HARTFORD, Conn. | Imagine having a smaller stomach that gets fuller quicker because it's only 15 percent of its original size. If it sounds like an extreme dieting technique for models, it's not.

It's a major surgical procedure that's starting to gain acceptance as a way to treat obesity and the nation's growing number of people with diabetes.

Two of the nation's largest health insurers - Aetna and UnitedHealthcare - recently agreed to cover the $16,000 to $25,000 procedure, called a laparoscopic sleeve gastrectomy. Other insurers such as CIGNA Corp. and Anthem Blue Cross & Blue Shield in Connecticut maintain that it is still an experimental surgery that hasn't proved to be safe or effective.

The sleeve gastrectomy doesn't use a sleeve; it gets its name from the shape the stomach assumes after it's slimmed down by removing the outer curve. Instead of a kidney-bean shape, the stomach looks like a shirt sleeve.

Making the stomach into a sleeve is an alternative to more common diet-controlling surgeries such as gastric bypass and gastric banding. It's better in some ways than gastric bypass because food doesn't skip past part of the small intestine that absorbs nutrients the body needs, said John Baker, a surgeon in Little Rock, Ark., who is president of the American Society for Metabolic and Bariatric Surgery.

"It is important to provide coverage and access to a wide range of proven treatment methods," Baker said. "Sleeve gastrectomy has now reached that threshold where the data and our experience with the procedure supports its safe and effective use in people affected by the chronic disease of morbid obesity."

Baker also says the sleeve surgery will pay for itself in as little as two years, compared to treating obesity-related ailments.

Some insurers aren't so sure. For example, when CIGNA Corp. updated its coverage policy for bariatric surgery last year, the sleeve procedure was not included by the time the policy took effect on June 15, 2009.

The company's annual policy will be updated in May, and sleeve surgery will be reviewed again.