Surgery for Severe Obesity Endorsed by Federal Panel : Health: Techniques partly bypass stomach or staple off part of it. Report says diet and exercise should be tried first.

A federal advisory panel on Wednesday endorsed gastrointestinal surgery to treat severe obesity but recommended that patients first try non-surgical weight loss techniques such as diet, exercise and behavior modification.

The panel, convened by the National Institutes of Health, called the two most commonly performed surgeries “meaningful and viable” options for achieving weight loss for many patients but urged that more research be conducted on the procedures.

“We are impressed with the progress made by the field over the last 10 to 15 years,” said Dr. Scott M. Grundy, chairman of the panel and director of the center for human nutrition at the University of Texas Southwestern Medical Center.

The panel estimated that more than 1.5 million Americans are severely obese, as determined by a formula known as the body mass index. The index is calculated by dividing a patient’s weight in kilograms by the square of the person’s height in meters. (A kilogram is 2.2046 pounds; a meter is 39.37 inches.)

Those with an index greater than 40 are considered severely obese, the panel said, and may be candidates for the surgery. An average adult male with an index of 40 is 100 or more pounds overweight; an average woman with an index of 40 is at least 80 pounds overweight.

An additional 4 million Americans have indexes of between 35 and 40, the panel said, meaning that they are 50 to 100 pounds overweight. A normal index value ranges between 20 and 25.

Obesity has been associated with cardiovascular disease, especially high blood pressure, diabetes, gallbladder disease, reduced blood levels of beneficial HDL cholesterol, an increase in certain types of cancers and emotional disorders.

The panel said that gastrointestinal surgery can induce “significant” weight loss in severely obese patients. In addition, the subsequent weight loss often causes an improvement in conditions related to obesity, such as diabetes, high blood pressure, disturbances of heart and lung function and arthritic symptoms in weight-bearing joints, the committee said.

But the surgery “is a matter of control, not cure,” said Dr. Jeremiah A. Barondess, president of the New York Academy of Medicine and a panel member. “Patients don’t lose weight indefinitely,” he said.

One of the surgeries, vertical-banded gastroplasty--commonly known as “stomach stapling”--reduces the volume of the stomach so that less food can enter. A small pouch is made by stapling off a large section of the stomach, creating a narrow, restricted pathway to the intestinal tract.

The other technique, gastric bypass, creates a small pouch at the upper part of the stomach and attaches a Y-shaped section of small bowel to serve as the outlet from the stomach to the intestinal tract, enabling some of the food to actually bypass the stomach.

The surgery is considered safe, although complications can occur, the panel said. These include leaks from the staple or suture lines, diarrhea, persistent vomiting, ulcers and gallstones. Also, the panel said, some patients fail to lose weight and may require a second operation.

Because nearly 80% of severely obese people who undergo the surgery are women of childbearing age, the panel recommended that they avoid pregnancy until their weight has stabilized after surgery.