For Jorge Collazo, executive chef for the New York City public schools, coming up with the perfect jerk sauce is yet another step toward making the 1.1 million schoolkids he serves healthier. In a little more than a year, he's introduced salad bars and replaced whole milk with skim. Beef patties are now served on whole-wheat buns. Until recently, "every piece of chicken the manufacturers sent us was either breaded or covered in a glaze," says Collazo. Brandishing the might of his $125 million annual food budget, he switched to plain cutlets and asked suppliers to come up with something healthy--and appealing--to put on top. Collazo tastes the latest offering. The jerk sauce isn't overly processed and doesn't have trans fats. "Too salty," he says with a grimace. Within minutes, the supplier is hard at work on a lower-sodium version.

A cramped public-school test kitchen might seem an unlikely outpost for a food revolution. But Collazo and scores of others across the country--celebrity chefs and lunch ladies, district superintendents and politicians--say they're determined to improve what kids eat in school. Nearly everyone agrees something must be done. Most school cafeterias are staffed by poorly trained, badly equipped workers who churn out 4.8 billion hot lunches a year. Often the meals, produced for about $1 each, consist of breaded meat patties, french fries and overcooked vegetables. So the kids buy muffins, cookies and ice cream instead--or they feast on fast food from McDonald's, Pizza Hut and Taco Bell, which is available in more than half the schools in the nation. Vending machines packed with sodas and candy line the hallways. "We're killing our kids" with the food we serve, says Texas Education Commissioner Susan Combs.

As rates of childhood obesity and diabetes skyrocket, public-health officials say schools need to change the way kids eat. It won't be easy. Some kids and their parents don't know better. Home cooking is becoming a forgotten art. And fast-food companies now spend $3 billion a year on television ads aimed at children. Along with reading and writing, schools need to teach kids what to eat to stay healthy, says culinary innovator Alice Waters, who is introducing gardening and fresh produce to 16 schools in California. It's a golden opportunity, she says, "to affect the way children eat for the rest of their lives." Last year star English chef Jamie Oliver took over a school cafeteria in a working-class suburb of London. A documentary about his work shamed the British government into spending $500 million to revamp the nation's school-food program. Oliver says it's the United States' turn now. "If you can put a man on the moon," he says, "you can give kids the food they need to make them lighter, fitter and live longer."

Changing school food takes time. More than a decade ago, when local restaurateur Lynn Walters lobbied school-board members in Santa Fe, N.M., to provide kids with --healthy alternatives to soggy pizza, they refused. So Walters and parent volunteers began an in-school cooking class. Armed with an electric griddle and a bag of fresh produce, they taught fractions using measuring cups and discussed nutrition over bunches of kale while concocting such lunch alternatives as spinach fettuccine and black-bean tostadas. The teachers loved it; so did the kids. But getting the entrees on the school menu was another challenge. The school kitchens there, like many around the country, were equipped to reheat food, not to prepare it. "I was passionate, but I was ignorant of the realities" the school was facing, says Walters, who got a grant to buy knives so the school cooks could at least peel and chop fresh fruits and vegetables.

Changing school food will take money, too. Many schools administrators are hooked on the easy cash--up to $75,000 annually--that soda and candy vending machines can bring in. Three years ago Gary Hirshberg of Concord, N.H., was appalled when his 13-year-old son described his daytime meal--pizza, chocolate milk and a package of Skittles. "I wasn't aware Skittles was a food group," says Hirshberg, CEO of Stonyfield Farm, a yogurt company. So he devised a vending machine that stocks healthy snacks: yogurt smoothies, fruit leathers and whole-wheat pretzels. So far 41 schools in California, Illinois and Washington are using his machines--and a thousand more have requested them. The schools don't make as much money. Kids spend about half as much on granola bars as they did on Fritos. But, Hirshberg says, "schools have to make good food a priority."

Some states are trying. California, New York and Texas have passed new laws that limit junk food sold on school grounds. Districts in California, New Mexico and Washington have begun buying produce from local farms. Las Vegas parent Terri Jannison says real change can be incremental. After three years of lobbying, the cafeterias there now sell reduced-fat muffins. The soda and candy in the vending machines have been replaced by juice and beef jerky. Doritos were banned, but then replaced by baked Doritos. "It's not perfect," says Jannison. But it's a cause worth fighting for. Even if she has to battle one chip at a time.