Traffic-Light Labels and Choice Architecture

An elderly man collecting a meal in a cafeteria.

Hospital cafeteria patrons make healthy choices again and again when given easily understood information about food offerings.

The Issue:

Food signs that clearly communicate which foods are healthy and which are not in workplace cafeterias have the potential to influence customers’ purchases over time. A large hospital cafeteria provided the environment to test the impact of traffic-light signs (green indicating a healthy choice, yellow less healthy, and red unhealthy) and of locating healthy foods more conveniently (choice architecture).  

Key Findings

  • Purchases of all red items decreased from 24 percent at baseline to 21 percent at 12 months, and remained at 21 percent at the 24-month follow-up.

  • Purchases of all green items increased from 41 percent at baseline to 45 percent at 12 months and 46 percent at 24 months.

  • Purchases of red beverages decreased from 27 percent at baseline to 17 percent at 12 months and 18 percent at 24 months.

  • Purchases of green beverages increased from 52 percent to 59 percent at 12 months and 60 percent at 24 months.

  • Repeat customers (at least 10 purchases every 3-month period) and less frequent users (no purchase made) had similar changes in green and red purchases at the 24-month follow-up.


Simple food environment interventions can change food/beverage purchasing behaviors over a sustained period without decreasing sales.

About the Study:

Researchers analyzed transactions for all customers and for a longitudinal cohort of 2,285 Massachusetts General Hospital employees who regularly used the cafeteria. The traffic-light labeling system was based on U.S. Department of Agriculture dietary recommendations.

Infographic: Can a Traffic Light Guide You to Make Healthier Choices