WASHINGTON (AP) — Pizzas and hamburgers in the school lunch line would be healthier under child nutrition legislation passed by the Senate Thursday, a key part of first lady Michelle Obama’s campaign to end childhood obesity.

The $4.5 billion legislation passed by voice vote would create new standards for all foods in schools, including vending machine items, to give students healthier meal options. It would also expand the number of low-income children eligible for free or reduced cost meals.

The legislation had stalled since Senate committee passage in March, but it gained new attention as the White House became involved this week. President Barack Obama on Thursday called Sen. Tom Coburn, R-Okla., who had concerns about the cost of the bill and had threatened to object to it, to assure him the legislation was paid for. The bill has been a top priority for Senate Agriculture Chairwoman Blanche Lincoln, an Arkansas Democrat who is in a tough re-election race this year.

First lady Michelle Obama praised the bill shortly after it was passed, calling it a “groundbreaking piece of legislation that will help us provide healthier school meals to children across America” that “will play an integral role in our efforts to combat childhood obesity.”

A similar bill is pending in the House after committee approval last month.

The new nutrition standards would not remove popular foods like pizzas from schools completely, but would make them healthier, using whole-wheat crust or low-fat mozzarella, for example. Vending machines could be stocked with less candy and fewer high-calorie sodas.

Creation of new standards, which public health advocates have sought for a decade, has unprecedented support from many of the nation’s largest food and beverage companies. The two sides came together on the issue as a heightened interest in nutrition made it more difficult for the companies to push junk foods in schools.

Congressional passage of the bill would be only the first step. Decisions on what kinds of foods will be sold — and what ingredients may be limited — would be left up to the Agriculture Department.

Part of the deal to move the legislation this week was to change the way it was paid for. While the committee bill partially paid for the legislation by reducing conservation subsidies paid to farmers for using environmentally friendly farming practices, the Senate-passed bill took $2.2 billion out of future funding for food stamp programs instead after some farm-state senators objected to using the subsidy money.

Hunger advocates who had previously supported the bill said they would now oppose it.

“If the only way they can pay for anything is to cut food stamp benefits, then the nation is in worse shape than we thought,” Jim Weill, president of the Food Research and Action Center, said after the vote Thursday.

Lincoln said Democrats used the money for child nutrition because lawmakers had been eyeing that pot of money for other priorities as well. Food stamp money was also used to pay for a jobs bill the Senate passed Thursday.

“I think it’s most appropriate if these dollars are going to be spent, that they are spent on nutrition for kids,” she said.

Copyright 2010 The Associated Press.