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Traffic-light labels – a benefit for public health

Comment by Torben Joergensen, EACPR Prevention, Epidemiology & Population Science Section

Traffic-Light Labels and Choice Architecture: Promoting Healthy Food Choices
A. N. Thorndike et al.
American Journal of Preventive Medicine, Volume 46, Issue 2 , Pages 143-149, February 2014


This article analyses the effectiveness of traffic-light labelling and choice architecture in a cafeteria over a two year period. The setting was a large hospital cafeteria in Boston with more than 6,000 transactions daily. All food items were labelled as red, yellow or green based on three positive criteria (fruit/vegetable, whole grain, and lean protein/low fat diary as the main ingredients) and two negative criteria (saturated fat and caloric content). Items with more positive than negative criteria were green, items with equal positive/negative criteria were yellow and items with more negative than positive criteria were red. Besides labelling of food items, the choice architecture of the cafeteria was changed, so that the green labelled items were more assessable than the red labelled items.

The authors compared the sale of the different items before and after the intervention and also followed a group of more than 7,000 employees, who used a platinum plate card to pay for purchases in the cafeteria.

After one year they saw an increase in green labelled items and a decrease in red labelled items both as regards food and beverages. These changes remained after two years. The changes were equal among races and personnel with different educations. Furthermore, it was shown that the total sale in the cafeteria was stable or even slightly increasing.

This is a very interesting study showing that simple labelling and choice architecture in a cafeteria can give long term changes in more healthy choices among personnel. At the same time it does not influence the earnings in the cafeteria. This is a clear signal that these structural changes will be of benefit for public health. It has often been proposed that a simple traffic labelling system would help people to make the right choices, but this has been severely opposed by industry claiming no effect of such a labelling. Knowledge of the study deserves to be widespread; with special emphasis that total sale is not influenced.

The drawback of the study is that there was no control group and being a hospital cafeteria in an urban setting in the United States may not be generalisable to all settings. It therefore should be repeated in other settings in other countries.