Pizza still counts as a vegetable in U.S. public school cafeterias.

The U.S. Agriculture Department originally wanted to require a half cup of tomato paste for a pizza slice to qualify as a vegetable. But on Thursday, the U.S. House of Representatives backed off from the stricter requirement. A child nutrition law bill in the U.S. called on schools to improve the nutritional quality of lunches. Charles Rex Arbogast/Associated Press

A slice of pizza will continue to qualify as a vegetable because it contains two tablespoons of tomato paste.

"It's an important victory," Corey Henry, spokesman for the American Frozen Food Institute (AFFI), told Reuters.

The trade association lobbied Congress on behalf of frozen pizza sellers, such as ConAgra Foods Inc and Schwan Food Co and french fry maker McCain Foods Ltd.

The USDA also proposed limits on french fries, increasing the variety of fruits and vegetables and limiting starchy vegetables including corn and green peas.

Earlier this week, the U.S. Center for Science in the Public Interest said the legislation would be a bigger "blunder" than when U.S. President Ronald Reagan's administration tried and failed to credit ketchup as a vegetable in the school lunch program.

"Pizza should be served with a vegetable, not count as one," the consumer advocacy groups said on its website.

The decision comes as Michelle Obama continues her campaign to combat childhood obesity.