Duodenal switch surgery uses a malabsorptive and a restrictive approach to weight loss surgery. In this surgery, the quantity of food that the stomach can hold is reduced and the amount of calories absorbed is reduced. This is achieved when the surgeon combines the moderately sized stomach pouch with bypassing part of the small intestine, allowing the patient to lose weight without significantly altering eating habits. It is important to note, however, that after surgery, the stomach can only hold one half to one full ounce of food.
The stomach remains attached the first segment of the small intestine, the duodenum, which is then separated from the rest of the small intestine. The duodenum is then attached to the lowest part of the small intestine, bypassing the majority of the second and third segments of the small intestine.
Patients having this surgery can lose up to 70 to 80% of his excess weight in the two years that follow the procedure. However, patients who choose this type of surgery are at much higher risk for nutritional deficiencies than with other types of weight loss surgery. Nutritional supplements, including vitamins and minerals, will be necessary for the lifetime of the patient.