Health literacy as a moderator of menu labeling effects on fast-food ordering: an online randomized controlled trial.

Abstract

Objectives: To examine whether functional health literacy moderates the effects of menu labeling formats on fast-food ordering behavior.

Methods: A total of 2829 US adults completed an online randomized controlled survey in 2022. Participants viewed 1 of 8 menus in a 2 × 2 × 2 factorial design varying calorie labels (present/absent), sodium stoplight icons (present/absent), and "all-natural" claims (present/absent), then selected an entrée, side, beverage, and optional dessert. Linear regression models tested main and interaction effects of labeling formats and functional health literacy on total calories and sodium ordered, adjusting for sociodemographic characteristics, fast-food consumption frequency, and typical ordering patterns.

Results: In covariate-adjusted within-literacy comparisons, several labeling experimental conditions were associated with lower-calorie and lower-sodium selections among participants with moderate functional health literacy, whereas no significant differences were observed among participants with low or high literacy. Significant differences among moderate-literacy participants ranged from 90 to 135 fewer calories and 123 to 154 mg less sodium compared with the control condition (nominal P < .05).

Conclusion: Menu labeling effects were not uniform in this online fast-food ordering experiment. Their impact depends on consumers' ability to interpret basic nutrition information. Designing more intuitive labels may improve the equity and effectiveness of restaurant nutrition policies.