The investigators are conducting this research study to find out if eating low or high levels of specific amino acids changes the levels of these same amino acids in the blood. Amino acids are the building blocks of protein that are normally found in food. The amino acids the investigators are studying are called branched chain amino acids. The investigators will look at the levels (amount) of branched chain amino acids in blood before and after consumption of specially prepared meals. The investigators hypothesize that circulating branch chain amino acid (BCAA) levels will be lower following a low BCAA-content diet compared with a high BCAA-content diet.

Inclusion Criteria:

• Adult males
• Ages 20-40
• Healthy

Exclusion Criteria:

• Age less than 20 or greater than 40
• Female sex
• Use of medications and herbal or vitamin supplements during the study or less than one month prior to enrollment in the study
• Body mass index (BMI) less than 20 or greater than 25
• Changes of more than 5 pounds in weight (increase or decrease) during the month prior to enrollment in the study
• Participation in more than 300 minutes of exercise per week during the month prior to enrollment in the study or plans for changes in exercise level during the study
• Known diabetes or pre-diabetes (based on prior diagnoses; use of medications to lower glucose; or fasting blood glucose > 100mg/dL at screening)
• Untreated hypertension (defined as systolic blood pressure > 140mmHg and diastolic blood pressure > 90mmHg)
• Use of nicotine-containing products, including those inhaled, chewed, or patches during the study.
• Use of drugs of abuse.
• Conditions causing intestinal malabsorption, including celiac disease or a history of intestinal or gastric surgery
• Restrictions that prevent adherence to standardized meals or unwillingness to adhere to a pre-specified meal plan, including abstinence from alcohol and limitation to 1 caffeinated beverage per day
• Known anemia (men, hematocrit < 38%) based on prior testing