When insulin was discovered in the early 1920s, some doctors and patients jubilantly proclaimed it a cure. But as we now know, while insulin is an extraordinarily good treatment, it by no means eliminates diabetes.

Today, after some promising, much-touted results from a new study, rumors are once again circulating of a “cure,” this time for type 2: weight-loss surgery.

The “cure” in question is laparoscopic adjustable gastric banding, or lap-banding. Unlike the more invasive gastric bypass surgery, a physical restructuring of the digestive tract, in lap-banding surgeons fit an inflatable belt around the top of the stomach to shrink it. The result? Patients feel fuller faster, and lose weight.

In the study, researchers looked at 60 patients with recently diagnosed type 2 diabetes and a body mass index (BMI) between 30 and 40 (higher than 30 is considered obese). Half of them had lap-banding surgery, while the others participated in a more conventional weight-loss program. Remarkably, three-quarters of lap-banded patients eventually normalized their blood glucose levels without needing diabetes medications, compared with just over 10 percent of those pursuing nonsurgical weight loss.

“We’re not calling it a cure,” says lead author John Dixon, MBBS, PhD, of the Alfred Hospital in Melbourne, Australia. “We would prefer to call it remission…there is a high risk for redeveloping diabetes.” But, he notes that soon after surgery most patients “don’t have signs of diabetes, and they love it.”

However, says Dixon, what’s been lost in many news reports is that it’s the weight loss after surgery, not the surgery itself, that’s the critical factor in this study, published in the Jan. 23, 2008, issue of the Journal of the American Medical Association. Still, there’s little doubt that the surgery’s shrinking of the stomach does seem to expedite weight loss: Over the course of the two-year study, the surgical group lost about 20 percent of their body mass, on average, compared with a 2 percent loss in the group using such nonsurgical means as pharmaceutical agents, increased exercise, and improved diet.

Of course, there are myriad ways to lose weight nonsurgically, with highly varied track records, points out Bret Goodpaster, PhD, an assistant professor at the University of Pittsburgh, and the nonsurgical methods in this study may not have been the most effective. Goodpaster is testing a different nonsurgical weight-loss program, and his patients “are losing substantially more than what is cited in [Dixon’s] study” for the nonsurgical group, he says.

More research needs to be done to determine whether the surgery would be beneficial for people outside the 30 to 40 BMI range, observers say. Timing of the surgery should also be considered when determining candidacy. In this case, study participants were required to have received their diabetes diagnosis less than two years before the study began.

“The surgery doesn’t work as well if people have had diabetes a long time,” says Dixon, because a long period of insulin resistance wears down the pancreatic beta cells that supply compensatory insulin.

On a more hopeful front, though, some research suggests that gastric bypass surgery may actually stimulate beta cells, and thereby promote diabetic remission even after diabetes has progressed to the point of beta cell decline.

Researchers are just beginning to understand the potential surgery-assisted weight loss has in the fight against diabetes. However, it is still unclear which surgery is best, what post-surgery weight maintenance is needed, and how long a patient can expect remission to last. Additionally, weight-loss surgery is expensive. As with insulin therapy today, in time weight-loss surgery may become accepted as another useful tool in the diabetes arsenal.