These low-cost/no-cost solutions leverage the natural psychology of choice that teenagers use when choosing their lunch. Such behavioral solutions deserve our attention for three reasons. First, they have dramatic results—many are three to five times more effective than more traditional policies. Second, these solutions are inexpensive. Many can be triggered by simply rearranging the food that is already in the line. There are no new recipes, no implementation costs, and no equipment that would cost more than $50. Third, these solutions do not generate the type of reduction in lunch participation that has become the norm in schools that have taken the escarole-and-tofu approach and have eliminated the cookies and chocolate milk. High participation is good not only for schools seeking more sustainable finances but also for the children who might otherwise choose to skip lunch, or bring less healthy Lunchable-like food from home.

To help make lunchrooms smarter, the USDA is taking a big step forward in supporting these more innovative and sustainable solutions through its recent funding of our Cornell Center for Behavioral Economics in Child Nutrition Program. The goal is to encourage researchers and schools to work together in finding solutions to make lunchrooms smarter that are easy and cheap—or even free. For instance, if a school requires students to pay with cash when buying cookies (disallowing debit purchases on less healthy food), children buy fewer cookies and more fruit. If a school puts healthier foods at the front and end of a line, children take more than if they are in the middle.

Food isn't nutritious until it is eaten. We don't improve school lunches by making children take healthier items. When healthy foods are forced upon them, children will resist and dislike not only the heavy-handed approach but also the food associated with that heavy hand. We improve school lunches by nudging children to make the right choices on their own. That way, when they take the apple instead of the cookie, it was their idea.

For more details about lunchroom redesign strategies, visit NYTimes.com to see Just and Wansink's interactive op-chart.

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