The findings - released last month from long-term studies of 20,000 dangerously overweight people in Utah and Sweden - were stunning: Obese patients who had undergone stomach reduction surgery were up to 40 percent more likely to live longer, 56 percent less likely to die of heart disease, and 92 percent less likely to die from diabetes than those who tried diet and exercise alone.
Yet for Tina Fisher, program coordinator for the new Center for Weight Loss Surgery at Newton-Wellesley Hospital, the studies only confirmed what she already knew.
In the six years since her own gastric bypass surgery, the 30-year-old nurse practitioner has lost 137 pounds. She exercises four times a week, can fit into a standard movie theater seat, and sometimes forgets what her old life was like.
A roller-coaster enthusiast, Fisher used to watch her husband ride alone because she was worried whether the seat belt or safety bar would fit around her 297-pound frame.
She also suffered from the litany of health woes common to the very overweight: diabetes, joint problems, and sleep apnea, a disorder in which a person literally stops breathing repeatedly during sleep.
"Patients come back and tell me about their experiences, like the first time they didn't have to go into a plus-size clothing store," she said. "And I think, 'Oh yeah, I remember that.' "
Thanks to stories like Fisher's, officials at Newton-Wellesley said they were convinced that gastric bypass operations represent a sound medical option and were aggressively expanding their weight loss surgery practice even before the new findings were released.
Last year, the hospital's bariatric surgery program was accredited to operate on even the most severely obese patients, and in June, the program was elevated to a full-fledged department and renamed the Center for Weight Loss Surgery.
As it turns out, the timing of the hospital's push could not have been better, officials said.
"It's a great step forward," Dr. Sheila Partridge, a surgeon at the center, said of the findings. "We always knew we were improving people's lives. We could see it. But we didn't have the peer-reviewed proof."
Doctors at Newton-Wellesley have performed more than 2,000 surgeries since the center was established in 2005, 270 in the last year alone.
Officials say the program has had a 95 percent rate of success, which is defined as a patient who loses at least 65 percent of his or her excess weight and maintains that loss. To qualify for the surgery, patients must be diagnosed as morbidly obese, meaning at least 100 pounds over the ideal weight for their height.
The doctors at Newton-Wellesley perform a surgery called the laparoscopic roux-en-y gastric bypass. The minimally invasive procedure reroutes the patient's gastrointestinal tract, bypassing most of the stomach and the small intestine. The patient is left with a pouch that initially holds just two ounces of food or liquid by volume - about the same as a newborn's stomach.
Partridge said that the surgery has been particularly successful because it not only limits food intake, but as studies have shown, it also prevents the stomach from sending chemical signals that the brain interprets as hunger.
After surgery, patients begin on a liquid-only diet and gradually work their way through pureed foods to solid food in smaller, more frequent portions.
Weight loss and health improvements can be immediate and dramatic. It is not uncommon for patients to enter the hospital for their surgery with diabetes and leave four days later without it.
"Patients call their surgery date their new birth date," Partridge said. "I remember how awestruck I was when I first witnessed a baby being born. This feels as awesome as that."
The physical changes are so striking that the doctors and nurses at the center sometimes hold an impromptu huddle when a patient walks through the door for a one- or two-year follow-up appointment, Fisher said, to figure out who they are.
Partridge cautions, however, that the operation is not a quick fix. Patients must commit to an altered lifestyle for essentially the rest of their lives. Even with reduced cravings for food, patients must battle strong emotional attachments to food, and doctors at Newton-Wellesley frequently refer to obesity as a chronic disease more akin to cancer than a condition caused by overeating.
That is one of the reasons, Partridge said, that the center does not offer lap-band surgery, which is heavily advertised on television and which many patients request.
Lap-band uses a removable silicone ring that is placed around the upper part of the stomach and filled with saline, creating a smaller pouch that can only hold a small amount of food.
"We don't believe in it," Partridge said. "It's basically a reversible treatment for a chronic disease."
On a recent weekday, the center's waiting room held reminders of the challenges that chronically overweight people face.
One coffee table held a hospital-produced scrapbook containing some 60 gastric-bypass success stories, including one 35-year-old nurse who lost 336 of her 521 pounds after the surgery.
Right next to it was a recent issue of People magazine touting the recent weight loss of actresses Valerie Bertinelli and Kirstie Alley (both paid spokeswomen for the Jenny Craig weight loss program), with the headline: "From Fat to Fab! Two pals dish about finding the willpower and feeling good about their bodies."
To help with the emotional impact, patients are required to meet with psychologists and nutritionists even before their surgery takes place.
Dale Powers, a 50-year-old compliance officer for a large financial services firm, will be having the surgery this Saturday.
Doctors say Powers, who weighs 337 pounds, is a textbook example of a patient who can most benefit from the surgery.
A former youth baseball player and musician who still helps coordinate marching band and drill corps competitions, he has battled his weight vigorously in his adult years.
"I lost 100 pounds two different times, and 60 pounds on another four occasions," he said. "I've tried Weight Watchers, Overeaters Anonymous, Jenny Craig . . . I don't have any regrets about my efforts."
Even as those efforts failed, Powers said he was still leery of surgery.
A sports fan, he had followed the lawsuit filed by former New England Patriots coach Charlie Weis, who suffered life-threatening complications after weight-loss surgery at Massachusetts General Hospital. Even though Weis lost the lawsuit, Powers even went so far as to read the transcripts from the trial.
Already suffering from sleep apnea and joint pain, Powers said he finally made the decision to have surgery after a recent annual physical.
If he didn't do something about his weight, his doctor said, it was almost certain he would have diabetes.
"That was it for me," Powers said. "I don't want to be old at 65. There's a lot of life ahead of me."