Fig. 1.

Bariatric Procedures. A. Roux-en-Y bypass involves creation of a small gastric pouch from the newly isolated stomach and proximal small bowel that is excluded from gastric transfer. The pouch is anastomosed to the small intestine, forming the Roux limb. Food enters the pouch, moves through Roux limb and then reaches the common channel where pancreatic fluids and bile have entered from the bypassed bilipancreatic limb. B, C. Banding and gastric sleeve are purely restrictive procedures with bowel beyond the stomach remaining intact. D. BPD/DS involves creation of a gastric sleeve along with and resection of the majority of duodenum beyond the most proximal portion to the stomach. The distal segment of small intestine is then connected to the stomach and the bypassed duodenal portion (biliopancreatic limb) anastomosed to the last portion of the small intestine, forming a common channel, often shorter and resulting in greater malabsorption than that with Roux-en-Y. From Roust LR & DiBaise JK. Nutrient deficiencies prior to bariatric surgery. Curr Opin Clin Nutr Metab Care. 2017 Mar;20(2):138–144; used with permission of Mayo Foundation for Medical Education and Research, all rights reserved.