<qa>  How many subjects will be evaluated in this study?This is a pilot study to collect the relevant information for planning a larger and more definitive investigation. A total of thirty subjects will be evaluated in this study to be conducted at the Boston Medical Center. The study population will consist of obese patients who meet the criteria and have been scheduled by their surgeon for GBS. We plan to enroll a total of 30 subjects scheduled for GBS. Patients will be assigned according to standard surgical care to either open or laparoscopic surgery. We plan to enroll 20 subjects who undergo laparoscopic GBS LAP and 10 subjects who undergo open GBS OPEN. All potential subjects will have undergone baseline screening as a part of their routine medical evaluation performed by Dr. Apovian or Dr. McDonnell in the Nutrition Center at BMC. This standard testing includes medical history, physical examination, complete blood count, serum electrolytes, BUN, creatinine, fasting blood glucose and glycosylated hemoglobin. If patients are identified as having type 2 diabetes or glucose intolerance, they will be provided informed consent. If consented subjects meet all the inclusion and exclusion criteria, each will undergo a baseline oral glucose tolerance test OGTT approximately one week before surgery. Plasma concentrations of insulin, GIP, glucagon, and GLP-1 will also be measured along with glucose levels and other peptides CCK, ghrelin, c-peptide at the same intervals, using commercially available assay kits. Post-operatively, subjects in the LAP group will undergo 2 OGTTs, while subjects in the OPEN group will undergo 2 OGTTs and one glucose tolerance test through the gastrostomy tube GGTT. The results of the postoperative OGTTs will be compared with baseline OGTTs. In a separate analysis, the results of the GGTTs will be compared with the baseline and postoperative OGTTs. 