Students returning to the Pittsburgh Public Schools yesterday were hit with a quick lesson in subtraction:

Candy bars, gum and Little Debbie snacks were absent from vending machines. Sweetened ice tea was more difficult to find in the cafeteria. Food portions were smaller than they were last school year.

Annie O'Neill, Post-Gazette Beth Leo, third-grade teacher at Cardinal Wright Regional School, says the students love to jump rope. "Who would think something so simple would be so popular?" she asked. Click photo for larger image. About the series Sunday: Starting early From reading to algebra, everything in school is starting earlier   Monday: Math and reading No Child Left Behind has altered the face of education   Tuesday: Data Performance data driving education now   Wednesday: Business Education booms into an $850 billion enterprise   Thursday: Discpline Zero tolerance makes discipline more severe, involves the courts   Friday: Wellness Snacks, soft drinks banished as schools focus on nutrition   Saturday: Higher Education Lines blur between nonprofit and for-profit schools   Back to school in the region: West: New technology, teachers greet pupils North: It's a brand new year South: Pupils return to healthier food, online learning

Once again, the federal government has implemented a law likely to cause belt-tightening at the local level. Educators, nutritionists and child advocates are hoping so, anyway.

Responding to an epidemic of child obesity, Congress two years ago required school districts nationwide to have wellness policies in place by the start of the 2006-07 school year. Those policies must encourage healthier living through proper nutrition, exercise and wellness education.

In Pittsburgh, the school board got the ball rolling last school year with a ban on soda pop and fried potato chips, food service director Danny D. Seymour said.

"At first, they weren't real happy," Mr. Seymour said of hungry students.

The restrictions, based on state guidelines, got tighter for 2006-07.

Among the items now gone from vending machines or cafeteria a la carte lines are chocolate, licorice, marshmallow candy, hard candy, candy-coated popcorn, many pastry items and some cheese-and-cracker snacks. Mr. Seymour said students still will see single-serving packages of cookies, crackers and other snacks packing fewer than 200 calories.

Mr. Seymour said no more than 25 percent of the drinks sold in city schools this school year will be iced teas or fruit-based or flavored drinks. Instead, students will be offered unflavored water, 12-ounce containers of pure fruit juice and 16-ounce containers of low-fat or no-fat milk.

In 2008-09, drinks will be limited to unflavored water, 6-ounce containers of pure fruit juice and 8-ounce containers of low-fat or no-fat milk. The smaller serving sizes reflect concerns that students not only make poor food choices but consume too much overall.

The school district will be rounding out menus with healthier choices, including more whole grains, fresh fruits and vegetables and higher-fiber foods. By 2008, all foods will contain "minimal or no" trans fats, according to the district's nutrition standards.

Students across the state and nation are making similar transitions, with a mixture of grace, surprise and grudging acceptance.

"Going from white bread to wheat bread was very traumatic for a lot of students," said Sharon Fissel, director of policy services for the Pennsylvania School Boards Association.

Some policies extend to fund-raisers and classroom parties. Candy sales and birthday cupcakes are on the way out, Ms. Fissel said, but many districts are expected to keep the standard fare at concession stands.

"People can still have their pizza and soda at the ballgame," she said.

Cardinal Wright Regional School, a Catholic Diocese of Pittsburgh elementary school on the North Side, is holding a candy fund-raiser this school year. But Principal Ken Macek said no sweets will be consumed during the school day, and he held out the possibility of eliminating it down the road.

Mr. Macek's students seemed happy enough yesterday as they ate bagged lunches purchased from the Pittsburgh Public Schools. The meal consisted of a ham sandwich on what looked to be a regular bun, plus small fruit turnovers, small cartons of orange-pineapple juice and low-fat white or chocolate milk.

Third-grader Harmony Walden was well on her way to good health. She gave away the turnover and divested the sandwich of its bun.

"I don't eat the bread," she said. "I hate the bread."

Cardinal Wright traditionally has not operated a vending machine during the school day, so students can't miss what they haven't had. Mr. Macek said, however, the "old favorite, Gatorade, has gone by the wayside," no longer offered a la carte in the cafeteria.

