A bariatric surgical treatment for obesity in which most of the stomach is removed. The small pouch that remains is connected to a small segment of the duodenum, which is linked directly to the cecum, bypassing the rest of the small intestine. The procedure restricts the intake of nutrients and causes malabsorption, both of which lead to weight loss. Successful procedures result in sustained weight loss of about 25% of body weight, a result as good as any other surgical treatment for overweight. Common complications of the procedure include iron-deficiency anemia, deficiencies in the absorption of vitamins A, D, E, and K and the minerals calcium and magnesium, gradual bone loss, foul smelling stools, and failure of surgical anastomoses. The operation takes more time to perform than other bariatric surgeries and tends to have more immediate postoperative complications.