The L.A. menu went beyond the national guidelines, which already impose strict guidelines on calories, portion sizes, whole grains, and vegetables. Today, for example, a student at Griffith Junior High in East L.A. would have a choice between a veggie burger or a cheese sandwich (on whole wheat bread), as well as potato wedges, chilled apricots, and milk.

But a new study suggests that despite the softened menu standards, students are still beelining toward carbs and meat and avoiding fruits and vegetables.

For the study, published in the April issue of Preventative Medicine, researchers examined the lunch trays of 2,000 randomly selected Angeleno middle schoolers over five consecutive days. Though the students are offered a fruit and a vegetable each day, 32 percent of students did not take the fruit from the line, and almost 40 percent did not take the vegetables. Among those who did take a fruit or vegetable, 22 percent threw away the fruit and 31 percent tossed the vegetables without eating a single bite.

So in essence, just over half the students both took and ate some fruit, and about 42 percent both took and ate a vegetable.

Salads were the most common vegetable to be left untouched, while whole fruits, like apples and oranges, were far less popular than fruit cups or juices. Girls were both more likely to take fruits and vegetables from the line and were less likely to waste them.

“We need to do more to get our kids well-prepared for an adulthood of eating vegetables with gusto,” said William J. McCarthy, one of the study authors and a health policy professor at the University of California Los Angeles. “There are downstream medical costs to this in the form of diabetes and heart disease.”

The vegetable rejection has other downsides, too: Students in L.A. throw out at least $100,000 worth of food a day, as the L.A. Times recently found.

But McCarthy says that it’s better for students to take the produce, try it, and throw the bulk away than to not take it at all. Humans have a “neophobic response to new plant tastes,” he said. “If you travel and are introduced to new plant food, your body instinctively says, ‘No, I don’t like it.’”

This was nature’s way of keeping our paleolithic forbears from OD-ing on toxic mushrooms. But for modern humans, the natural aversion means it takes eight to 10 exposures, on average, for a child to learn to like a new vegetable.

To help make kids hungry for frisée rather than fries, McCarthy recommends that schools move recess to occur before lunch, with the idea that exercise increases appetite for water-dense foods. And he said a school garden can go a long way in helping kids feel ownership and familiarity with greens.

Overall, the results are frustrating news for school lunch programs. It’s much easier for administrators to add produce to a menu than it is to convince 7th graders that kale is cool. L.A. Unified is now working with districts in New York, Chicago, Dallas, Miami and Orlando to spread the doctrine of healthy lunch food nationally. Let’s hope those areas think about how to get kids to actually eat the food that they spend months puzzling over.