Optimal Design of an Added-Sugar Menu Warning Label: A Randomized Experiment.

Abstract

Restaurant menu added-sugar warning labels have the potential to reduce added-sugar consumption. Label efficacy depends on noticeability. This study aimed to assess which design elements improve noticeability and recognizability and also assessed behavioral response to the labels. An online randomized experiment was used. A national sample of adults (N=4,083) was recruited to approximate U.S. distributions of sex, age, race, ethnicity, and education. A pretest-determined triangle shape was used for the label icon in the main experiment. The main experiment used a 3 × 2 × 2 × 2 factorial design to test label type (icon-plus-text versus boxed icon-only versus icon-only label), color (red versus black), size (150% vs 100% of menu text height), and placement (right versus left side of item name). Participants viewed fast-food and full-service restaurant menus displaying the assigned label next to high-added-sugar items (containing >50% of the daily recommended limit). Noticing a high-added-sugar label and recognizing one's assigned label among other labels were assessed and analyzed in 2024. Menu-ordering behaviors were also examined. Compared with icon-only labels, icon-plus-text labels increased the probability of noticing and recognizing high-added-sugar labels by 508% (7% vs 44%) and 263% (23% vs 82%) (ps<0.001), respectively. Red color increased noticing by 16% (p=0.020) and recognition by 20% (p<0.001) compared with black color. Larger height increased recognition by 13% (p=0.001). For icon-only labels, right placement increased noticing by 59% (p=0.020). Icon-plus-text labels reduced the probability of ordering a high-added-sugar item by 11% and the amount of added sugar ordered by 10.5 g (ps<0.001) compared with icon-only labels. Icon-plus-text labels were substantially more noticeable as high-added-sugar labels, recognizable, and efficacious at reducing the amount of added sugar ordered than icon-only labels. To a lesser extent, red color, larger labels, and right placement additionally improved performance, especially for icon-only designs, although they did not improve efficacy to a level similar to that of icon-plus-text labels. This trial is registered at AsPredicted.org (Number 156625) and ClinicalTrials.gov (NCT0620491).