A team of researchers at Massachusetts General Hospital set up a program in their large hospital cafeteria that uses color-coded “traffic-light” food labeling and they also made changes in the way popular items are displayed. Researchers say the changes in the proportions of more and less healthy foods purchased in the months after their program began have lasted up to two years after the labeling intervention was in place.
The program was initiated in March, 2010, to deliver information about healthy food choices in a simplified way that did not require reading and understanding food labels. The first phase involved the application of “traffic light” labels to all cafeteria items: green for the healthiest items, like fruits, vegetables, and lean protein; yellow for less healthy items; and red for items with little or no nutritional value. The second “choice architecture” phase, started three months after the labels were introduced, focused on cold beverages, pre-made sandwiches and chips—all were rearranged to display more healthful items where they were most likely to be selected. For example, diet drinks, bottled water, and low-fat dairy products were placed at eye level, while beverages with yellow or red labels were placed at lower levels.
The current study analyzed purchase patterns for the 2 years following the program's implementation. Researchers found that the changes at the end of the first year were almost unchanged at the end of the second. Overall, purchases of "green" items had increased 12 percent, compared with the pre-intervention period, and "red" item purchases dropped 20 percent. Purchases of "red" beverages – primarily sugar-sweetened beverages – dropped 39 percent, while "green" beverage purchases increased 10 percent. The changes remained similar for all types of employees, and overall cafeteria sales during the two-year period were stable.