Metformin's Effect on Glucagon-induced Glucose Production and Protein Metabolism.

Inclusion Criteria: * 35-65 years of age * Fasting blood glucose \>100 mg/dl * BMI 27-36 kg/m2 * Waist Circumference: Men ≥ 104 cm; women ≥ 88 cm * If previously on anti-diabetic medication, should be off for at least 1 month Exclusion Criteria: * Active use of hypoglycemic agents (\< 1 month) * Renal failure, creatinine ≥ 1.5 mg/dL in men or ≥ 1.4 mg/dL in women * Alanine aminotransferase levels exceed 135 IU/L or aspartate aminotransferase levels exceed 129 IU/L (3 x the upper limit of normal) * Congestive Heart Failure (EF \< 40 %) * Active coronary artery disease * Recent (less than 6 weeks) or planned imaging study requiring IV contrast * Participation in structured exercise (\> 2 hr per week) * Recent change in dietary habits or weight * Tobacco use * Use of systemic glucocorticoids * Anti-coagulant therapy (warfarin/heparin) * Pregnancy or breastfeeding * Alcohol consumption greater than 2 drinks/day * Uncontrolled Hypothyroidism, abnormal thyroid stimulating hormone levels * Metformin Allergy