During each study trial Subjects will arrive at the Substrate Metabolism Laboratory at 7:00AM and will rest quietly for approximately 30 min. After which, the study team will measure their resting blood pressure and their resting metabolic rate. An intravenous catheter (IV) will then be placed in a vein of the subject's hand or forearm for blood sampling. The research team will then collect a small sample of fat tissue in the subject's abdomen with a needle. Next, subjects will drink a sweet sugar solution for an Oral Glucose Tolerance Test (OGTT) and the research team will collect blood samples every 15 min for 3 hours. After this 3 hour test, the IV catheter will be removed and subjects will be provided breakfast and discharged.