Researchers at the University of Minnesota have found a way to get more school kids to eat veggies: Line their lunch trays with photographs of those foods.

That simple tactic more than doubled the number of kids eating green beans and more than tripled the ones eating carrots in a study the researchers conducted last spring at an elementary school in the Twin Cities suburb of Richfield.

The study’s findings were published online today in the Journal of the American Medical Association (JAMA).

“We expected this to work because there are other studies in the literature showing that small changes to the eating environment can lead to big changes in behavior,” said Traci Mann, an associate professor of psychology at the U of M and one of the authors of the study.

“We also expected it to work,” Mann added, ” because we were inducing a norm. We were giving kids the impression that [filling a particular part of their tray with a particular vegetable] was what people did. And norms have a powerful effect on behavior.”

Still, the researchers were surprised to see how well their tactic worked. “Tripling the number of kids eating carrots is amazing,” Mann said.

And, unlike other interventions — such as bringing in trained instructors to teach kids about the importance of eating fresh fruits and vegetables — this one was inexpensive to implement. It involved no special training and cost very little: about $3 for photocopying and 20 minutes of labor time per 100 trays.

How it was done
The study was conducted at the Richfield S.T.E.M. School (a K-5 school formerly called Richfield Intermediate) on two days last year when the school was serving identical meals. On both days, the students were able to help themselves to servings of applesauce, orange slices, green beans and carrots, while the kitchen’s staff served them the rest of the meal. But on one of the days, the compartments on the kids’ lunch trays were lined with photographs of carrots and green beans.

During each meal, the researchers counted how many kids selected beans and carrots. Then, after the meal was over, they gathered up all the veggies that were left in the lunchroom — on the trays, on the table and, yes, even on the floor.

“We collected all that up — yum, yum — and weighed it,” said Mann.

They found that on the control day, 6.3 percent (42 of 666 kids) took green beans compared to 14.8 percent (96 of 647 kids) on the intervention day. The photos made carrots an even bigger culinary hit. Some 11.6 percent (77 of 666 kids) put them on their trays on the control day compared to 36.8 percent (238 of 647 kids) on the intervention day.

Now, getting the kids to take the beans and carrots was one thing. Getting them to eat the veggies was another. The kids ate about the same amount of beans (an average of 19 grams per child) on both days of the experiment. And they ate slightly less carrots on the intervention day (an average of 27 grams per child, which compared to 31 grams per child on the control day).

“It was just the teensiest bit less per student, but it was more students,” said Mann. “We’re still happy, especially because three times as many students ate those 27 grams.”

Barriers to implementation
Deb LaBounty, nutrition services supervisor at the Richfield Public Schools was happy, too. She thought the photo idea would work from the moment the U of M researchers contacted her about testing the tactic in one of her schools.  

“Kids are always looking for examples,” LaBounty said in an interview Tuesday.

LaBounty also understands how small changes can alter eating behavior. Her school district was able to get kids to eat more applesauce by simply increasing the serving size from half a cup to a cup, she said. “Even adjusting the lighting to make the food look better, like they do in restaurants,” can encourage kids to eat more healthful foods, she added.

But LaBounty is not yet sure how she’ll be able to translate the current study’s findings into practical action. She said she talked to a vendor who supplies kitchen trays and “he just didn’t think they could get [the photos] to work on plastic trays,” she said.

She’s currently exploring the option of using recyclable cardboard trays, which would work with photos.

“It’s just figuring out the logistics of making it happen,” she said.

Mann and her coauthors, who come from U of M’s departments of marketing, applied economics, and food science and nutrition as well as psychology, have been researching other tactics for getting school kids to eat more healthful foods. They’ll be publishing the results of those studies later in the year, she said.

The JAMA study was funded in part with a grant from the U.S. Department of Agriculture.