Junk food advertising in schools will be limited by a new regulation from the U.S. Department of Agriculture.

The proposed guidelines make sure that schools participating in the national school lunch program only allow marketing of foods to kids that are consistent with the recently-released Smart Snacks in School standards, according to a news release from the USDA. The proposal, which has a 60-day comment period that ends in late April, also would require that schools make their wellness policies available for public review.

First lady Michelle Obama and Agriculture Secretary Tom Vilsack announced the school wellness standards on Feb. 25. School wellness policies have been required for schools participating in the lunch program since 2006, but the proposed regulation adds language on appropriate marketing messages.

“The idea here is simple — our classrooms should be healthy places where kids aren’t bombarded with ads for junk food,” first lady Michelle Obama said in a news release. “Because when parents are working hard to teach their kids healthy habits at home, their work shouldn’t be undone by unhealthy messages at school.”

Vilsack said the new local wellness standards support better health for kids.

The National Harbor, Md.-based School Nutrition Association, representing 55,000 school nutrition professionals, said in a statement that the proposed rule appears to be a positive step.

“Supporting nutrition education and physical fitness while limiting marketing of unhealthy foods will help reinforce positive messages in and out of the cafeteria, Leah Schmidt, president of the association, said in the statement. “School nutrition professionals have been working hard to offer more fruits, vegetables and whole grains with school meals and to make those healthy choices more appealing to students.”

Tracy Fox, president of Food, Nutrition & Policy Consultants LLC, attended the White House event announcing the proposed guidelines and said they will be a good complement to the USDA rule on food sold in schools, known as the Smart Snacks regulation.

“In its simplest terms, schools won’t be able to market foods that don’t comply with the new Smart Snacks (rules),” she said.

For example, Coke couldn’t be sold in vending machines, but Coca-Cola’s lower-calorie options could be in the machines.

“It is aligning the marketing environment to what is now going required to be sold beginning next fall,” she said.

Fox said the biggest challenge may be assigning responsibility at the local level to make sure the regulations is implemented correctly. Many nutrition personnel at schools may already feel hard-pressed to meet new nutrition guidelines.

“It will just be a matter of how to manage that and administer it,” she said.

The USDA has launched a new website to help schools implement school wellness policies, according to the release.

The agency also announced that, beginning July 1, more than 22,000 schools across the country — which serve primarily low-income students — will be eligible to serve healthy free lunches and breakfasts to all students. The agency said in the release that will help as many as 9 million children eat healthy meals at school, according to the release. More information about the program is available online.