The operation is prescribed to treat severe obesity (defined as a body mass index greater than 40), type 2 diabetes, hypertension, obstructive sleep apnea, and other comorbid conditions.

[press release 1] A meta-analysis of 174,772 participants published in The Lancet in 2021 found that bariatric surgery was associated with 59% and 30% reduction in all-cause mortality among obese adults with or without type 2 diabetes respectively.

In 1991, the National Institutes of Health (NIH) sponsored a consensus panel whose recommendations have set the current[update] standard for consideration of surgical treatment, the body mass index (BMI).

[web 1] The Consensus Panel of the National Institutes of Health (NIH) recommended the following criteria for consideration of bariatric surgery, including gastric bypass procedures: The Consensus Panel also emphasized the necessity of multidisciplinary care of the bariatric surgical patient by a team of physicians and therapists to manage associated comorbidities and nutrition, physical activity, behavior, and psychological needs.

This conference, composed of physicians and scientists of both surgical and non-surgical disciplines, reached several conclusions, including: In recent comparisons with sleeve gastrectomy, gastric bypass has shown slightly better outcomes in diabetes remission and weight maintenance.

According to a 2021 evidence update, Roux-en-Y gastric bypass (RYGB) patients were more likely to maintain weight loss over five years, with a reduced relapse rate in Type 2 diabetes.

[journal 4] Laparoscopic surgery is performed using several small incisions, or ports: one to insert a surgical telescope connected to a video camera, and others to permit access to specialized operating instruments.

The use of this method has greatly popularized the operation due to associated benefits such as a shortened hospital stay, reduced discomfort, shorter recovery time, less scarring, and minimal risk of incisional hernia.

The patient will experience a very rapid onset of the stomach feeling full, followed by a growing satiety (or "indifference" to food) shortly after the start of a meal.

As the Y-connection is moved further down the gastrointestinal tract, the amount available to fully absorb nutrients is progressively reduced, traded for greater effectiveness of the operation.

The MGB has been suggested as an alternative to the Roux-en-Y procedure due to the simplicity of its construction and is becoming more and more popular because of low risk of complications and good sustained weight loss.

This prevents the partially digested food from entering the first and initial part of the secondary stage of the small intestine, mimicking the effects of the biliopancreatic portion of Roux-en-Y gastric bypass (RYGB) surgery.

Most people do not stop eating simply in response to a feeling of fullness, but the patient rapidly learns that subsequent bites must be eaten very slowly and carefully, to avoid increasing discomfort or vomiting.

Changes in circulating hormone levels after gastric bypass have been hypothesized to produce reductions in food intake and body weight in obese patients.

However, these findings remain controversial, and the exact mechanisms by which gastric bypass surgery reduces food intake and body weight have yet to be elucidated.

[web 3] Mortality and complications are affected by pre-existing risk factors such as degree of obesity, heart disease, obstructive sleep apnea, diabetes mellitus, and history of prior pulmonary embolism.

Due to insufflation of the abdominal cavity with CO2 for the surgery, the venous return is diminished and this will lead to deep vein thrombosis of the lower extremities.

Antecolic antegastric Roux-en-Y gastric bypass surgery has been estimated to result in internal hernia in 0.2% of cases, mainly through Petersen's defect.

[journal 8] An incisional hernia occurs when a surgical incision does not heal well; the muscles of the abdomen separate and allow protrusion of a sac-like membrane, which may contain bowel or other abdominal contents, and which can be painful and unsightly.

If that seal fails to form for any reason, fluid from within the gastrointestinal tract can leak into the sterile abdominal cavity and give rise to infection and abscess formation.

[journal 9] Possible causes of such ulcers are: This condition can be treated with: Normally, the pyloric valve at the lower end of the stomach regulates the release of food into the bowel.

When the gastric bypass patient eats a sugary food, the sugar passes rapidly into the intestine, where it gives rise to a physiological reaction called dumping syndrome.

They include:[journal 10] After surgery, patients feel fullness after ingesting only a small volume of food, followed soon thereafter by a sense of satiety and loss of appetite.

Recurring nausea and vomiting eventually change the absorbance rate of food, contributing to the vitamin and nutrition deficiencies common in post-operative gastric bypass patients.

[journal 15] There have been reported cases in which pica recurs after gastric bypass in patients with a pre-operative history of the disorder, which is possibly due to iron deficiency.

[journal 2] A meta-analysis of 174772 participants published in The Lancet in 2021 found that bariatric surgery was associated with 59% and 30% reduction in all-cause mortality among obese adults with or without type 2 diabetes respectively.

[citation needed] The patient's out-of-pocket cost for Roux-en-Y gastric bypass surgery varies widely depending on the method of payment, region, surgical practice, and hospital in which the procedure is performed.

Energy levels in the period following the surgery can be low, both due to the restriction of food intake and negative changes in emotional state.

Muscle weakness may result in balance problems, difficulty climbing stairs or lifting heavy objects, and increased fatigue following simple physical tasks.

These extra surgeries have inherent risks but are even more dangerous when coupled with the typical nutritional deficiencies that accompany convalescing gastric bypass patients.