Michelle Anderson of Greenville and Joan Johnson of Westford both know the direct weight-loss benefits of gastric bypass, because they both recently underwent the procedure.

But they didn't have to go all the way to Pittsburgh for the surgery. Dr. James Kolenich performed the surgery on both women at UPMC Horizon, Greenville.

Kolenich and Dr. Rodolfo Arreola Jr., both of Greenville Surgical Associates, both perform laparoscopic gastric bypasses locally.

"People are waiting in line at Cleveland and Pittsburgh," Kolenich said. "They don't realize they can have it done here."

The surgery involves separating a small section of the stomach with staples to create a pouch, then connecting a section of the small intestine to the pouch to allow food to bypass the first and second segments of the small intestine.

The Greenville surgeons just started doing the surgery laparoscopically this year.

The surgery works in two ways. It limits the food intake to about one ounce -- about the size of an egg or a plum -- and it prevents the food from being absorbed because it spends less time in the small intestines.

"Weight loss surgery is the ultimate cure for weight problems," Kolenich said. "When people get to a certain size, dieting is no longer effective."

When a person is 100 pounds or more overweight, the chance of dieting and keeping the weight off is under 5 percent, Kolenich said.

Both doctors said the surgery is done for health reasons, not to make someone thin.

Obesity increases the risk for heart disease, high blood pressure and adult on-set diabetes, which all add to the cost of medical coverage, Kolenich said.

Losing weight through surgery can improve all these conditions, and can also decrease health risks such as sleep apnea, asthma, menstrual irregularities in women and cancer.

To qualify for the surgery, a patient must be at least 100 pounds overweight, have health complications due to weight or have a body mass index of 35 or more. Body mass index is a calculation based on height and weight that determines body composition.

But to have the surgery, a patient has to have exhausted all other weight loss options.

"We encourage them to diet and exercise first and see a nutritionist. The insurance companies require you do this first," Kolenich said. "You certainly don't want to operate on a person who doesn't need an operation."

But, at a certain weight, dieting is not the answer.

"If they weigh 600 pounds, they can't exercise," Kolenich said. "By the time they lose 400 pounds, it could be 10 years. It's not going to have an impact."

After the surgery, the majority of weight loss occurs within the first two years. Weight may increase about 5 percent between five and 14 years after the surgery, but most of it stays off.

"The amount of weight they may put on is not significant," Arreola said. "The weight is coming off and staying off. It's a very, very effective procedure. They lose 60 to 80 percent of their excess weight."

But it's not an easy way out for patients looking to lose weight. The post-operative period can involve some major lifestyle changes.

Immediately after surgery, patients can only consume liquids, before moving on to pureed foods for six weeks. They also have to take vitamin, calcium and protein supplements, as not as many nutrients are absorbed into the body.

"They can't consume enough meat to give them adequate protein, especially early on," Kolenich said.

Once they move on to normal food again, Kolenich said patients basically have to "re-learn" how to eat.

"These people have to learn to sit down and take 45 minutes to eat a saucer-sized plate of food," he said.

Arreola added that those with sweet tooths may find that eating sugar is no longer a pleasurable experience.

"If you eat a high sugar concentrate, you're more likely to get abdominal pain and diarrhea," he said. This phenomenon is referred to as "dumping syndrome" and affects about two-thirds of gastric surgery patients.

"It will keep you from wanting to do it again," Arreola said.

Before performing the surgery, the surgeons ask their patients what their goals are.

"I ask the patients, what is it you would like to be able to do after surgery," Arreola said. "Some people can't even take their kids to a movie because they can't sit in a chair. The change in life is just amazing ... people who didn't even have jobs before are able to work. It's incredible how much their life changes. It's great to be a part of it."

You can e-mail Herald Staff Writer Erin Remai at eremai@sharon-herald.com.