MARGARET WARNER: Finally tonight: new rules requiring healthier snacks to be sold in schools beginning next year.Ray Suarez has the story.

RAY SUAREZ: Estimates suggest that many kids consume at least half their daily calories while at school. The new rules, from the U.S. Department of Agriculture, are designed to lower the amount of fat, salt and sugar in a child's diet.

Starting next summer, vending machines would not have traditional candy bars or full-fat cookies, for example. High schoolers will only be able to purchase drinks on campus that have fewer than 60 calories in a 12-ounce serving, much less than many sodas.

The regulations, which affect 50 million students, do not cover food sold after school or brought from home or at a fund-raiser.

For more, I am joined by Margo Wootan, director of nutrition policy at the Center for Science in the Public Interest.
WATCH: Seven Foods You Think Are Healthy But Aren't
WATCH: Seven Foods You Think Are Healthy But Aren't

We invited several food and beverage companies, as well as their trade associations, to join us, but they declined our offer.

Margo Wootan, how does the federal government, by what authority do they reach out into all these thousands of school districts and compel this kind of new standard?

MARGO WOOTAN, Director of Nutrition Policy, Center for Science in the Public Interest: You know, school foods is a little different than other aspects of education.

You know, often, education is more regulated at the state and local level, but when it comes to school foods, it's for a long time been a federal program. Most of the money comes from the federal government, from Congress and the U.S. Department of Agriculture. And so they have nutrition standards as conditions for getting that funding.

If you're going to take this $13 billion dollars a year, you need to serve kids healthy food. And so Congress and USDA sets detailed nutrition standards for school meals. Now they are also going to have standards for foods that compete with those school meals.

RAY SUAREZ: Will cafeterias and companies that make prepared foods have to really significantly change what's on offer in order to qualify to be sold in schools starting next year?

MARGO WOOTAN: You know, we have been working on this issue for a long time, about a decade.

And so, over that time, states have passed policies and individual school districts have passed policies. And so companies have been working to change the mix of products that they make available to schools. This is just going to make sure that it happens in almost all schools across the whole country.

RAY SUAREZ: Aren't some products totally out from now on?

MARGO WOOTAN: It is true that some things like regular candy bars, cookies, sugary sports drinks, and sodas are not going to be sold in schools during the school day. But there are lot of other foods that kids like that will be sold. They're going to have water, juice, milk, and carbonated water in all schools, plus lower-calorie beverages in high schools.

And then for snacks, there are things like granola bars, nuts, dried fruit, fruit cups. It will be a much healthier mix of products, but things that kids have seen and like.

RAY SUAREZ: Opponents and skeptics point to a Government Accountability Office report that found that in schools that were ahead of the curve on changing these policies, there were garbage cans piled high with things like apples and lower-calorie snack foods, higher-fiber baked goods. The kids just didn't want them, and they just didn't eat them.

MARGO WOOTAN: In most schools, actually, things are going very well.

It takes a little time for schools to figure out what products the kids like. You know, for years, for decades, they have been serving the same things. And so when you're cutting back on the junk and replacing it with healthier foods, you have got to figure out what products the kids like.

So, things like taste testing, having the kids vote for their favorite options, getting the kids engaged really helps. And in schools where they have been doing this for a while, the waste isn't a problem.

RAY SUAREZ: Sandra Ford, who is the president of the School Nutrition Association, remarked that, "The new meal pattern requirements have significantly increased the expense of preparing school meals at a time when food costs were already on the rise."

Is there going to be an economic difficulty in reaching some of these new goals?

MARGO WOOTAN: For school meals, USDA has been providing the main source of funding for those meals. And as a result of a law that was passed in 2010, the Healthy Hunger for Kids Act, USDA is now providing more resources to schools for the school lunch, an additional six cents in reimbursement, and also some changing in -- changes in pricing structure that bring more revenue in.

So these new revenues should be covering the costs. For those schools that are struggling, I think mostly we need to give them some more training and technical assistance to show them how they can serve healthy meals at a reasonable cost.

RAY SUAREZ: So this doesn't necessarily mean that kids heading to the vending machine or standing in the tray line in the cafeteria will have to spend more money?

MARGO WOOTAN: No.

The prices that the kids pay will stay the same mostly. They have been -- for the kids, middle- and upper-income kids, they have been trying to bring the prices of the school lunches in line with what it really costs. In the past, a lot of times, schools didn't charge what it actually cost them to prepare the meals for middle- and upper-income families. And so schools were losing member from that.

USDA is giving schools some advice and some guidance about how to sensibly price the foods in order to cover their costs. But schools can do a lot of things. They can form buying cooperatives with other school districts, so that they can get a better price. They can work out better contracts with schools -- with the companies that make the foods for food service.

So, there are things that lots of schools are doing to bring down the cost. We know that tens of thousands of schools around the country are serving healthy meals at the current reimbursement rate. For those schools that aren't, we just need to get them the training and technical assistance they need in order to do what other schools are doing.

RAY SUAREZ: Margo Wootan from the Center for Science in the Public Interest, thanks for joining us.

MARGO WOOTAN: Nice to be here.