WASHINGTON (AP) — House Republicans are siding with food companies resisting the Obama administration's efforts to pressure them to stop advertising junk food for children.

Some food companies say the government is going too far with guidelines proposed earlier this year by several government agencies. The voluntary guidelines would attempt to shield children from ads for sugary and fatty foods — think colorful characters on cereal boxes — on television, in stores and on the Internet. Companies would be urged to market foods to children ages 2 through 17 only if they contain specific healthy ingredients and are low in fats, sugars and sodium.

Even though the guidelines are voluntary, many companies are aggressively lobbying against them, saying they fear the government will retaliate against them if they don't go along.

Republicans are attempting to delay the guidelines by including a provision in next year's Federal Trade Commission budget that would require the government to study the potential costs and impacts of the guidelines before implementing them.

As food companies have protested, criticism has ramped up on Capitol Hill. Missouri Rep. Jo Ann Emerson, the Republican who sponsored the provision, says she is concerned that the voluntary rules "would lead to extraordinary pressure from the federal government."

Other Republicans have called the rules overreach, saying they encompass too many foods. The standards are meant to crack down on ads for the unhealthiest foods, but others are caught in the crossfire. Advertising for some whole wheat breads would be restricted because they have too much sodium, for example, and bottled water could be targeted because it doesn't include enough nutrients.

Rep. Jack Kingston, R-Ga., a supporter of Emerson's effort, said the guidelines are "basing decisions on emotions and not facts."

Some Democrats have shown concern with the voluntary rules, as well. Rep. G. K. Butterfield of North Carolina, in a letter to the government agencies in charge of the effort, said the government "has produced no evidence that I am aware of that the proposed restrictions will serve the government's goals of changing long-term eating habits."

The spending bill that includes the delay cleared the House Appropriations Committee last month. It could come before the full House as early as next week.

Food companies argue that the rules are back-door regulations that could trample their First Amendment rights of free speech. Scott Faber, a lobbyist for the Grocery Manufacturers Association, which represents the nation's largest food companies, says his group estimates the standards would affect marketing of almost all of the nation's favorite foods.

"What is very troubling about the administration's proposal is that they would have us drastically change food marketing without presenting any evidence that it changes diets or assessing the costs," Faber said.

Health advocates disagree.

"The industry is exaggerating the influence of these voluntary regulations to gin up opposition," said Margo Wootan of the Center for Science in the Public Interest. "These standards are supposed to provide a model of how self-regulation can work."

While opponents of the guidelines are using examples of healthy foods that would be covered to make their point, Wootan points out that advertising for many foods would be allowed — including children's chicken nuggets meals from McDonald's and Burger King and cereals such as Frosted Mini Wheats and Honey Bunches of Oats.

As criticism has become louder, the Federal Trade Commission — which developed the voluntary regulations with the Agriculture Department, the Food and Drug Administration and the Centers for Disease Control — has tried to debunk what it says are myths about the standards.

In a posting on the FTC Web site, David Vladeck, director of the FTC's Bureau of Consumer Protection, says there are no legal consequences for companies that don't follow the rules.

"Nobody's saying Toucan Sam has to fly the coop," Vladeck said. "Ideally, during the next five years it would be great to see the cereal companies voluntarily tweak their formulations to raise the whole grain content and lower the added sugars for cereals marketed to children."

Vladeck also addressed the issue of government overreach.

"The proposal is designed to support — not supplant — moms and dads," he wrote.