Inclusion Criteria:

• * BMI 40 - 50 kg/m2.
• * Mo active physical illness that would interfere with mobility or weight loss after bariatric surgery

Exclusion Criteria:

• * Type 1 or Type 2 Diabetes diagnosis or fasting plasma glucose ≥126 mg/dL
• * Active coronary artery disease
• * Participation in structured exercise (\>2 times per week for 30 minutes or longer)
• * Smoking
• * Medications known to affect adipose tissue metabolism (e.g., beta blockers, corticosteroids)
• * Renal insufficiency (serum creatinine \> 1.5mg/dl)
• * Chronic active liver disease (Bilirubin \> 17mmol/L, AST \> 144 IU/L, or ALT\>165IU/L)
• * Pregnancy or breastfeeding.