Severe Obesity is a chronic condition that is difficult to treat through diet and exercise alone. Gastrointestinal surgery is the best option for people who are severely obese and cannot lose weight by traditional means or who suffer from serious Obesity-related health problems. The surgery promotes weight loss by restricting food intake and, in some operations, interrupting the digestive process. As in other treatments for Obesity, the best results are achieved with healthy eating behaviors and regular physical activity.

People who may consider gastrointestinal surgery include those with a body mass index (BMI) above 40-about 100 pounds of overweight for men and 80 pounds for women . People with a BMI between 35 and 40 who suffer from type 2 diabetes or life-threatening cardiopulmonary problems such as severe sleep apnea or Obesity-related heart disease may also be candidates for surgery. For those considering this, we offer free informational seminars as well as support groups for after surgery patients and families.

The concept of gastrointestinal surgery to control Obesity grew out of results of operations for cancer or severe ulcers that removed large portions of the stomach or small intestine.

Because patients undergoing these procedures tended to lose weight after surgery, some physicians began to use such operations to treat severe Obesity. The first operation that was widely used for severe Obesity was the intestinal bypass. This operation, first used 40 years ago, produced weight loss by causing malabsorption. The idea was that patients could eat large amounts of food, which would be poorly digested or passed along too fast for the body to absorb many calories. The problem with this surgery was that it caused a loss of essential nutrients and its side effects were unpredictable and sometimes fatal. The original form of the intestinal bypass operation is no longer used.

Gastrointestinal surgery for Obesity, also called bariatric surgery, alters the digestive process. The operations promote weight loss by closing off parts of the stomach to make it smaller. Operations that only reduce stomach size are known as “restrictive operations” because they restrict the amount of food the stomach can hold.

Some operations combine stomach restriction with a partial bypass of the small intestine. These procedures create a direct connection from the stomach to the lower segment of the small intestine, literally bypassing portions of the digestive tract that absorb calories and nutrients. These are known as malabsorptive operations.

Gastrointestinal surgery may be the next step for people who remain severely obese after trying nonsurgical approaches, or for people who have an obesity-related disease. Candidates for surgery have:

 
• a BMI of 40 or more  
• a life-threatening Obesity-related health problem such as diabetes, severe sleep apnea, or heart disease and a BMI of 35 or more  
• Obesity-related physical problems that interfere with employment, walking, or family function.

If you fit the profile for surgery, answers to the following questions may help you decide whether weight-loss surgery is appropriate for you.

Are you:
 

• unlikely to lose weight successfully with nonsurgical measures?  
• well informed about the surgical procedure and the effects of treatment?  
• determined to lose weight and improve your health?  
• aware of how your life may change after the operation (adjustment to the side effects of the surgery, including the need to chew well and inability to eat large meals)?  
• aware of the potential for serious complications, dietary restrictions, and occasional failures?  
• committed to lifelong medical follow-up?

Remember: There are no guarantees for any method, including surgery, to produce and maintain weight loss. Success is possible only with maximum cooperation and commitment to behavioral change and medical follow-up - and this cooperation and commitment must be carried out for the rest of your life.

Benefits and Risks

Surgery to produce weight loss is a serious undertaking. Anyone thinking about surgery should understand what the operation involves. Patients and physicians should carefully consider the following benefits and risks:

Benefits

 
• Right after surgery, most patients lose weight quickly and continue to lose for 18 to 24 months after the procedure. Although most patients regain 5 to 10 percent of the weight they lost, many maintain a long-term weight loss of about 100 pounds.  
• Surgery improves most Obesity-related conditions. For example, in one study blood sugar levels of 83 percent of obese patients with diabetes returned to normal after surgery. Nearly all patients whose blood sugar levels did not return to normal were older or had lived with diabetes for a long time.

Risks

 
• Ten to 20 percent of patients who have weight-loss surgery require follow-up operations to correct complications. Abdominal hernia was the most common complication requiring follow-up surgery, but laparoscopic techniques seem to have solved this problem. In laparoscopy, the surgeon makes one or more small incisions through which slender surgical instruments are passed. This technique eliminates the need for a large incision and creates less tissue damage. Patients who are superobese (>350 pounds) or have had previous abdominal surgery may not be good candidates for laparoscopy, however. Less common complications include breakdown of the staple line and stretched stomach outlets.  
• Some obese patients who have weight-loss surgery develop gallstones. Gallstones are clumps of cholesterol and other matter that form in the gallbladder. During rapid or substantial weight loss, a person’s risk of developing gallstones increases. Taking supplemental bile salts for the first 6 months after surgery can prevent gallstones.  
• Nearly 30 percent of patients who have weight-loss surgery develop nutritional deficiencies such as anemia, osteoporosis, and metabolic bone disease. These deficiencies usually can be avoided if vitamin and mineral intakes are high enough.  
• Women of childbearing age should avoid pregnancy until their weight becomes stable because rapid weight loss and nutritional deficiencies can harm a developing fetus.

Content provided by:
U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES
National Institutes of Health
NIH Publication No. 01-4006
December 2001