If you're a kid looking for a drink in one of Columbus City Schools' vending machines this year, the choice has been made for you. You're having water.

And if you're looking for a snack, there will be fewer Snickers bars and bags of Doritos than there were in previous years, plus a bright red label to remind you that those aren't the most healthful snack choices, anyway.

"You may still see Skittles, but there will be a limited amount of them," said Cori Henthorn, a nurse who supervises health and wellness efforts for the district. "And it's plain water -- no additives, no sweeteners, no carbonation. Water only."

Only 15 percent of snacks in district vending machines will be of the low-nutrient variety this school year. Thirty percent will be of the "best choice" variety -- low-fat and nutritious. During the next two years, empty-calorie snacks will be phased out and better options phased in.

These types of get-healthy steps are drastic, experts say, and not just because kids (and adults in the schools) might object. There's the potential to lose money. "This is very aggressive. You see school districts do this, but it's rare to see a poor, urban school district of this size make changes that are this dramatic," said Robert Murray, a physician and director of the Center for Healthy Weight and Nutrition at Nationwide Children's Hospital. "They know they've got a huge problem."

The district knows it will lose money from vending, which goes to individual schools principals' funds, spent mostly on student activities.

Sports drinks, juice and soda were removed from the beverage vending machines last school year because of student health concerns. The district didn't track vending revenue the year before last, spokeswoman Kim Norris said, but the water-only vending raised $56,000. Anecdotally, the district knows that it was a significant decrease, Norris said.

"We expect to see an initial dip in revenue," Henthorn said. Other districts that have restricted their beverage offerings have lost money at first but rebounded, she said.

The district started taking drastic action last year because of a study by its nurses showed a spike in the number of children with diabetes, hypertension and obesity.

Columbus students in kindergarten and third, fifth, seventh and ninth grades undergo health screenings now; about 30,000 were screened last school year. About 53,000 students are enrolled in the district. "Even in the younger grades, you'll find about 40 percent of those kids are overweight. Out of that 40 percent, the vast majority are obese. They're not chubby, they're obese," Murray said.

National studies show kids are becoming increasingly overweight and obese. In the late 1970s, 6.5 percent of children between ages 6 and 11 were obese; by 2006, 17 percent of American kids were, according to surveys from the Center for Disease Control and Prevention in Atlanta.

The snack rating system the district has adopted is called the Snackwise Nutrition Rating System. It was developed by experts at Children's Hospital and rates snacks based on their calories, fat, saturated fat, protein, fiber, sugar and vitamin and nutrient content. Some school districts in Ohio already are using the system, including Westerville and Olentangy in central Ohio.

Columbus schools also have been trying an after-school fitness club designed primarily for overweight students. It was created at Children's Hospital, too. The F.A.N. (fitness and nutrition) clubs at Livingston and Lincoln Park elementaries have about 30 students each. Organizers wanted to expand to seven more schools this year but don't have the roughly $105,000, or $15,000 per new location, it would cost. The goal is to eventually have clubs in 20 district schools.

Doug Wolf, who coordinates the community health initiative at the hospital and is an athletic trainer in sports medicine there, said the schools find club members both through the nurses' screening process and through a simple sign-up option. While the club wants to get overweight kids to join, it asks everyone in third, fourth and fifth grades if they'd like to sign up. "It's promoted as learning to be active and learning to be healthy. By not declining kids who are not in the overweight category, there's no stigma being attached to the program," Wolf said.

Club members spend 90 minutes after school -- a few times a week for 30 weeks -- learning about healthy lifestyles and proper ways to exercise, then working out by playing games. Students who participated last year increased the number of sit-ups and push-ups they could do and increased their aerobic endurance by more than 40 percent, according to the hospital's research.