To health-minded PTA parents, it must have seemed a good idea at the time: Reduce sugar and milk fat in kids’ diets by banning chocolate milk from elementary schools and substituting skim.

But children in 11 Oregon schools, surveyed by the Cornell Center for Behavioral Economics in Child Nutrition Programs, had other ideas.

“Banning chocolate milk backfired; milk sales dropped by 8 percent, 29 percent of white milk was thrown out, and 7 percent of kids stopped eating school lunch altogether,” reports Andrew Hanks, lead author and research associate in the behavioral economics center, based in the College of Agriculture and Life Sciences. “This is probably not what parents wanted to see.”

The Cornell study, published April 16 in the online science journal PLOS ONE as “A Pilot Study Evaluating the Cafeteria Consequences of Eliminating Flavored Milk,” tells what happens when chocolate milk-loving kids are suddenly confronted with something thinner and paler. The article proposes what researchers hope can be a healthful compromise.

“Members of the school district’s PTA were adamantly opposed to offering chocolate milk in the cafeterias, claiming it was as bad as soda,” Hanks recalls. “While this policy does eliminate the added sugar in chocolate milk, it also introduces a new set of nutritional and economic consequences. Children typically don’t choose foods for health, but rather for taste.”

Nutritionally, after the milk substitution, students consumed less sugar and fewer calories; however, they also consumed less protein and calcium.

Here’s what the behavioral economics experts propose: “Instead of banning chocolate milk, make white milk appear more convenient and more ‘normal,’” says Hanks. “Put the white milk in the front of the cooler, and make sure that at least one-third to half of all the milk is white. We’ve found that this approach can increase sales by 20 percent or more!”

Other authors of the PLOS ONE study were professors David Just and Brian Wansink, of Cornell’s Charles H. Dyson School of Applied Economics and Management. The study was self-funded by the Cornell Center for Behavioral Economics in Child Nutrition Programs.