Many members of the armed forces are battling the bulge, but they may find the Internet to be a valuable weapon.

About 57 percent of all active duty military personnel are overweight or obese, compared with about 65 percent of the U.S. population, said Maj. Christine Hunter, an Air Force psychologist. She's the lead researcher on an Internet study presented this month at an Obesity Society conference in Vancouver, B.C.

Excess weight is particularly a problem in the armed services, Hunter said. "We are often deployed to austere conditions where we have to be able to handle extreme heat and strenuous physical activity. Being overweight can hamper performance," she said.

To see if the Internet could be used to facilitate weight loss, researchers with the Air Force and the Baylor College of Medicine in Houston recruited 452 Air Force personnel. They ranged from being at the top of the healthy-weight range for their height to being obese, more than 30 pounds over a healthy weight. Their average age was 34, half were men, and there was a diversity in rank.

Participants were divided into two groups. Half were assigned to a control, or baseline, group and were encouraged to pursue a weight-loss plan such as a military-sponsored program.

The other half were part of a comprehensive program that included a self-help book outlining a reduced-calorie diet, two motivational phone calls from a weight-loss professional and an interactive Internet program in which participants received weekly feedback on their food and exercise diaries. They could e-mail specific questions to weight-loss counselors.

During the study, some personnel were deployed to Iraq, Afghanistan or other places, but they continued with the program. After six months: