WASHINGTON — Don’t touch my brownies!

A child nutrition bill on its way to President Barack Obama — and championed by the first lady — gives the government power to limit school bake sales and other fundraisers that health advocates say sometimes replace wholesome meals in the lunchroom.

Republicans, notably Sarah Palin, and public school organizations decry the bill as an unnecessary intrusion on a common practice often used to raise money.

“This could be a real train wreck for school districts,” Lucy Gettman of the National School Boards Association said Friday, a day after the House cleared the bill. “The federal government should not be in the business of regulating this kind of activity at the local level.”

The legislation, part of first lady Michelle Obama’s campaign to stem childhood obesity, provides more meals at school for needy children, including dinner, and directs the Agriculture Department to write guidelines to make those meals healthier. The legislation would apply to all foods sold in schools during regular class hours, including in the cafeteria line, vending machines and at fundraisers.

It wouldn’t apply to after-hours events or concession stands at sports events.

Margo Wootan of the Center for Science in the Public Interest says the bill is aimed at curbing daily or weekly bake sales or pizza fundraisers that become a regular part of kids’ lunchtime routines. She says selling junk food can easily be substituted with nonfood fundraisers.

“These fundraisers are happening all the time,” Wootan said. “It’s a pizza sale one day, doughnuts the next... It’s endless. This is really about supporting parental choice. Most parents don’t want their kids to use their lunch money to buy junk food. They expect they’ll use their lunch money to buy a balanced school meal.”

Palin mocked the efforts last month by bringing a plate of cookies to a school speech in Pennsylvania. Rep. John Kline of Minnesota, the senior Republican on the House Education and Labor Committee, said the federal government “has really gone too far” when it is deciding when to hold bake sales.