It is not known how much improvement in insulin regulated lipolysis (the breakdown of triglycerides) occurs following substantial, sustained weight loss. Researchers will test the effects of inflammation and lipolysis regulation in people before and after bariatric surgery (sleeve gastrectomy) to answer these questions.

The purpose of this study is to determine whether the adipose inflammatory cell and cytokine content in Class III obesity is related to lipolysis insulin resistance and, if so, whether sustained, substantial weight loss one year following bariatric surgery reduces inflammation in parallel with improved insulin regulation of lipolysis

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.