Bariatric surgery procedures induce weight loss through restriction and/or malabsorption. The mechanisms underlying type 2 diabetes remission and others metabolic improvements after Roux-en-Y Gastric Bypass (RYGB), sleeve gastrectomy (SG) or biliopancreatic diversion with duodenal switch (BPD-DS) have not yet been formally studied. The investigators propose a longitudinal study with the overall objective of measuring the long-term impact of these three bariatric surgeries (RYGB, SG, BPD-DS) on metabolic, renal and cardiovascular fate in patients with type 2 diabetes. The investigators overall hypothesis is that some bariatric procedures generate hitherto unrecognized effects on many disease-related outcomes, which greatly contributes to their beneficial impact in diabetic patients. The investigators propose 3 specific aims: 1) to establish the long term effect of the three surgeries on the metabolic recovery and quality of life in groups of diabetic patients treated with insulin, hypoglycemic agents or diet; 2) to establish the long term impact of the three surgeries on renal and cardiovascular functions in subgroup of patients with these conditions; 3) to compare metabolic impact of surgeries to those of best medical care for diabetes in a non-surgical control group. For most severely obese patients, lifestyle interventions, perhaps effective in inducing short-lived weight losses, are ineffective for long-term weight loss maintenance and durable metabolic recovery. The increasing popularity of obesity surgeries calls for a better understanding of the underlying mechanisms. This is especially true and urgent when considering that knowledge on the relative impact of each procedure (i.e. SG vs. RYGB and BPD-DS) in resolving T2D is still limited. Better knowledge on each of the procedures will allow stronger scientific rationale for selecting the right surgery for the right patient and improve care for the severely obese individual.

Inclusion Criteria:

• BMI ≥ 35
• type 2 diabetes
• HbA1c ≥ 6,5 % or fasting glycemia ≥7mmol/l or non-fasting glycemia ≥11mmol/l
• able to consent

Exclusion Criteria:

• pregnancy
• past esophageal, gastric or bariatric surgery
• irritable bowel, unexplained intermittent vomiting, severe abdominal pain, chronic diarrhea or constipation
• history of gastric or duodenal ulcers
• pre-operatory hypoalbuminemy
• history of renal, hepatic, cardiac or pulmonary severe disease
• taken of corticosteroid in the last month
• evidence of psycological problem that may affect the capacity to understand the project and to comply with the medical recommandations
• history of drug use or alcool abuse in the last 12 months
• history of gastro-intestinal inflammatory diseases