To examine whether traffic-light labeling and choice architecture interventions improved dietary choices among students at a northeastern US university.
In 6 cafeterias at Harvard University, in Cambridge, Massachusetts, we implemented a 7-week intervention including traffic-light labeling (red: least nutrient rich; yellow: nutrient neutral; green: most nutrient rich), choice architecture (how choices are presented to consumers), and "healthy-plate" tray stickers. During the 2014-2015 academic year, 2 cafeterias received all interventions, 2 received choice architecture only, and 2 were controls. We analyzed sales for 6 weeks before and 7 weeks during interventions. Using interrupted time-series analyses, we measured changes in red, yellow, and green items served. We collected 1329 surveys to capture perceptions of labeling.
Among 2.6 million portions served throughout the study, we found no significant changes in red (-0.8% change/week; P = .2) or green (+1.1% change/week; P = .4) items served at intervention sites compared with controls. In surveys, 58% of students reported using traffic-light labels at least a few times per week, and 73% wanted them to continue.
Although many students reported using traffic-light labels regularly and wanted interventions to continue, cafeteria interventions did not demonstrate clear improvements in dietary quality.