The duodenal-jejunal surgery is a type of combined malabsorptive and restrictive weight loss surgery. The duodenal-jejunal is known by multiple names, including DS and biliopancreatic diversion with duodenal switch. This surgery decreases both the quantity of food that can be accommodated by the stomach and the number of calories that can be absorbed and used by the body.

The duodenal switch (DS) procedure, also known as biliopancreatic diversion with duodenal switch (BPD-DS) or gastric reduction duodenal switch (GRDS), is a weight loss surgery procedure that is composed of a restrictive and a malabsorptive aspect.The duodenal switch combines the creation of a moderately sized stomach pouch with bypassing part of the small intestine. This allows the patient to lose weight without significantly altering their eating habits. The stomach is able to hold approximately five to six ounces of food, while other common procedures typically leave it able to hold one half to one full ounce.