School cafeteria meals like low-fat pizzas with whole grain crust don't taste too bad to Paola Villatoro, a 17-year-old at Downtown Magnet High School in Los Angeles.

Some of it is pretty good, she said.

But West Adams Preparatory School student Alfredo Segura doesn't like them. It tastes like prison food, said Segura, 16, as he and other students ate snacks at a fast-food joint near the school.

Los Angeles Unified School District is an anti-junk-food pioneer, but the obstacles it faces show how difficult it is to change habits shaped by decades of unhealthy eating promoted by the mammoth fast-food industry.

The district's food services department has thrown out deep-fat fryolators, added more fresh foods and reduced sodium in cafeteria meals. It also has outlawed sugary sodas and banished junk food vending machines on campus.

But enforcement has been spotty and fast-food chains and convenience stores wait outside school gates, eager to provide students with a fix.

Even though she likes some of the school meals, Villatoro joins friends for weekly lunches at a fast-food outlet across from the school.

The number of U.S. fast-food restaurants exploded to about 220,000 in 2001 from 30,000 in 1970. And over the last three decades, spending on fast food hit $110 billion from $6 billion, according the public-health focused nonprofit Trust for America's Health and the Robert Wood Johnson Foundation.

As working parents turned to restaurants for cheap super-sized meals, the eating habits of adults and children alike changed and waistbands expanded.

At the same time, schools dropped recess and physical education classes that used to burn off calories, to carve out more time for lessons.

Obesity rates for school-age children have tripled to 17 percent since 1980. At that rate, there is an epidemic in the United States, according to the U.S. Centers for Disease Control and Prevention.

Experts worry about soaring rates of diabetes, heart disease and other chronic conditions as these children grow up, further adding to the country's health crisis.

In Los Angeles County 23 percent of school children were obese and another 19 percent were overweight in 2007, the county's health department said.

OUTDATED NUTRITIONAL STANDARDS

The U.S. government spends about $11.7 billion a year on school programs that provide lunch for over 30 million children and breakfast for more than 10 million -- but has not updated nutritional standards and meal requirements since 1995.

States have tried to act without waiting for the federal government. As of last August, 18 states had adopted tougher nutritional standards than the U.S. government -- but most lack enforcement power and cannot punish noncompliance, says the Trust for America's Health, a nonprofit organization that works to raise community health standards.

Recent data suggests that childhood obesity rates may be leveling off. Some experts say programs like healthier school lunches are starting to work, but others are skeptical.

President Barack Obama wants to increase funding for U.S. child nutrition programs by $1 billion per year to prevent children from going hungry in a recession that has sent unemployment to a 25-year high.

We're hoping it comes our way, said Laura Benavidez, deputy director of the Food Services Department for the Los Angeles school district with 690,000 students.

Its food services budget of $325 million this year covers not only meals, but also staff salaries, benefits, insurance utilities and utensils. It spends about 70 cents per meal, excluding milk, which costs 18 to 20 cents per serving. The district currently loses money on every lunch it serves.

At Castelar Elementary in Los Angeles' Chinatown section recently, students rushed a salad bar, scooping up orange slices and half bananas, green peas and salad -- a fair portion of which actually went into stomachs instead of trash cans.

Still, the healthy message is often undermined by school fund-raising events where selling junk food raises money for sports teams or academic clubs.

We can't undo a lot of habits, said Dennis Barrett, who oversees the district's food services operations.

In the battle between veggies and burgers, burgers may be hard to beat.

(With additional reporting by Chuck Abbott in Washington, editing by Alan Elsner)

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