Discussion
In this large randomized clinical trial, exposure to green “choose often,” single traffic light, physical activity, or nutrient warning front-of-package labeling systems led participants to select beverages and snacks with fewer calories compared with exposure to calorie labels alone. These 4 interpretative labeling systems also reduced selection of sugar from beverages and sugar and saturated fat from snacks. These results reinforce prior studies indicating that interpretative food labels are more effective at promoting healthier food selection than numeric labels.The 4 interpretative labeling systems led to similar effects on beverage and snack calories selected regardless of participants’ education level. To our knowledge, this is among the largest randomized trials to examine whether the effects of interpretative food labels differ by education level.In general, the 4 interpretative labeling systems performed similarly to one another in their effects on calories, sugar, saturated fat, and sodium selected from beverages and snacks. By contrast, the 4 interpretative labeling systems differed in how they affected psychological outcomes. For example, the nutrient warning labels elicited the most attention, thinking about health effects, and negative emotions, followed by the physical activity and traffic light labels. The green labels elicited the least attention, thinking about health effects, and emotions. Because these reactions are associated with behavior change,This study is among the first to examine the effects of interpretative food labeling systems on stigma,Together, these results suggest that policymakers have a variety of promising policy options when selecting an interpretative front-of-package labeling system to encourage healthier purchases. Policymakers’ choice of system might depend on how they weigh different criteria (eg, whether high trustworthiness or low stigma is more important). Policymakers might also consider how each system could further other goals, such as whether certain systems are more likely to elicit beneficial product reformulation