Distal Proximal Roux gastric bypass with very little malabsorbtion of calories and nutrients. Medial Roux gastric bypass with moderate malabsorbtion of calories and nutrients. Distal Roux gastric bypass with significant malabsorbtion of calories and nutrients. Duodenal Switch/Biliopancreatic Diversion A special Roux gastric bypass with significant malabsorbtion of calories and nutrients. Enables patient to eat larger portions.