Effects of Acipimox on Mitochondrial Function in Obesity

Inclusion Criteria: 1. Men and women age 18-55 years old 2. Body Mass Index (BMI) ≥ 30 kg/m2 3. Waist circumference ≥ 102 cm in men and ≥ 88 cm in women 4. Hypertriglyceridemia defined as triglycerides ≥ 150 mg/dl OR Insulin resistance defined as elevated fasting glucose (≥ 100 mg/dl but \<125 mg/dl) or hyperinsulinemia defined as fasting serum insulin ≥ 10 uU/ml. Exclusion Criteria: 1. Subjects on any hormonal treatment including estrogen, hormone replacement therapy, oral contraceptives, testosterone, glucocorticoids, anabolic steroids, GH, GH releasing hormone or Insulin like growth factor (IGF)-1 within 3months of enrollment. 2. Subjects who have a known history of diabetes, using any anti-diabetic drugs, or fasting blood glucose of ≥ 125 mg/dl. 3. Use of cholesterol lowering medication including niacin or fish oil. 4. Changes in anti-hypertensive regimen within 3months of screening. 5. Chronic illness including HIV, anemia (Hgb \<12 g/dL), chronic kidney disease (Creatinine \> 2 mg/dL), or liver disease (SGOT \> 2.5 x upper limit normal). 6. Use of Aspirin, Clopidogrel (Plavix), Warfarin (Coumadin) or other anti-coagulants 7. History of or active peptic ulcer disease 8. History of any recent cardiovascular event including myocardial infarction (MI; heart attack), cerebral vascular accident (CVA; or stroke) or transient ischemic attack (TIA; or mini-stroke) within 3 months of screening visit, unstable angina pectoris, oxygen-dependent severe pulmonary disease 9. Subjects with contraindication for an MRI study including any significant metal in their body including surgical clippings, or pacemakers and known claustrophobia. 10. History of recent alcohol or substance abuse (\< 1 year) 11. Positive pregnancy test or lactating females 12. Women of child-bearing potential not currently using non-hormonal birth control methods including barrier methods (intra-uterine device or IUD, condoms, diaphragms) or abstinence 13. Subject is currently enrolled in another investigational device or drug trial(s), or subject has received other investigational agent(s) within 28 days of baseline visit.