Genetic and Biochemical Characteristics of Medically-Complicated Obesity and Response to Bariatric Surgery

Study participation by invitation after complete pre-surgical work up at UC Davis Health System. Patients will be invited to participate if they meet all inclusion criteria's after completing all necessary clinical visits including lab studies, counseling, and participation in educational programs. During the pre-operative visit patients interested in participation will complete all necessary consent documentation. Pre-operative labs (blood and urine) will be collected along with additional blood, urine, and fecal samples will be collected pre-operatively. During surgery (Roux-en-Y Gastric Bypass surgeries only) tissue collection will include subcutaneous & omental fat, jejunum, and liver biopsy. Post surgery patient will be observed for weight loss and resolution of co-morbidities. At designated times post surgery when lab studies are ordered additional blood/urine samples will be collected and analyzed.