Not just for the rich and famous, such as Al Roker and Carnie Wilson, the American Society for Bariatric Surgery projects that a record 171,200 weight-loss surgeries were performed in the U.S. in 2005.

Doctors won't run out of patients anytime soon. At least 10 million Americans are heavy enough to be eligible for weight-loss surgery, meaning they're usually 100 pounds or more overweight. There are benefits to this surgery for those who are very obese. But gastric bypass and banding surgeries drastically--and permanently--change the digestive system.

Here's what the surgeries involve.


Gastric bypass surgery

This procedure accounts for about 80 percent of weight-loss surgeries in the U.S.

What's involved. The digestive system is permanently rerouted; patients are left with a 1- to 2-tablespoon stomach pouch, created with staples, and food is detoured around the upper 20 to 60 inches of small intestine. Once performed only as open surgery, with 8- to 10-inch incisions that are risky for the very obese, gastric bypass is increasingly performed with a laparoscope, an instrument operated remotely through four or five small incisions.

The end result. Bypass patients feel full after eating tiny portions of food, and their shortened intestinal tract doesn't completely absorb vitamins and minerals. For at least a year after surgery, patients have "dumping syndrome"--with symptoms that can include nausea, diarrhea, and dizziness--within minutes of eating cookies or high-carb foods.


Adjustable gastric banding

This surgery is newer on the scene (it has been approved in the U.S. since 2001), but is the most often performed weight-loss surgery in the rest of the world.

What's involved. Using a laparoscope, the surgeon straps an inflatable silicon cuff around the stomach, creating a small pouch at the top with a restricted opening to the rest.

The end result. The pouch fills quickly and empties slowly, creating a feeling of fullness. Overfilling of the stomach causes undigested food to back up into the esophagus, an unpleasant sensation that patients learn to avoid by eating little at a sitting and chewing thoroughly. If a patient is losing weight too quickly or too slowly, the doctor loosens or tightens the cuff by using a syringe to adjust the amount of saline solution in a port implanted under the skin.

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