also biliopancreatic bypass
: a gastric bypass surgical procedure in the treatment of severe obesity that involves removing a large portion of the stomach to form a small pouch and dividing the upper part of the small intestine so that one limb diverts food from the stomach pouch around much of the duodenum and jejunum and the other limb carries bile and pancreatic digestive enzymes to a section in the ileum where the two limbs are rejoined near the ileocecal valve
Some doctors recommend the biliopancreatic diversion, an extensive gastric bypass in which parts of the stomach are removed, but only for people who are several hundred pounds overweight. — The Washington Post, 29 Feb. 2000
By keeping ingested food separate from bile and digestive enzymes, a biliopancreatic diversion significantly reduces the intestinal area available for food digestion and nutrient absorption. A biliopancreatic diversion is often performed with another procedure that retains the stomach's pyloric sphincter and allows food to enter the first portion of the duodenum before diversion to the ileal section.