Bariatric surgery procedures include gastric bypass, sleeve gastrectomy, gastric band and duodenal switch. These operations have proven results in treating class III obesity. They also help normalize your metabolism, including blood sugar, blood pressure and cholesterol.
Bariatric surgery, also called weight loss surgery, is a category of surgical operations intended to help people with obesity lose weight. Healthcare providers may recommend bariatric surgery if other weight loss methods have failed and if obesity appears to pose a greater risk to your health than surgery.
Bariatric surgery procedures work by modifying your digestive system — usually your stomach, and sometimes also your small intestine — to regulate how many calories you can consume and absorb. They can also reduce the hunger signals that travel from your digestive system to your brain.
These procedures can help treat and prevent many metabolic diseases related to obesity, including diabetes and fatty liver disease. But weight loss surgery isn't an easy “quick fix”. It requires preparation beforehand and long-term lifestyle changes afterward to be successful.
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Bariatric surgery is the most successful long-term treatment for class III obesity. According to the National Institutes of Health (NIH), it is nearly impossible for people with class III obesity to sustain weight loss through diet and exercise alone. Once your body has registered your higher weight as “normal,” it continues to try to return to that weight. Bariatric surgery works by changing how your body manages what you eat, allowing healthy diet and lifestyle changes to be effective for sustained weight loss and health.
Obesity is associated with many chronic diseases, many of which can be life-threatening. These conditions and risk factors greatly improve after surgery and weight loss. If you're a candidate for bariatric surgery, you may already have or be at risk of developing any of these diseases, including:
Bariatric surgery requirements begin with establishing a diagnosis of class III obesity. That means that you either:
The criteria are slightly higher for adolescents. An adolescent may be a candidate if they have:
While BMI is easily measured, you may have to take some medical tests to diagnose your obesity-related health conditions.
Before scheduling your bariatric surgery, your healthcare provider will want to ensure that you’re physically and mentally fit for the surgery. You’ll meet with a team of specialists who will counsel you about the risks and benefits while evaluating your physical and mental health.
You may need to pass medical screening tests to make sure the surgery is safe for you. If you use tobacco, drugs or excessive alcohol, you’ll be required to quit before qualifying for surgery. Your healthcare team can help you with this.
Your surgeon may also ask you to follow a pre-bariatric surgery diet for a few weeks to prepare for your operation. This is to reduce the fat inside your abdomen, where the operation will take place, making the operation safer and reducing the risk of complications. Your surgeon will give you specific guidelines to follow.
Weight loss surgery is usually performed through minimally invasive methods (laparoscopic surgery). That means small incisions, faster healing and less pain and scarring than you would have with traditional open surgery. Very rarely, some patients are better treated with open surgery due to their specific conditions.
The gastric sleeve, also called sleeve gastrectomy, is the most commonly performed bariatric surgery in the U.S. This may be because it’s a relatively simple procedure that's safe to perform on most people with little risk of complications. The gastrectomy simply removes a large portion of your stomach — about 80% — leaving behind a small, tubular portion, like a sleeve. This naturally reduces the amount of food you can consume in one sitting and makes you feel fuller faster. But it also reduces the hunger hormones that are normally produced in your stomach. This helps to stabilize your metabolism, decreasing your appetite and regulating your blood sugar.
The gastric bypass is also known as the “Roux-en-Y," which is a French term meaning “in the form of the letter Y.” With this procedure, your small intestine will end up in that form. First, surgeons create a small pouch at the top of your stomach, separating it from the lower portion with surgical staples. Then they divide your small intestine and bring the new segment up to connect to the stomach pouch. Food will now flow through the new, smaller stomach and lower segment of your small intestine, bypassing the rest. This restricts how much your stomach can hold and also how much nutrition your small intestine can absorb. Restricting the small intestine makes this method more effective than gastric restriction alone.
This is the original version of the duodenal switch, an operation that combines a sleeve gastrectomy with an intestinal bypass. (It sometimes goes by a shorter name: Gastric Reduction Duodenal Switch). It’s similar to the Roux-en-Y gastric bypass but more extreme. This operation bypasses most of your small intestine — about 75%. This significantly reduces the hunger hormones produced in your small intestine as well as in your stomach. It also significantly restricts how much nutrition your small intestine can absorb. This is what makes the duodenal switch the most effective surgery for weight loss and for improving metabolic syndromes like diabetes. But it can also make it hard for your body to absorb enough nutrients to stay healthy.
This newer procedure is a modified version of the original duodenal switch, intended to reduce complications. It also goes by the names Loop Duodenal Switch or SADI-s. Early results are still being studied, but so far it appears promising that this version may eventually replace the original duodenal switch. Like the original, it begins with a sleeve gastrectomy, then divides the first part of the small intestine just after the stomach (the duodenum). This time, the small intestine is reattached as a loop, which requires just one surgical connection (anastomosis) instead of two. It also means that less of the small intestine is bypassed, allowing for a little more absorption of nutrients.
During the first year after your surgery, your healthcare provider will see you regularly for follow-up visits and testing. They will take metabolic blood tests to monitor how your health is improving and screen for any nutritional deficiencies. After the first year, if you're in good health and have lost a lot of weight, you may want to discuss body contouring options with your healthcare provider. Body contouring can help remove excess skin folds and tighten loose tissues.
Most people — about 90% — lose about 50% of their excess weight after bariatric surgery, and keep it off. Different procedures have slightly different results. The average weight loss after gastric bypass is about 70% of excess body weight. After a duodenal switch, it’s about 80%. Weight loss after sleeve gastrectomy ranges between 30% and 80%. These results are measured after a period of 18 to 24 months.
When weighing the pros and cons of bariatric surgery, it’s important to consider the risks of the operation itself as well as the possible side effects that may occur afterward.
All surgeries involve certain risks. Longer and more complex operations may involve more. Risks include:
Surgeries that modify your digestive system can cause certain digestive complications. These are sometimes called post-gastrectomy syndromes. Possible complications include:
You’ll likely spend a few days recovering in the hospital, then a few weeks recovering at home before you feel ready to go back to work. You may need to avoid strenuous activity for up to six weeks, and it may take up to 12 weeks to resume a normal diet.
Weight loss surgery is considered successful if you lose 50% of your excess weight and keep it off. By this standard, the success rate is 90%. Many people experience steady weight loss for the first two years, then stall or regain some weight after that. Usually, the weight regained is less than 25%.
A note from Cleveland Clinic
Bariatric surgery offers a much-needed, long-term solution to a difficult, progressive disease. Obesity is very hard to beat, and without intervention, it has heavy effects on your health, quality of life and lifespan. Bariatric surgery can change the biological factors that make it so hard for people with obesity to lose weight and keep it off. While surgery can have its own risks and complications, in most cases these are much lower than the risks and complications that come with obesity and its related diseases.
Last reviewed by a Cleveland Clinic medical professional on 06/09/2022.
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