Bilio-Pancreatic diversion with Duodenal Switch (BPD-DS) is the most effective bariatric procedure in terms of long-term weight loss and remission rate of Type 2 Diabetes. However, its technical difficulty and increased risk of long-term nutritional deficiencies have been a major hindrance to its diffusion.

Recently, a " simplified " technique of Duodenal-Switch has been proposed by Sanchez-Pernaute et al. This technique involves the creation of a Sleeve Gastrectomy, transection of the first duodenum, and connection of the duodenum to an omega-loop of small bowel instead of a terminal intestinal loop used in standard BPD-DS.

The overall objective of this study is to assess in a prospective randomized blinded trial, the outcomes of this new procedure, using a comprehensive clinical evaluation and follow-up method. This could potentially change the clinical practice and surgical approach in our Institution.

Bilio-Pancreatic diversion with Duodenal Switch (BPD-DS) is the most effective bariatric procedure in terms of long-term weight loss and remission rate of Type 2 Diabetes. However, its technical difficulty and increased risk of long-term nutritional deficiencies have been a major hindrance to its diffusion. Our team, with more than 4000 BPD-DS performed since the early 1990's, is recognized internationally for its expertise with this specific procedure.

Recently, a " simplified " technique of Duodenal-Switch has been proposed by Sanchez-Pernaute et al. This technique involves the creation of a Sleeve Gastrectomy, transection of the first duodenum, and connection of the duodenum to an omega-loop of small bowel instead of a terminal intestinal loop used in standard BPD-DS.

This new procedure, called Single Anastomosis Duodenal Switch has the potential benefit of decreasing the complexity of the standard BPD-DS by avoiding one of the two intestinal anastomoses usually needed. This could potentially decrease the rate of peri-operative complications and increase access to this type of surgery.

However, the length of the common channel (250cm) is more than doubled compared to standard BPD-DS, which could also change significantly the outcomes of the procedure itself. Indeed, the length of the common channel conditions the absorption of fat and fat-soluble vitamins.

Currently, the scientific literature regarding this procedure is scarce, with only one author who published his 2-years outcomes, in a cohort study of 100 patients. In addition, this report presents major limitations. In example, the length of the omega loop was increased from 200 to 250cm during the course of the study, in order to decrease the rate of protein deficiency and reoperation for malnutrition. This and other limitations make it hard to assess the actual results of the technique.

The overall objective of this study is to assess in a stronger study design (i.e. a prospective randomized single blinded trial), the outcomes of this new procedure, using a comprehensive clinical evaluation and follow-up method. This could potentially change the clinical practice and surgical approach in our Institution.

Inclusion Criteria:

• Age ≥18 years and ≤60 years
• Fulfill criteria for bariatric surgery as coined by National Institutes of Health BMI≥35
• Give written informed consent

Exclusion Criteria:

Participants who meet any of the following criteria at the time of the baseline visit are excluded from the study:

• Presence of the following baseline comorbidities:
• Inflammatory bowel disease (IBD),
• Cirrhosis
• History of gastric or duodenal ulcers
• Preoperative hypoalbuminemia (<35 g/L)
• History of severe renal, hepatic, cardiac or pulmonary disease
• Past esophageal, gastric or bariatric surgery
• Type 1 Diabetes
• Pregnancy
• Evidence of psychological problem that may affect the capacity to understand the project and to comply with the medical recommendations
• History of drug use or alcohol abuse in the last 6 months
• History of gastro-intestinal inflammatory diseases