Metabolic Surgery
Metabolic surgery is a type of operation that changes your digestive system to help you lose weight and improve serious health conditions related to obesity, including type 2 diabetes and heart disease.
Table of contents
- What Is Metabolic Surgery?
- Who Might Need Metabolic Surgery?
- Types of Metabolic Surgery
- Benefits of Metabolic Surgery
- Risks and Side Effects
- Life After Surgery
- How Effective Is It?
bariatric surgery, weight-loss surgery
What Is Metabolic Surgery?
Metabolic surgery, also called bariatric surgery or weight-loss surgery, is an operation that makes changes to your digestive system to help you lose weight and improve your overall health[1]. The term metabolic surgery is now preferred because these operations have powerful effects on your body’s metabolism, which is the chemical process by which your body converts food into energy[5].
These procedures work by modifying your digestive system, usually your stomach and sometimes also your small intestine, to control how many calories you can consume and absorb[6]. The surgery is performed using small incisions through minimally invasive surgical techniques, such as laparoscopic and robotic surgery, which allow patients to have a better overall experience with less pain, fewer complications, shorter hospital stays and a faster recovery[4].
While metabolic surgery is designed to treat obesity, these operations are very effective in treating many other diseases including diabetes, high blood pressure, sleep apnea and high cholesterol[4]. These operations also have an ability to prevent future health problems[4].
Who Might Need Metabolic Surgery?
Metabolic surgery may be an option for you if you have a body mass index (BMI) of 40 or higher, which is called extreme obesity[2]. Your BMI is a ratio of your height to weight that helps determine if you are at a healthy weight. The surgery may also be considered if your BMI is 35 to 39.9 and you have a serious weight-related health problem, such as type 2 diabetes, high blood pressure, or severe sleep apnea[2].
Some patients with a BMI of 28 to 30 and uncontrolled diabetes who are not able to manage their condition with diet and exercise alone may also be considered for metabolic surgery[5]. Bariatric surgery is often recommended only after you have tried to lose weight by improving your diet and exercise habits[2].
Healthcare providers may recommend metabolic surgery if other weight loss methods have failed and if obesity appears to pose a greater risk to your health than surgery[6]. According to the National Institutes of Health, it is nearly impossible for people with severe obesity to sustain weight loss through diet and exercise alone[6].
Types of Metabolic Surgery
Several different types of metabolic surgery procedures are available. Each surgery has its own advantages and potential drawbacks, and your surgeon will review your health history and work with you to determine which surgery is best for you[4].
Sleeve gastrectomy, often called the “sleeve,” is performed by removing approximately 80% of the stomach[4]. The remaining stomach is the size and shape of a banana. This has become the most common operative procedure worldwide because of its ease and effectiveness[12]. The new stomach holds less food and liquid, helping reduce the amount of food and calories that are consumed. By removing the portion of the stomach that produces most of the hunger hormone, the surgery decreases hunger and increases fullness[4].
Gastric bypass, specifically the Roux-en-Y gastric bypass, involves creating a small pouch in the upper stomach which is connected directly to the small intestine[5]. This procedure both limits the amount of food you can eat and reduces the absorption of nutrients and calories[4].
Biliopancreatic diversion with duodenal switch (BPD/DS) is a procedure that involves forming a tubular stomach which is connected directly to the last part of the intestine[5]. Although this is the most effective metabolic procedure, it is infrequently used because of higher rates of postoperative and long-term complications[12].
The choice of procedure depends on your concurrent medical conditions, patient preference, and the expertise of the surgeon[7]. For example, gastric bypass is better than sleeve gastrectomy for patients with gastroesophageal reflux disease[7].
Benefits of Metabolic Surgery
Metabolic surgery is done to help you lose extra weight and reduce your risk of possibly life-threatening weight-related health problems[2]. The benefits allow patients with obesity who choose to undergo treatment to enjoy a better quality of life and a longer lifespan[4].
Studies show that metabolic surgery may reduce a patient’s risk of premature death by 30 to 50 percent[3]. In patients who have had metabolic surgery, overall mortality is reduced by 30 to 45 percent at two to 15 years after surgery compared with patients with obesity who did not have surgery[7].
On average, patients lose 26 kilograms (57 pounds) more than those with nonsurgical weight loss[7]. Patients typically lose the most weight one to two years after surgery and may lose as much as 60 percent of excess weight six months after surgery, and 77 percent of excess weight as early as 12 months after surgery[3].
The majority of patients with obesity-related diseases experience significant improvement or remission. Approximately 70 percent of surgical patients achieve remission of type 2 diabetes, and over 30 percent of surgical patients maintain remission at 10 years[7]. The remission rates for other conditions include: type 2 diabetes at 92 percent, hypertension at 75 percent, obstructive sleep apnea at 96 percent, dyslipidemia at 76 percent, and cardiovascular disease at 58 percent[3].
These procedures also help normalize your metabolism, including blood sugar, blood pressure and cholesterol[6]. The benefits of metabolic surgery include better control of blood pressure and blood glucose levels, improvement of triglycerides and lipids, long-term sustainable weight loss, improved function of gastrointestinal hormones, and reduced risk of diabetic complications such as kidney failure, eye disease, and vascular problems[5].
Because of the reduction or elimination of obesity-related conditions and associated treatment costs, estimates suggest that insurance companies will recover surgery costs within two to four years, and healthcare costs are reduced by 29 percent within five years of bariatric surgery[3].
Risks and Side Effects
While metabolic surgery can offer many benefits, all forms of weight-loss surgery are major procedures that can pose risks and side effects[2]. However, these operations are extremely safe, with complication rates that are lower than common operations such as gallbladder removal, hysterectomy, and hip replacement[4].
