Metabolomic Analysis of Hepatic Insulin Resistance

Inclusion Criteria: Subjects eligible to participate in the study will be: 1. Adults over age 18; 2. Patients enrolled in the bariatric surgery clinic who are planning to undergo and have insurance approval for bariatric surgery; 3. Insulin sensitive (based on HOMA-IR calculated from screening labs) OR insulin resistant (based on HOMA-IR and or personal history of diet controlled diabetes) 4. Able and willing to give informed consent. Exclusion Criteria The following will exclude subjects from study participation: 1. Clinically significant medical issues outside of diabetes (eg, pregnancy, cardiovascular disease, uncontrolled pulmonary disease). If female and of child bearing potential, a pregnancy test will be performed and confirmed negative prior to participation in the study and prior to the scheduled glucose clamp procedure. 2. A history of hematologic (platelets \<100 x107/L), hepatic (liver function tests \[LFTs\] \>2X upper limit of normal), renal (Creatinine \>1.5 mg/dL), pulmonary/ cardiac abnormalities (ie, abnormal electrocardiogram \[EKG\]). 3. Use of anti-diabetes medication, anticoagulants, or medication that might alter lipids. If the subject has a history of diabetes, it should be controlled by diet alone. 4. Inflammatory or celiac intestinal disease; 5. Untreated thyroid disease; 6. Excessive alcohol use, illicit drug use, or active untreated psychiatric disease.