Bariatric surgery

Bariatric surgery (also known as metabolic surgery or weight loss surgery) is a surgical procedure used to manage obesity and obesity-related conditions.^[1][2] Long term weight loss with bariatric surgery may be achieved through alteration of gut hormones, physical reduction of stomach size (stomach reduction surgery),^[3] reduction of nutrient absorption, or a combination of these.^[2][4] Standard of care procedures include Roux en-Y bypass, sleeve gastrectomy, and biliopancreatic diversion with duodenal switch, from which weight loss is largely achieved by altering gut hormone levels responsible for hunger and satiety, leading to a new hormonal weight set point.^[4]

In morbidly obese people, bariatric surgery is the most effective treatment for weight loss and reducing complications.^{[5][6][7][8][9]} A 2021 meta-analysis found that bariatric surgery was associated with reduction in all-cause mortality among obese adults with or without type 2 diabetes.^[10] This meta-analysis also found that median life-expectancy was 9.3 years longer for obese adults with diabetes who received bariatric surgery as compared to routine (non-surgical) care, whereas the life expectancy gain was 5.1 years longer for obese adults without diabetes.^[10] The risk of death in the period following surgery is less than 1 in 1,000.^[11] A 2016 review estimated bariatric surgery could reduce all-cause mortality by 30-50% in obese people.^[1] Bariatric surgery may also lower disease risk, including improvement in cardiovascular disease risk factors, fatty liver disease, and diabetes management.^[12]

Stomach reduction surgery is frequently used for cases where traditional weight loss approaches, consisting of diet and physical activity, have proven insufficient, or when obesity already significantly affects well-being and general health.^[3][13] The weight-loss procedure involves reducing food intake. Some individuals might suppress bodily functions to reduce the absorption of carbohydrates, fats, calories, and proteins. The outcome is a significant reduction in BMI.^[3] The efficacy of stomach reduction surgery varies depending on the specific type of procedure.^[13] There are two primary divisions of surgery, specifically gastric sleeve surgery and gastric bypass surgery.^[3]

As of October 2022,^[update] the American Society of Metabolic and Bariatric Surgery and International Federation for the Surgery of Obesity recommended consideration of bariatric surgery for adults meeting two specific criteria: people with a body mass index (BMI) of more than 35 whether or not they have an obesity-associated condition, and people with a BMI of 30–35 who have metabolic syndrome.^[12][14] However, these designated BMI ranges do not hold the same meaning in particular populations, such as among Asian individuals, for whom bariatric surgery may be considered when a BMI is more than 27.5.^[12] Similarly, the American Academy of Pediatrics recommends bariatric surgery for adolescents 13 and older with a BMI greater than 120% of the 95th percentile for age and sex.^[15]