It might only be a matter of time. (AP Photo/Pablo Martinez Monsivais)

Schools appear to be serving lunch at the wrong time -- and it could be taking a toll on your child's nutrition.

That's according to a new study, which concludes that convincing children to eat their greens could be as simple as scheduling lunchtime a little later in the day. The study, which was conducted at seven different schools in Utah, found that kids consistently waste more food when lunch is scheduled before recess. And that waste is largely comprised of their meal's healthiest items: fruits and vegetables.

Researcher's at Cornell and Brigham Young University spent 14 days observing the behavior of school children during lunchtime at each of the seven elementary schools—three of which held lunch after recess, while the remaining four served kids food before recess. After tallying how many fruits and vegetables children tossed away, as well as how many servings of the two students actually ate, over the course of the two weeks, a clear trend emerged.

Students who ate lunch after recess ate 54 percent more fruits and vegetables than those who ate it before. The number of students who ate at least one serving of fruit and vegetables was also significantly higher—45 percent greater, to be exact—at the school's let kids play before eating.

Why? The answer is wonderfully simple: Kids are not only hungrier after exercising, but also are less likely to rush their meal so they can go out and play.

"Recess is often held after lunch so children hurry to 'finish' so that they can go play—this results in wasted fruits and vegetables," David Just, one of the study's authors, said in a statement. "If recess is held before lunch, students come to lunch with healthy appetites and less urgency and are more likely to eat their fruits and vegetables."

This isn't the first time researchers have explored the relationship between when children eat and how it might affect their appetite. A 2014 study concluded, similarly, that scheduling lunch before recess leads to more food waste for roughly the same reasons. And there is even a movement called Recess Before Lunch, the purpose of which hardly needs to be explained. But this latest study looks specifically at how a simple school schedule can dramatically affect whether children consume healthier foods, such as fruits and vegetables.

It's unclear how many schools currently schedule lunch before recess, but the answer is likely, and disconcertingly at that, many. As of 2001, after all, only 4.6 percent of elementary schools reported holding recess before lunch. Given the growing evidence that doing so not only saves food, but also money—the authors cited a study that found holding recess before lunch leads to a savings of roughly 14 cents per meal—and, potentially, children's nutrition, it seems that working to reverse the long-held tradition would make a lot of sense.