Alicia Chang, AP

For nearly a decade, Cristina Iaboni tried to tame her diabetes the usual way, through daily shots of insulin and other medicine. Still, her blood sugar raged out of control. So Iaboni combed the internet for another solution. She found a doctor who is testing weight loss surgery on diabetics who, like herself, are overweight in an attempt to curb the disease.

Scientists in recent years have discovered that diabetes all but disappears in some obese patients soon after the operation. Many were able to achieve normal blood sugar and ditch their medications. But does the benefit extend to diabetics who are not quite as hefty? Iaboni's surgeon is one of a handful around the world stretching the rules to see if the weight loss operation helps.

Iaboni had gastric bypass surgery last fall. Now 50 pounds lighter, she has stopped taking diabetes medications. Her blood sugar is almost normal. “I didn't care if I lost any weight. I just wanted the diabetes to go away,” said the 45-year-old Connecticut mother of two teenagers.

The twin epidemics of obesity and diabetes are fueling an international public health threat. In the United States, one out of five people with obesity-linked Type 2 diabetes are morbidly obese — defined as 100 pounds overweight. Surgery is generally a last resort after traditional ways to shed the pounds fail. Even so, there are strict rules for who can go under the knife.

Federal guidelines say surgery candidates must be morbidly obese with a body mass index over 40, or a BMI over 35 plus a weight-related medical problem like diabetes or high blood pressure. Insurers use the cutoffs in deciding whether to pay for the procedure.

Dr. Philip Schauer of the Cleveland Clinic is among those pushing the BMI envelope. For a study, he's recruiting 150 overweight and obese Type 2 diabetics with BMIs between 27 and 43. Some will have surgery and their progress will be compared to those who manage their diabetes with medicine. The goal is to see which group can achieve complete remission.

Smaller studies have hinted that stomach stapling and gastric banding  may work in diabetics who aren't so fat. “These procedures can cause long-term remission and restore someone to normal blood sugar levels without medication,” Schauer said.

How does the surgery help some diabetics beat the disease? Doctors don't exactly know, but there is some evidence that it may not all be due to weight loss. Diabetes occurs when the body can't regulate blood sugar, and some researchers think that the rerouting of the digestive tract after the operation affects the gut hormones involved in blood sugar control.

Last year, 220,000 people had obesity surgery, which can cost between $14,000 and $26,000, according to the American Society for Metabolic and Bariatric Surgery. The surgery is fairly safe. In a 2009 study, death, serious complications or the need for a repeat procedure occurred in one percent who received bands, about five percent who had minimally invasive gastric bypass and around eight percent who had traditional bypass.

The American Diabetes Association said there's not enough evidence to generally recommend surgery for diabetics with a BMI lower than 35 outside of an experiment. That's how Iaboni got the procedure. At 5-foot-5 and 191 pounds, she was obese with a BMI of 31.8, but not heavy enough to qualify for regular surgery under the federal BMI limits. She paid $30,000 for the surgery and hospital stay to be part of the study.

Before the operation, she would be nauseated from the diabetes medications and felt lousy all the time. When people learn that she had surgery, many react in surprise. “They would say, ‘You're not heavy. Why would you do this?’ People thought I did it for the weight loss,” Iaboni said.

Her surgeon, Dr. Francesco Rubino, has been pleased with her progress so far. He has plans to operate on two others as early as this month. Eventually, he hopes to enroll 50 patients with Type 2 diabetes and track if their diabetes goes away after surgery. “It's important to tell patients this is a promising option, but of course we can't promise this is the cure for diabetes for everybody,” he said.

According to the diabetes association, those with the disease spend on average $11,744 a year on health care. A little over half of that is directly related to diabetes. Expenses include hospital stays, medications and supplies, and doctor visits. The money spent on surgery “appears to provide good value,” said Thomas Hoerger, who presented the findings last month at a meeting of health economists.