The study, which was co-authored by Cornell University professor David Just, focused on seven elementary school cafeterias in Orem during the spring and fall of 2011.

Researchers documented the amount of fruits and vegetables being thrown away by students at those schools, Price said, then repeated the observation in the fall, when three of the seven schools switched to a recess-first schedule.

Price said that when lunch comes first, students skip portions of their meal to get outside to the playground more quickly. At the same time, he said, serving lunch after recess means kids work up an appetite and are more willing to clean their plates.

"Not only do kids eat more vegetables, but they throw less away," he said. "For a school trying to serve good fruits and vegetables, its encouraging to know you can get more in the tummy and less in the trash."

Schools in Utah and around the country have complained of increased food waste after new healthy lunch guidelines were mandated in 2010. The Healthy, Hunger-Free Kids Act set caps on calorie counts and portion sizes while requiring whole grains and an increase in healthy food options.

"When it first came out, it was pretty dramatic the food waste that we saw," Cherry Hill Elementary Principal Alisa Hart said of the new guidelines. "You can have the most healthy lunch menu out there, but if kids dont want to eat it, it doesnt matter."

Cherry Hill was among the schools that participated in the BYU study, Hart said, but has continued to serve lunch before excusing students for recess.

Hart said the school tried reversing the order of lunch and recess more than a decade ago, but the experiment led to scheduling headaches and was abandoned. Cherry Hill lunchroom managers didnt see a big difference in food waste at the time and it was difficult to get students to come in off the playground for lunch.

"When youre sending groups of kids out and then bringing them in to eat, its just a little bit more difficult to schedule," she said.

Suncrest Elementary is in its third year of dividing students into grades that eat before recess and grades that eat after recess.

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BYU study: Kids eat more vegetables after recess