"Our children are devastated," he said.

As the adage says: It's for their own good.

About 15.5 percent of American adolescents are obese, three times the rate in 1980. About 15.3 percent of children are obese, more than twice the level in 1980, according to the American Obesity Association.

Obesity has been linked to more than 30 medical problems, including Type 2 diabetes, coronary heart disease, birth defects, high blood pressure and various kinds of cancer, the association said.

A Rand Corp. study, published in March, showed lower test scores among girls who became overweight in kindergarten through third grade. The study found that overweight boys had more absences than peers of normal weight.

Many of Mr. Macek's students brought lunches from home, and there's no controlling the nutrition of those meals.

That's why, in line with the wellness policies, nutrition has become a more important part of a school district's curriculum. Schools also are using physical education classes to encourage individual activities like walking and jogging, sometimes at the expense of group activities like dodgeball.

Districts don't merely want to force students to eat well at school, but to encourage them to make lifelong healthy choices.

In some places, the message is sent in creative, morale-boosting ways. Pennsylvania Advocates for Nutrition and Activity lists the following "success stories" on its Web site at www.panaonline.org:

Posters on the walls at Neshaminy Middle School in Bucks County feature smiling teachers with milk mustaches, modeled on the milk industry's marketing campaign. The school put out a call for healthy recipes to be included in a cookbook, and healthy eating is touted during the daily announcements.

Bedford Area School District keeps fitness "portfolios" to encourage healthy living among middle-grade and high school students.

At the beginning and end of each school year, staff members record each student's height, weight, body mass index, blood pressure, heart rate, flexibility, number of push-ups and sit-ups completed in 60 seconds and time taken to run four laps on a track. School officials hope the record will be a motivational tool.

After math class, who wouldn't want to let off steam?

Carrie Budman, a second-grade teacher at Fishing Creek Elementary School in Cumberland County, lets her students jog around the school for five minutes after an hour of math instruction.

Some schools and districts are promoting wellness through partnerships with hospitals and nonprofit groups.

Cardinal Wright, for example, takes part in the "Walk to Win" program sponsored by Allegheny General Hospital. Teachers and other staff receive pedometers to log the steps they and students take during a 30-day period.

Pittsburgh Public Schools is cooperating in a study, funded by the National Institute of Diabetes and Digestive and Kidney Diseases, to evaluate diabetes-prevention strategies.

After a pilot program at what is now Rooney Accelerated Learning Academy on the North Side, researchers announced plans in January to expand the program to six schools. Researchers said they intend to follow a group of students from grade six through grade eight.

The federal government requires wellness policies in schools participating in the federally subsidized lunch program, and that's just about all of them.

The law doesn't affect federally subsidized meals themselves, which already meet federal nutrition standards. Instead, it has had the effect of raising nutritional standards on a la carte foods and vending machine products that school districts offer as supplements to the federal program.

Many schools incorporated longtime common-sense practices into the required wellness policies.

At Cardinal Wright, for example, students long have lined up to wash their hands before lunch.

"That's an absolute given," Mr. Macek said, as a teacher squirted soap onto each pair of hands.

Mr. Macek said teachers also are expected to lead activity on the playground.

Yesterday, two teachers helped to hold jump ropes while Harmony and other students took turns skipping. She said she's counted as high as 100 before stumbling.

Mr. Seymour said he believes snack companies will come out with more school-friendly products.

Big things have been happening at McKee Foods Corp., the Collegedale, Tenn., maker of Little Debbie and Sunbelt products.

McKee Foods spokeswoman Georgia Duke said the company recently introduced "nourishing snack bars" that offer smaller serving sizes and fewer calories than other snacks but have the taste of Little Debbie's popular Oatmeal Creme Pies, Swiss Cake Rolls and Nutty Bars. Ms. Duke wasn't immediately able to say whether the new products were related to school wellness campaigns or part of the company's regular efforts to keep Little Debbie financially fit.

"We're also coming out soon with a product called Snow Puffs," she said. It will offer a smaller-than-usual serving size, but Ms. Duke hadn't yet tasted it.