America is a heavy place. More than two-thirds of adults and one-third of preschoolers are either overweight or obese, and similar proportions can be found in many western countries.
One significant cause of this problem is a diet that is rich in calories and poor in nutrient-rich vegetables. Our food intake habits are shaped significantly in our younger years, and youth tend not to be overly excited about vegetables. Give a child a choice between fries and carrots, and carrots don't fare so well. However, if we cannot get children to eat healthy now, we are likely staring down the barrel of obesity rates that will continue to rise.
Several interventions have been proposed to encourage youth to eat more vegetables, particularly in their school cafeterias. The school is an important place, as children are minimally supervised but eat a significant amount of their daily food intake on site. Many proposed solutions are expensive, difficult to implement, and result in modest behavior changes.
There is one noteworthy exception, and it is delightfully simple. In a study by Joe Redden and his colleagues at the University of Minnesota published in the Journal of the American Medical Association this month, the authors showed a simple way to get students in a lower-income school cafeteria to eat more vegetables. How? Pictures.
The authors placed pictures in cafeteria lunch trays. The photo showed veggies in one of the lunch plate compartments, suggesting that other students typically placed vegetables in that compartment. The results? Children put more veggies on their plates. The cost? About $12 and two hours of time, for 600 children.
Why was this so effective? Social psychology has long shown the power of social norms. We often do what others are doing, and conforming (or fitting in) is a goal especially powerful to children. If everyone starts listening to a certain band, many will follow. Of course, if smoking or underage drinking becomes common, it is hard to stop youth from doing that too. In this case, the mere illusion that vegetable choice is common among their peers increased the likelihood of including a veggie as a part of their lunch.
Convince students that carrots are good for their health (say, through more education), and still only a few choose to eat them. Youth already know that carrots are good for their health and smoking is bad, but they rarely act in accordance with their own best health. Neither do adults. How can we expect youth to do any better than us? However, convince students that their friends all eat carrots, and carrots become more attractive. Since the strongest predictor of what we eat is what we put on our plate, most of the additional veggies were actually eaten, rather than tossed in the trash.