Gastric bypass is a type of weight loss or bariatric surgery performed in the United States to help obese or morbidly obese patients who struggle to lose weight with non-surgical methods. There are other bariatric surgeries, like adjustable gastric banding, sleeve gastrectomy or biliopancreatric diversion with duodenal switch, but gastric bypass is the most common and it is considered the gold standard of bariatric surgery. It helps patients by both reducing the size of the stomach and redirecting the digestive system.

During the procedure, patients go under general anesthesia, with the surgeon beginning by dividing the stomach and stapling it in order to create a small pouch about the size of a walnut. Due to the reduction of the organ, patients feel full faster even after eating smaller amounts of food. The second part of the surgery is the bypass itself, which results from the connection of the pouch to the part of the small intestine called jejunum. Since the food bypasses part of the stomach and the small intestine, the body absorbs fewer calories. The combination of the two parts facilitate weight loss when combined with a healthy diet and regular exercise.

Data on Gastric Bypass Safety

According to the study “How Safe is Bariatric Surgery?,” conducted by Jacob A. Greenberg and Malcolm K. Robinson, gastric bypass is a safe procedure that provokes weight loss through the restriction of food intake, as well as through a variety of poorly understood neurohormonal changes that enhance satiety. The investigators also found that the 30-day composite end point of death, major thrombotic complication, reintervention and prolonged hospitalization was 4.8% for laparoscopic Roux-en-Y gastric bypass surgery, and 7.8% for open Roux-en-Y gastric bypass surgery.

However, there is the possibility of complications, including anastomotic leaks, pulmonary embolism, pneumonia allergy to the medication used in the anesthesia, blood clots, infection, and lung or breathing problems, which are related to the surgery itself, as well as bowel obstruction, dumping syndrome, nausea or vomiting, gallstones or hernias, low blood sugar, malnutrition, vitamin deficiencies, stomach perforation, ulcers, vomiting, and staple-line failure in the pouch. Short-term risks occur in about 10% of the cases, long-term occurrences happen in 15.3%, while death is particularly rare but can also occur. 

Gastric Bypass Efficacy Studies

“Outcomes of bariatric surgery are getting better all the time, as surgeons gain experience in performing these technically demanding procedures laparoscopically. The risks are not trivial, but they are acceptably low. The benefits: not only do patients lose weight and keep it off, now there are convincing data that many patients are cured of obesity-related diseases, notably type 2 diabetes. In fact, the procedure may pay for itself within a few years by reducing medical costs due to obesity-related illness. Best of all, the long-term mortality rate seems to be lower for morbidly obese patients who undergo this surgery than for those who do not,” as explained in the study “Risks and benefits of bariatric surgery: Current evidence” about gastric bypass procedures.

Gastric bypass produces significant long-term weight loss of about 60 to 80 percent excess weight loss, with a typical maintenance higher than 50%, which is superior to the adjustable gastric banding, but inferior to the sleeve gastrectomy and the biliopancreatic diversion with duodenal switch, according to the American Society for Metabolic and Bariatric Surgery (ASMBS). In addition, it also helps patients improve energy expenditure, comorbidities, overall health and quality of life, and regain their confidence.

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