Severe obesity is a chronic condition that is hard to treat with diet and exercise alone. Bariatric surgery is an operation on the stomach and/or intestines that helps patients with extreme obesity to lose weight. This surgery is an option for people who cannot lose weight by other means or who suffer from serious health problems related to obesity. The surgery restricts food intake, which promotes weight loss and reduces the risk of type 2 diabetes. Some surgeries also interrupt how food is digested, preventing some calories and nutrients, such as vitamins, from being absorbed. Recent studies suggest that bariatric surgery may even lower death rates for patients with severe obesity. The best results occur when patients follow surgery with healthy eating patterns and regular exercise.
Bariatric Surgery for Adults
Currently, bariatric surgery may be an option for adults with severe obesity. Body mass index (BMI), a measure of height in relation to weight, is used to define levels of obesity. Clinically severe obesity is a BMI > 40 or a BMI > 35 with a serious health problem linked to obesity. Such health problems could be type 2 diabetes, heart disease, or severe sleep apnea (when breathing stops for short periods during sleep).
The Food and Drug Administration (FDA) has approved use of an adjustable gastric band (or AGB) for patients with BMI > 30 who also have at least one condition linked to obesity, such as heart disease or diabetes.
Who is a good adult candidate for surgery?
Having surgery to produce weight loss is a serious decision. Anyone thinking about having this surgery should know what it involves. Answers to the following questions may help patients decide whether weight-loss surgery is right for them.
Is the patient:
- Unlikely to lose weight or keep it off over the long term using other methods?
- Well informed about the surgery and treatment effects?
- Aware of the risks and benefits of surgery?
- Ready to lose weight and improve his or her health?
- Aware of how life may change after the surgery? (For example, patients need to adjust to side effects, such as the need to chew food well and the loss of ability to eat large meals.)
- Aware of the limits on food choices, and occasional failures?
- Committed to lifelong healthy eating and physical activity, medical follow-up, and the need to take extra vitamins and minerals?
There is no sure method, including surgery, to produce and maintain weight loss. Some patients who have bariatric surgery may have weight loss that does not meet their goals. Research also suggests that many patients regain some of the lost weight over time. The amount of weight regain may vary by extent of obesity and type of surgery. Habits such as snacking often on foods high in calories or not exercising can affect the amount of weight loss and weight regain. Problems that may occur with the surgery, like a stretched pouch or separated stitches, may also affect the amount of weight loss.
Success is possible. Patients must commit to changing habits and having medical follow-up for the rest of their lives.
Bariatric Surgery for Youth
Rates of obesity among youth are high. Bariatric surgery is sometimes used to treat youth with extreme obesity. Although it is becoming clear that teens can lose weight after bariatric surgery, many questions still exist about the long-term effects on teens' developing bodies and minds.
Who is a good youth candidate for surgery?
Experts in childhood obesity and bariatric surgery suggest that families consider surgery only after youth have tried for at least 6 months to lose weight and have not had success. Candidates should meet the following criteria:
- Have extreme obesity (BMI > 40 )
- Be their adult height (usually at age 13 or older for girls and 15 or older for boys)
- Have serious health problems linked to weight, such as type 2 diabetes or sleep apnea, that may improve with bariatric surgery
In addition, health care providers should assess potential patients and their parents to see how emotionally prepared they are for the surgery and the lifestyle changes they will need to make. Health care providers should also refer young patients to special youth bariatric surgery centers that focus on meeting the unique needs of youth.
Mounting evidence suggests that bariatric surgery can favorably change both the weight and health of youth with extreme obesity. Over the years' gastric bypass surgery has been the main operation used to treat extreme obesity in youth. An estimated 2,700 youth bariatric surgeries were performed between 1996 and 2003. A review of short-term data from the largest inpatient database in the United States suggests that these surgeries are at least as safe for youth as adults. As yet, AGB has not been approved for use in the United States for people younger than age 18. However, favorable weight-loss outcomes after AGB for youth have been reported abroad.
The Normal Digestive Process
Normally, as food moves along the digestive tract, digestive juices and enzymes digest and absorb calories and nutrients. After we chew and swallow our food, it moves down the esophagus to the stomach, where a strong acid continues the digestive process. The stomach can hold about 3 pints of food at one time. When the stomach contents move to the duodenum (the first part of the small intestine), bile and pancreatic juice speed up digestion. Most of the iron and calcium in the food we eat is absorbed there. The other two parts of the nearly 20 feet of small intestine absorb nearly all of the remaining calories and nutrients. The food particles that cannot be digested in the small intestine reside in the large intestine until eliminated.
How does surgery promote weight loss?
Bariatric surgery restricts food intake, which leads to weight loss. Patients who have bariatric surgery must commit to a lifetime of healthy eating and regular exercise. These healthy habits may help patients maintain weight loss after surgery.
Types of Bariatric Surgery
The type of surgery that may help an adult or youth depends on a number of factors. Patients should discuss with their health care providers what kind of surgery is suitable for them.
For additional information, go to http://win.niddk.nih.gov/publications/gastric.htm
The Weight-control Information Network (WIN) is a national information service of the National Institute of Diabetes and Digestive and Kidney Diseases of the National Institutes of Health, which is the Federal Government's lead agency responsible for biomedical research on nutrition and obesity. Authorized by Congress (Public Law 103-43), WIN provides the general public, health professionals, the media, and Congress with up-to-date, science-based health information on weight control, obesity, physical activity, and related nutritional issues.
U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES
National Institutes of Health
Adapted from NIH Publication No. 08-4006
Updated June 2011
Reviewed by athealth on January 29, 2014