) between 18.5-30 kg/m2 Recreationally active (minimum 2-4 days per week aerobic and/or resistance exercise) Refrain from taking any NSAIDS (i.e., aspirin, Advil®, Aleve®, Naprosyn®, or any aspirin-containing product for 10 days before and at least 5 days AFTER each muscle biopsy. (*Tylenol® or acetaminophen is ok to use if needed for discomfort) Refrain from the use of alcohol and nicotine while on study diets Supervisor approval for federal civilian employees working within the US Army Natick Soldier Systems Center  Exclusion Criteria:  Metabolic or cardiovascular abnormalities, gastrointestinal disorders (i.e., kidney disease, diabetes, cardiovascular disease, hypertension etc.) Personnel or family history of blood clots Disease or medication (i.e., diabetes medications, statins, corticosteroids, etc) that affects macronutrient utilization and/or the ability to participate in strenuous exercise Allergies or intolerance to foods (including but not limited to lactose intolerance/milk allergy), vegetarian practices, or medications (including, but not limited to, lidocaine or phenylalanine) to be utilized in the study History of inflammatory bowel disease History of seizures Anemia (HCT < 38) and Sickle Cell Anemia/Trait Abnormal PT/PTT test or problems with blood clotting Present condition of alcoholism, use of nutritional/sports supplements, anabolic steroids, or other substance abuse issues History of malignancy Use of oral contraceptives or hormone replacement therapy due to increased risk of clotting Musculoskeletal injuries that compromise the ability to exercise Blood donation within 8 weeks of beginning the study Are unwilling or unable to eat study diets and foods provided and/or follow exercise prescriptions Pregnancy, post-partum status, or breastfeeding