Stoplights regulate car and pedestrian traffic. Could they also be used to regulate the food we eat?
Researchers at the Perelman School of Medicine at the University of Pennsylvania conducted a study to see how calorie labels on online food ordering systems, like Grubhub or Seamless, influence customer's purchasing decisions. The study, which was recently published in the Journal of Public Policy & Marketing, showed that images of stoplights helped consumers watch their calorie intake—about as effectively as displaying calorie numbers.
Conducted over a period of six weeks, 249 participants from Carnegie Melon University were asked to order lunch from a new online-portal, resulting in 803 orders placed overall. On this portal, all meal choices were presented with calorie information right next to the menu items, either as numeric listings or as a color-coded system of traffic light icons, where a red light means high-calorie, a yellow light means medium calorie, and a green light means low calorie.
What the researchers discovered was that presenting a menu item's nutritional information—whether a numeric value or a symbolic icon—reduced the amount of calories the average person consumed by 10%, compared to that information not being presented at all.
Although Eric M. VanEpps, the lead author of the paper, warns that "[future] studies looking at different menu types and sets of participants are necessary," he argues in the paper that the study "provides clear evidence that both calorie labeling methods can be effective when ordering meals online."
Not that food delivery companies have a choice in the matter. Starting in May 2017, the U.S. Food and Drug Administration will start requiring all restaurants, theaters, vending machines, and food delivery services to clearly label how many calories are in each item in an attempt to cut down on the alarming rise of obesity in the country. But perhaps numeric counters aren't necessary. As VanEpps's research suggests, familiar symbols can be just as effective.