Prospective randomized clinical trial aiming to compare laparoscopic Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG) with primary outcome on excess weight loss, and secondary outcomes on nutritional status, glycolipid profile, quality of life and pain assessments.

No consensus is proposed by the Medical and Surgical societies to define and / or prioritize surgical procedures in obesity surgery. Indications are based on patient's age, sex, dietary habits, the importance of overweight and associated comorbidities and even if rarely admitted, based on knowledge of surgical teams and the cost of interventions. Given the decrease of gastric banding procedures, Roux-en-Y gastro-jejunal bypass is often considered the reference procedure.

The gastric bypass, developed in the 60s, is performed laparoscopically since the early 90s. It allows for a 60% to 70% excess weight loss with control over 75% of comorbidities. It is recommended to follow these patients long-term because late complications can occur. These patients require ongoing information and regular monitoring. They must also have a hyper-protein diet and a vitamin substitute long-term (multivitamins, vitamin B12, calcium ...).

The Sleeve gastrectomy (SG) arises as an alternative to RYGB. It was classically proposed to patients with a BMI greater than 60 and significant comorbidities since the procedure let to a significant weight reduction in patients for whom any other procedure was too difficult to perform. The quality of the weight loss achieved in these patients has led many teams to analyze the results of this intervention without conducting an additional procedure. It appears from the literature that even performed alone, SG presents many benefits.

To clarify the role of sleeve gastrectomy in the bariatric procedures range, the investigators propose to conduct a prospective randomized study to compare laparoscopic sleeve gastrectomy to Roux-en-Y gastric bypass.

Inclusion Criteria:

• BMI >40 and < 60 kg/m2
• No contraindication to any of the procedures
• No contraindication to general anesthesia
• No known addiction
• Patient able to provide informed consent

Exclusion Criteria:

• Contraindication to general anesthesia
• Known psychiatric pathology
• Pregnancy
• Previous major digestive surgery
• Immunosuppressive treatment including corticoids
• Coagulopathy (INR>1.5) or platelets < 50 000/µl
• Anemia (Hb<10g/dl)
• Severe comorbidity
• Malabsorptive disease or gastro-intestinal disease
• Myocardial infarction in previous year, angina, cardiac failure