The risk of death associated with metabolic surgery is about 0.1 percent and the overall likelihood of major complications is about 4 percent[3]. These procedures have a mortality risk of 0.2 to 0.3 percent[7]. The risks of severe obesity outweigh the risks of metabolic surgery for many patients[3].
Common side effects include surgical complications, nutritional deficiencies, bone density loss, dumping syndrome, gastroesophageal reflux disease, and loose skin[7]. Dumping syndrome is a rapid emptying of sugars from your stomach into your small intestine, which can cause bloating, low blood sugar and diarrhea[7]. Initial treatment for dumping syndrome includes eating small, frequent meals, avoiding fluids with meals, and avoiding rapidly absorbed sugars[7].
After metabolic surgery, patients require standardized nutritional supplementation and surveillance[7]. Patients who do not take vitamins every day for life can suffer severe and even life-threatening medical problems due to low vitamin and mineral levels[16]. After surgery, patients should avoid nonsteroidal anti-inflammatory drugs and take daily vitamin supplements indefinitely[7].
All bariatric operations induce a high bone turnover state, with declining bone mineral density and increased fracture risk[15]. Appropriate strategies include adequate calcium and vitamin D supplementation and targeted bone mineral density screening[15].
Life After Surgery
Metabolic surgery is not an easy quick fix[6]. It requires preparation beforehand and long-term lifestyle changes afterward to be successful[6]. Weight-loss surgery can start you on the path to a healthier, longer and more fulfilling life, but it is not a cure for obesity—rather, it is a tool to help you lose weight[17]. Long-term success depends on your ability to follow guidelines for diet, exercise and lifestyle changes[17].
After bariatric surgery, your daily regimen will include short-term and long-term medications[17]. You may need to take medication to reduce the risk of developing ulcers in the digestive tract for six months after surgery or indefinitely, as directed by your surgical team. To prevent vitamin and mineral deficiencies, you will need to take a bariatric-specific multivitamin and calcium supplements indefinitely[17].
Following metabolic surgery, laboratory studies should be completed every three months for the first year after surgery, then annually[7]. For patients with type 2 diabetes, early and dramatic improvements in glucose control require anticipatory management, including insulin dose reductions, discontinuation of certain oral medications, and close monitoring[15].
The digestive system requires time to adapt after surgery. For the first week, you will be on a full-liquid diet consisting of protein shakes and water[20]. Most patients will start out on a liquid diet for some weeks, then slowly start to take soft foods, and then eventually solid foods[16]. You can usually start eating regular foods about six to eight weeks after surgery[21].
Immediately after surgery, be prepared to feel extremely full because your stomach capacity has been greatly reduced[18]. Patients will need to drink 64 ounces of fluids or more to avoid nausea, kidney problems, constipation and fatigue[16]. In addition to staying hydrated, patients will need to focus on how much protein they take in, with most programs recommending 60 to 100 grams per day[16].
Patients should prioritize protein at meals, limit simple carbohydrates and sugars, and avoid processed and high-fat foods, alcohol and carbonated beverages[20]. Avoid foods with high amounts of sugar and starch, and stay away from bread, rice and pasta because these carbohydrate sources tend to swell and create a heavy, uncomfortable feeling in your stomach[18].
Exercise is encouraged and can help maintain weight loss long-term[16]. Light physical activity, such as walking, is recommended within the first few hours after surgery and should be done twice a day for 20 minutes[20]. Once patients feel ready, exercise should be done with the goal of 30 minutes per day of moderate activity on average[16].
Persistent changes in diet, such as consuming protein first at every meal, regular physical activity, and ongoing attention to behavior change are critical for success after metabolic surgery[7]. Long-term strategies to prevent weight regain include adherence to comprehensive lifestyle interventions and identification and avoidance of medications that promote weight gain[15].
Patients should be counseled to delay pregnancy for at least 12 to 24 months after metabolic surgery[7]. After weight-loss surgery, you may experience a range of emotions, and it’s common to have feelings of frustration or depression[20]. Often, patients don’t fully understand the role food has played in their lives until after they’ve had the surgery[18].
How Effective Is It?
Metabolic surgery is the most effective and long-lasting treatment for severe obesity, resulting in significant weight loss and the improvement, prevention or resolution of many related diseases[3]. According to the National Institutes of Health, bariatric surgery is the most successful long-term treatment for severe obesity[6].
Studies show patients typically lose the most weight one to two years after surgery and see substantial weight improvements in obesity-related conditions[3]. On average, weight loss of 30 to 50 kilograms (66 to 110 pounds), or a 20 to 30 percent reduction in total body weight, is achieved, although most patients will experience some weight regain three to 10 years after surgery[7]. On average, five years after surgery, patients maintain 50 percent of their excess weight loss[3].
Patients who have metabolic surgery are five times more likely to experience remission of diabetes compared to those with nonsurgical weight loss[7]. Metabolic surgery is an effective treatment option for type 2 diabetes[7].
In 2019, approximately 256,000 metabolic surgery procedures were performed in the United States, a 32 percent increase since 2014[7]. The most common procedures are the laparoscopic sleeve gastrectomy and the Roux-en-Y gastric bypass[7]. In 2019, sleeve gastrectomy accounted for 59.4 percent of procedures, gastric bypass for 17.8 percent, and revisions for 16.7 percent[3].
The average cost of bariatric surgery ranges between $17,000 and $26,000[3]. Bariatric surgery is as safe or safer than some of the most commonly performed surgeries in America including gallbladder surgery, appendectomy and knee replacement[3].