This study try to identify differences in length of operation, weight loss and complications, between two different bariatric surgical techniques, the laparoscopic Roux-en-Y gastric bypass and the laparoscopic Roux-en-Y banded gastric bypass. The study will be conducted in a Spanish public health system hospital. The patients of the trial will have the preoperative studies, hospital treatment during the admission, postoperative treatment and follow up as any other patient included in the hospital bariatric surgery program. The study cases will have placed around the gastric pouch a band of polypropylene mesh, and will be randomly choose between the participants.