Part of the law sets nutritional standards for meals and minimum levels of physical education. It also expands breakfast and supper programs, and includes other aspects of wellness in schools -- P.E. can't be used as punishment, schools are encouraged to serve vegetarian options and students must have access to cold, filtered water.
It's snack time at Powell Elementary School in Northwest D.C. Students can pick any one fruit and one vegetable from a platter that includes red peppers, orange cantaloupe and green sugar snap peas. Different colors can help entice children to try something new. Some of them have never seen foods such as strawberries or squash. Nine-year-old Steven Alvarez tastes grapefruit for the first time.
"It's my new favorite fruit," he exclaims. "My friends, they don't try it 'cause it looks gross. They only like things they have tried before."
Children learn about how eating healthy can improve their memory and build strong bones. But 7-year-old Devisha Hockaday had an entirely different reason when she chose carrots. She says when one of her aunts was young, she was told that eating carrots would make her eyes "look beautiful."
"And when she [grew] up, they did."
The Healthy Schools Act was seen as a way to reach more than 70,000 students in the public school system. And Ed Bruske, a blogger who has written extensively about D.C.'s school, meals says change was sorely needed.
"Kids were getting 15-16 teaspoons worth of sugar in breakfast," says Bruske. "One lunch consisted of a bag of Sun Chips, potato wedges and strawberry milk. That qualified as a lunch in D.C. schools."
Jeff Mills heads food and nutrition programs for DCPS. He's responsible for 60,000 meals served everyday at more than 120 schools. Mills says students are now served more whole grains, low- or non-fat milk and a different fruit and vegetable each day.
"No flavored milk," says Mills. "No fried food on the menu at all. We don't have any chicken nuggets, no French fries."
The District is one of the few cities in the country to fund the changes. One way it supports the initiative is through a soda tax, which generates $6 million for the Healthy Schools Act.
While Bruske calls the changes "dramatic," he says the nutritional standards don't go far enough. He wants to see less sugar, fewer potatoes and less salt. He also wants to see much more emphasis on educating children about what they're being served and why.
"One of the students asked if they could grow McNuggets."
"It's not a kid-friendly program," says Bruske. "It's a government program with standards that are designed by a committee and rules and regulations that are aimed at adults, and the kids are the caboose. They're the last consideration, you know –- will they eat this food?"
Mills agrees getting children to eat the healthy food is challenging. He says baked fish was an unexpected hit, so were fresh salads and barbecued chicken. But not every dish was a success. Mills says the "Rockin' Morrocan" stew was a disaster.
"We're challenged with adding more beans and lentils to the menu, but the feedback we got early on was anything with beans the kids didn't like," he says, laughing as he recalls the bean-heavy Morrocan dish.
Mills says implementing the law wasn't just about changing the menu. He explains that a lot of work went on behind the scenes, including more staff training.
The menu changes required more education on how to handle and store food properly.
"Needing to convert freezers to refrigerators because we have much less frozen food than we've ever had before," he says. "And we have more deliveries now because we have more fresh produce coming in."
Mills plans to expand the number of salad bars in schools and buy more foods from local farmers. The law also encourages school gardens, an initiative D.C. Council member Mary Cheh insisted on after she watched a teacher talk to her class about growing food.
"One of the students asked if they could grow McNuggets," says Cheh.
She expects the rates of obese children will decrease over time. But revamping the standards is what she calls "independently valuable."
Sarah Lee is a health scientist with the Centers for Disease Control and Prevention. She says when children eat breakfast they do better in school. But there just isn't enough research to show a connection between the quality of food and academic ability. However, Lee says the link between exercise and school work is much stronger.
"Don't be afraid to add more physical activity to the school day," she says. "It doesn't take away from academic performance. In fact, in many cases, it enhances it."
Another piece of the Healthy Schools Act makes exercise mandatory. A dozen seventh-graders at Brookland Education Campus in Northeast D.C. line up at one end of their small gym. They're listening to instructions from an iPod.
"The running speed starts slowly but gets faster each minute after you hear this signal," instructs a voice on the iPod.
It's part of a physical education program recently introduced into every DCPS school. Students begin running. If they get tired, they can stop and sit down.
Their coach, Chris Grier, says it's a move away from a universal standard toward measuring improvement for each child. Grier was 300 pounds as a teenager, and he remembers how much he dreaded the "one-mile run" and the "pinch test."
"When they took our body fat percentage they would pinch our skin with a little plastic thing on the back of our arm or abdomen and combine these measurements to come up with a percentage," he says. "Being someone who grew up obese I dreaded that."
Grier says DCPS has invested in electronic fat monitors. And schools are adding a variety of activities for students, everything from Tai Bo and yoga to archery and field hockey. All the high schools now have giant computer screens with exercise programs.
At the end of the class, Grier talks to Tyreece Huff. He beat his previous score.
"You did excellent," Grier says to Tyreece. "You did 21 laps more than before on the running test, so that's 98 total laps."
And even though it's not the point, Tyreece says he loves competition.
"It's adrenalin inside of you saying, come on this is you," says Tyreece. "This is your score and that's the other guy's score, and you have to beat them."
Students' measurements and progress are tracked in a database. The goal is to be able to see whether overtime students system-wide are losing weight. But there are challenges.
Physical education is not funded in the Healthy Schools Act. A federal grant of $1.5 million paying for the equipment being used now runs out next year. And in 2014, the law requires five times the amount of physical activity for middle school students compared to today.
For now, however, school officials say they are working hard to motivate children most at risk.
"I show them pictures of when I was a kid," says Grier. "They can't even believe it's me. I say 'Listen I've been there and you can do it.'"
While it's too early to measure whether the Healthy Schools Act is making a difference, educators say sometimes just believing it's possible to lose weight is half the battle.
This is part four of a five-part series on childhood obesity in America from WAMU 88.5 News.