This study aims to understand the biological processes that link obesity to diseases including insulin resistance and diabetes. Our approach involves studying the health of patient undergoing weight loss either via weight reduction surgery or by medically supervised liquid formula diets. Patients must be enrolled in a weight treatment program at Emory Bariatrics, Emory University, Atlanta GA, to be eligible for this study. This study does not cover the cost of treatment at Emory Bariatrics. The hypothesis is that decreases in adipose-tissue derived factors during weight loss will be related to improvement in insulin function.