Bariatric surgery as a means of weight loss has become increasingly popular over the last 10-15 years. In addition to promoting weight loss, bariatric surgery has become increasingly recognized for use in the management of diabetes. Recent studies have indicated that bariatric surgery can result in a marked improvement in insulin sensitivity before long term weight loss is attained. The goal of this project is to delineate the changes in the insulin responsiveness of subcutaneous adipocytes obtained by needle biopsy 2 weeks prior to surgery vs. 12 weeks after bariatric surgery, which could account for improvements in overall insulin sensitivity seen before any long-term sustained weight loss has occurred. The investigators will also examine gene expression in adipocytes (fat cells).