Harvard Health Letters

An operation that changes how the stomach and intestines digest food has been hailed as a potential lifesaver for people who are severely overweight. It can dramatically improve blood sugar, lower blood pressure and cholesterol, lessen sleep apnea (a dangerous pattern of breath holding during sleep), and improve heart function. But these benefits, which accrue only with a lifelong commitment to healthy eating and exercise, must be balanced against possible risks.

In general, the operation is intended for individuals with a body mass index of 40 or higher, or 35 and higher with severe, treatment-resistant problems such as diabetes. Recommendations from the International Diabetes Federation suggest that weight-loss surgery should be considered as a treatment for diabetes.

TYPES OF SURGERY

There are two main types of weight-loss surgery, which is also called bariatric surgery. Restrictive procedures like gastric band surgery shrink the functional size of the stomach to that of a walnut. This physically limits how much a person can eat at one time. Malabsorptive procedures, such as Roux-en-Y gastric bypass, shrink the stomach and create a bypass around part of the small intestine.

The bypass prevents the digestive system from absorbing some of the food that is eaten. This resets the body's appetite regulation system and accelerates the feeling of fullness that follows a meal. The operation is just the beginning. For it to work, a person must learn to eat in a whole new way and stick with the recommended diet.

Gastric bypass is one type of weight-loss procedure. The upper part of the stomach is made into a pouch the size of a walnut or egg. The small intestine is cut: one end is attached to the stomach pouch, the other to the bypass.

DRAMATIC BENEFIT FOR SOME, FAILURE FOR OTHERS

Many people lose half or more of their starting weight following one of these procedures, especially in the year or two after the operation. The average loss is 44 to 66 pounds.

This rapid weight loss quickly translates into improvements in blood sugar, blood pressure, and cholesterol levels in about nine out of 10 people. In some, the changes are so great that they can stop taking medicines for diabetes, high blood pressure, or high cholesterol. But these benefits last only as long as the weight stays off.

Most people who have the operation slowly regain some of their lost weight over several years. Up to one in six can't maintain the rigorous diet necessary to keep the weight off.

"People must make a commitment to lifelong change to benefit from this surgery," says Dr. George L. Blackburn, a nutrition and obesity expert at Harvard-affiliated Beth Israel Deaconess Medical Center, Boston, Mass. At the best surgical centers, multidisciplinary teams of surgeons, doctors, and nutritionists are available to help -- but it's up to the person who underwent the surgery to stick with the necessary changes. That's not easy.

RISKS AND COMPLICATIONS

Like any major operation, weight-loss surgery has risks. Death is one; about one person in 100 who undergoes weight-loss surgery dies within a month or so of the operation. Advanced age and other health problems increase the risk of dying.

It's important for readers to understand another risk that seems paradoxical: Although weight-loss surgery tends to improve heart health in the long run, in the short term the operation places a tremendous strain on the heart. Heart attacks and other cardiac problems account for as many as one in five post-surgery deaths. This likely reflects years of obesity-related damage to the heart and blood vessels.

Long-term complications of weight-loss surgery include nutritional deficiencies, a blockage in the stomach or intestines, leaking or contraction around the site of the operation, hernia, and depression. Because of these and other complications, lifelong medical surveillance is important.

Even with the risks, a statement from the American Heart Association supports weight-loss surgery for severely obese individuals who have not had success losing weight by traditional methods (Circulation). Why?

"Obesity can kill, too," says Dr. Blackburn. "If you decide to have weight-loss surgery, partner up with your doctors so the intervention is as successful as it can be."

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