The purpose of this research study is to examine whether specific genes (e.g. SLC16A11) affect how human beings respond to food and a medication that is commonly used to treat type 2 diabetes. The food the investigators will be studying is specially prepared to contain protein, carbohydrate, and fat. The drug the investigators are studying is metformin. The investigators hypothesize that physiological responses to the meal and to the medication will differ between carriers and non-carriers of genes associated with type 2 diabetes.

Inclusion Criteria:

• Adult males or non-pregnant females
• Age 18-79
• Able and willing to give consent relevant to genetic investigation

Exclusion Criteria:

• Women who are pregnant, nursing, or at risk of becoming pregnant
• Currently taking any medications used for the treatment of diabetes
• History of liver disease and/or aspartate aminotransferase (AST) or alanine aminotransferase (ALT) more than 3 times upper limit of normal (ULN)
• Estimated glomerular filtration rate (eGFR) < 60 ml/min/1.73 m2 as calculated by the Modification of Diet in Renal Disease equation
• Currently taking or intending to take during the study duration any medication known to affect glycemic parameters, such as glucocorticoids, growth hormone, or fluoroquinolones
• Contraindications to safe use of metformin, including planned radiologic or angiographic study requiring contrast within one week of the study completion
• Planned changes to any prescribed medications, specifically diuretics, during study enrollment
• Participation in any other interventional study during the study duration
• Conditions causing intestinal malabsorption, including celiac disease or a history of intestinal or gastric bypass surgery
• Dietary restrictions that would prevent consumption of a MMTT
• Objection or inability to take metformin