Inclusion Criteria:

• obesity (> 85th% for age,BMI > 30); HbA1c <6%; hemoglobin and/or hematocrit within 2 standard deviations of normal range, without high risk of bleeding, without donation of blood in the previous 2 months; without involvement in any study evaluating an investigational drug or device for the previous 2 months; normal clotting studies; if female using barrier or oral contraception and with a negative pregnancy test.

Exclusion Criteria:

• Pregnant or lactating women; Patients with abnormal liver function defined as elevation of bilirubin, alkaline phosphatase, ALT, AST, or GGTP more than 1.5 times the upper limit of normal; Patients with kidney disease (serum creatinine > 1.5 mg/dL) macroalbuminuria (1+ protein on a standard urine dip-stick, or > 300 mg urinary albumin/day); (patients with microalbuminuria will be enrolled); Patients with any significant diseases or conditions, including emotional or psychiatric disorders and substance abuse, including history of binge drinking, that, in the opinion of the investigator, are likely to alter the patient's ability to complete the study ; Patients with metabolic acidosis (abnormal anion gap); History of gastric ulcer, dyspepsia, or upper or lower GI bleed; History of allergy to aspirin, or bleeding diathesis or currently on oral anticoagulants including warfarin, heparin, aspirin or other NSAIDs; Patients with major vascular event within 6 months of screening for the study (e.g., MI, stroke, CABG, angioplasty, PV surgery); Patients with chronic heart disease, or a history of myocardial infarction or stroke. Symptomatic angina pectoris or cardiac insufficiency as defined by the NYHA; classification as Functional Class III or IV; Patients who smoke more than one pack of cigarettes daily; Patients taking treatment medications known to affect insulin sensitivity (e.g. diuretics, beta-blockers); Patients with inadequately controlled serum lipid levels (total cholesterol ≥ 275 mg/dL and fasting triglycerides ≥ 450 mg/dL); Patients with history of cancer within 5 years prior to screening for the study other than basal cell carcinoma; active alcohol or other substance abuse.