WARWICK — Aimee Berling suffers from blood clots in her lower legs. Ken Stafford is diabetic. Because of their health conditions, the Cranston residents must keep active and watch their diets.

That need to exercise and eat healthy brought Berling and Stafford out yesterday morning to the kickoff of Shape Up RI, an annual statewide health campaign that encourages Rhode Islanders to improve their health and lifestyle by increasing their levels of physical activity and adopting healthful eating habits.

The two are on a team with a group of friends called the “Fat Cats.”

“My doctor wants me to walk more, but it hurts to walk. I have to endure the pain to get healthier. It’s a Catch-22,” said Berling, an electrical contractor who has endured leg problems for four years. “I need that motivation from friends to do it.”

Though the competition doesn’t officially start until tomorrow’s weigh-in, a few hundred participants gathered at the Community College of Rhode Island, running through some quick stretches and getting necessary supplies, including pedometers to monitor walking distance and the event’s aqua wristbands.

Founded in 2005 by Rajiv Kumar, a second-year medical student at Brown University, Shape Up RI takes teams through four months of competition in three categories: losing the most weight, taking the most steps (as measured by pedometers given to each team member), and most exercise hours logged.

Teams of 5 to 11 people keep their personal exercise and weight logs, submitting them every two weeks to their team leaders. Many teams do physical activities together, such as playing in a volleyball league or walking in a road race two things the 11-member Banneker Industries team was doing this year, said team member Roberta Ramos, of East Providence.

The competition, which concludes May 20, can be tracked on the program’s Web site, www.shapeupri.org. Last year, 205 teams — nearly 1,800 competitors lost a combined 5,911 pounds, a 5.86-percent weight loss, and logged 69,132 hours of physical activity.

Top teams this year will get to play a softball game at McCoy Stadium, in Pawtucket, and the first-place team will get a tour of Boston’s Fenway Park and tickets to a game, according to Sam Horn, a former Red Sox player (now a motivational speaker) who was the keynote speaker at yesterday afternoon’s event

The idea of Shape Up RI grew from Kumar’s frustration about how ineffectively people were attacking their health problems. He was troubled by national health trends; two-thirds of Americans are overweight or obese.

Obesity and the chronic health problems it causes are becoming so prevalent that the new generation of Americans stands to have a shorter life span than their parents, Kumar said. In Rhode Island, 56 percent of the population is overweight or obese, the Centers for Disease Control and Prevention reported in 2004.

“Weight loss is such a personal issue. Most of us go at it alone,” Kumar said. “But the problem is that there is no one there to motivate us when it gets hard, to keep us going in the battle.”

To push back the tide of obesity, Kumar said Americans must undergo a dramatic lifestyle change, learning healthier ways to eat and incorporating more daily physical activity. Preventing or controlling obesity doesn’t require extreme dieting, but making modest and attainable improvements in activity and food choices.

Setting team and personal goals and the competitive environment of the event push participants to work harder than they otherwise would on their own, said East Greenwich resident Adriana Gomez, who is on Butler Hospital’s team.

In the event’s second year, more than 6,000 people have paid the $15 registration fee to enter the competition, up from 1,738 last year.

Much of that growth is due to support from employers looking to improve the health of their workers in the face of soaring health insurance prices, Kumar said.

Forty companies and organizations paid to register their employees in the competition, including event sponsor Blue Cross & Blue Shield of Rhode Island, which enrolled half its employees.

Kumar said he hopes that “exciting trend” continues next year, as he pushes for health insurance companies to foot the registration fee for their subscribers.

pmarcelo@projo.com