Surgery leads to weigh loss in pathological obesity, but it is uncertain which surgical procedure is the most effective and safest for this condition. The option of surgery for pathological obesity is considered when all the other treatments have failed.

The bariatric procedures to reduce weight share 2 characteristics: intestinal malabsorption and gastric restriction. The procedures based on malabsorption involve the re-routing of the small intestine to reduce its functional length or the efficiency of the mucous membrane for the absorption of nutrients.

The jejunoileal bypass is not performed anymore as it is associated with liver failure, cirrhosis, renal lithiasis by oxalate, enteritis, arthritis and metabolic deficiency.

The derivation of the bilio - pancreatic secretion toward the distal 50 cm of the ileum added to the distal gastrectomy can be associated with caloric-protean malnutrition, bone disease and the deficit of liposoluble vitamins, calcium, iron and vitamin B12.
 
The restrictive procedures consist in the formation of a small gastric pouch to reduce the capacity of food consumption and include the gastroplasty, gastric banding and the gastric bypass.

Many surgeons have abandoned the gastroplasty because the results of randomized studies showed a smaller weight loss in comparison with the gastric bypass in Roux Y.

The adjustable gastric banding procedure can be performed by laparoscopy. Nevertheless, it is associated with collateral symptoms such as queasiness, vomiting, pyrosis, abdominal pain, the sliding of the band, or insufficient weight loss.

The Gastric bypass is the surgical procedure of choice since it produces greater weight loss that is also maintained longer-term.