Weight loss in the first year or two after gastric bypass surgery is usually significant. The average is about 70% of excess weight, and the long-term average weight loss is 50% of the excess weight. This figure has been stable for 20 years. A recent study published in The New England Journal of Medicine examined the 10-year weight change in a large clinical cohort of veterans who underwent Roux Y-gastric bypass (RYGB) compared to non-surgical patients. The results showed that RYGB induced significantly greater weight loss among veterans than sleeve gastrectomy (SG) or adjustable gastric banding (AGB) at 4 years.
All of the patients underwent a Roux-en-Y gastric bypass, in which surgeons closed all but one of the stomach's pockets and then omitted part of the small intestine. In addition, Carlsson and colleagues analyzed the mortality data of 2,007 obese adults who underwent banding surgery, gastroplasty with vertical bands, or gastric bypass (average age: 47.2 years; 29.2% men) and of 2,040 adults who received standard care for obesity and served as a control group (average age, 48.7 years; 29.1% men).The findings showed that patients undergoing RYGB lost 21% more of their initial weight than compatible non-surgical patients at 10 years. Furthermore, RYGB induced significantly greater weight loss than sleeve gastrectomy or adjustable gastric banding at 4 years. While the use of gastric bypass is increasing rapidly, the possible benefits of the procedure for life expectancy are unknown. Compared to other major surgical procedures, gastric bypass for morbid obesity is associated with a substantial increase in life expectancy.