There's no muscle-bound instructor snarling for another pull-up or large cash prize offered to the person who sheds the most pounds.

Even so, about 35,000 Rhode Islanders have competed over the last four years in their own, quieter variation of "The Biggest Loser," joining a statewide weight loss and fitness challenge founded by a Brown University medical student.

Now Shape Up Rhode Island has received a $105,000 national health care prize that program creator Rajiv Kumar says will help make it more accessible to low-income residents who may be turned off by the $20-per-person entrance fee.

Kumar, 26, founded the program in 2005 when he was a medical student, struck by how many ailments _ like high blood pressure and certain types of diabetes _ could often be controlled or even prevented by patients. Even though doctors give sound advice on how to get healthy, Kumar said, patients often lack the support or routine to change their behavior.

"It was interesting and exciting to me as a medical student to think that we could actually prevent these diseases before they happen and reduce the human and economic toll that we bear along with them," said Kumar, a third-year student who plans to focus on preventive medicine.

His answer was Shape Up RI, which uses competition and old-fashioned peer pressure as motivation, encouraging people to not only lose weight but also adopt healthy habits.

Colleagues, friends or family members sign up in teams of up to 11, with employers often paying the entrance fee. Teams with pedometers and log books compete over 12 weeks in up to three categories: average weight loss, exercise minutes and number of steps taken. The competition is supplemented by seminars on nutrition and other health-related topics.

The teams record their progress every two weeks, and because there's no money or other award for the winners, there's little incentive to lie.

"People just compete for bragging rights and self-esteem and the benefits of improving their health," Kumar said.

Participants say the structure keeps them accountable since even one slacker can hurt the team's overall results.

"Working with people on your team, they say, 'OK, I know you're busy today, but you've got to go out and walk and meet that goal,'" said Leo Perrone, a three-year participant who tries to walk with colleagues 10,000 steps a day _ or about five miles.

Perrone, director of benefits for the gaming technology company GTech, says his weight has been stable, but he credits the program with lowering his blood pressure.

Melissa Farizer, 44, participated in a condensed version of the program last summer with seven colleagues at Herff Jones, a supplier of class rings and caps and gowns. A fast-food devotee and borderline diabetic who weighed 260 pounds when she started, she says she lost 35 pounds, though she later gained five pounds back.

She attended line dance events two nights a week and joined her team on weekend walks around Roger Williams Park in Providence. As team leader, she would prod frustrated teammates to stay motivated, but also leaned on their support to temper her junk food cravings. Continued...