If a child is coming home hungry after school more than usual, the reason might be the better intentions of his school cafeteria.

The long-awaited U.S. Department of Agriculture standard upgrades on school lunches have finally gone into effect this year. Though kids might argue (and, in fact, there has been widespread grumbling. See a parody of the the food offerings made by Kansas student below ), experts say the changes are a marked improvement from the notoriously unhealthy lunch food that has drawn criticism in recent years.

The new guidelines come just in time to combat a wave of bad publicity for schools on this point. Last year there was a burst of attention on the appetizing and artery-clogging offerings in public schools thanks to books like “Fed Up with Lunch,” and celebrity chef Jamie Oliver’s activism.

Advocates felt vindicated when the USDA took up the mission to revise out-of-date standards. But the process soon became mired in lobbying, with the government definition of vegetables stretched to include pizza.

Though watered-down, the changes generally have been praised.

I asked Jessica Donze Black, director of the Kids’ Safe and Healthful Foods Project, to explain the changes and how tangible they are to most kids diets.

Here’s our Q&A:

(Ed Andrieski/AP)

Black: The USDA is supposed to update the standards about every five years to make sure that they reflect the most up-to-date nutrition science. However, there was a lapse in updating, so the new standards released last winter were the first update in more than 15 years. As a result, the changes are noteworthy and students are getting more of the foods and nutrients they need without getting excess fat, sodium and calories. Key differences include:

●Schools are now required to serve more fruits and vegetables in greater variety throughout the week.

●Meals must include more whole grains. At least 50 percent of grains served must be whole grains.

●Only low-fat or non-fat milk can be served.

●While fruit and vegetable portions have increased, some entree portions may have decreased since meals are now required to be within calorie ranges.

●Meals must be lower in saturated and trans fat.

D’Arcy: Are the standards binding or are they goals?

Black: The standards are goals intended to be met by all schools, and they actually have an incentive to do so. All schools meeting the updated standards will receive an additional 6 cents of reimbursement from USDA per meal served this year. This may not sound like much, but it can make a big difference to schools that are making these changes... Thousands of schools have already successfully taken on the challenge and made major improvements to their food.

D’Arcy: In the best of all worlds, how might they affect a child’s lunch choice?

Black: Currently, one in three children is obese or overweight. Many young people today consume too many calories, fat and sodium while getting too few fruits and vegetables, whole grains and low-fat or non-fat dairy foods. This put kids at risk for a range of chronic diseases such as type 2 diabetes, heart disease and asthma.

The improved meal standards are intended to meet one-third of the daily needs of the average child. Therefore, children who consume a school lunch will get what they should be eating — fruits, vegetables, whole grains, etc. — and less of what they tend to overeat — calories, fat, saturated fat, and sodium.

D’Arcy: In the real world, how do they affect lunch choice?

Black: There is wide variation among school districts since the standards simply present a framework for the meals. The specific meals served, the variety of options available and the presentation of those options to students are all decided locally. Thus, there are school districts that have done a tremendous job in providing healthy, delicious options to students in a way that encourages kids to try them, which results in kids enjoying these new foods. There are other school districts that are lagging behind or offering meals in such a way that they are less appealing to their student consumers.

D’Arcy: There’s recently been evidence that junk food offerings have increased substantially in schools. Do the guidelines limit the availability of junk food and caloric drinks?

Black: These guidelines only apply to federally-subsidized school breakfast and lunch. However, Congress also directed USDA to update the standards that guide the rest of the school food environment including vending machines, school stores and a la carte foods. These guidelines are expected to be released closer to the end of the year and could dramatically affect the snacks and beverages available to students outside of the often more balanced school meal.

D’Arcy: What are next steps parents might take to push schools even further in the direction of healthy offerings?

Black: Since most of the decisions about what foods are served in schools are made locally, parents have a major role to play in making those decisions. If they would like to see more or different variety of foods, they should talk with their cafeteria manager or district nutrition services director to find out what changes have been made or are being considered.

Parents might also consider volunteering to help with implementation such as staffing taste tests of new foods or helping promote improved menu options to students or parents. They can also play a role in the national decision making process by offering their insight to USDA and to Congress. We encourage them to come to www.healthyschoolfoodsnow.org and sign up to take action so they can stay informed about what is happening and how to get involved.

Are you concerned about how your child eats during the school day? Have you seen a difference in your school’s cafeteria offerings?

Related Content:

Sarah Wu: Fed up with school lunch and with being anonymous

Childhood obesity epidemic: Whose fault?

Fighting the childhood obesity epidemic: Are ‘food rules’ the solution?