The main objective is to prospectively evaluate long-term efficiency of bariatric surgery in terms of weight loss. Moreover, this cohort wants to assess the long-term effectiveness of bariatric surgery on comorbidities and quality of life, the medical and economic impact of bariatric surgery (before-after comparison using data from health insurance), estimates the incidence of mortality and morbidity of bariatric surgery and to finish describe the evolution of patients in case of new-surgery. From a methodological point of view, the Obesity cohort is a prospective cohort study, single-center, open, with aftercare performed during life of patients. The number of inclusions is to 1500 patients. After surgery , patients will be followed at least 4 visits the first year and at least 2 visits a year then. The recommendations of the french health ministry (HAS), the frequency of visits may be increased according to the patient's progress. Follow-up visits of patients after bariatric surgery will be performed by physicians or surgeons of the multidisciplinary team responsible for the care of the patient (digestive and reconstructive surgery, anesthesiology, endocrinology, medical imaging, gastroenterology, immunology and physiology) . It will be insured for life, obesity is a chronic disease and because of the risk of late complications.