Objectives. To synthesize empirical evidence about the effects of mandatory front-of-package nutrition labeling policies on behavioral and cognitive outcomes related to food choice, and on socioeconomic and demographic inequalities in these outcomes.
Methods. A systematic review was conducted in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) 2020 guidelines. The following databases were searched for publications in English and Spanish: MEDLINE on Ovid, ScienceDirect, Scopus and LILACS. The search had no date restrictions. Two reviewers independently screened titles, abstracts and the full text of articles, with disagreements resolved by a third reviewer. Studies were eligible for inclusion if they evaluated the implementation of mandatory front-of-package labeling and reported relevant outcomes. Risk of bias was assessed using the Cochrane Risk of Bias 2 tool, the Risk of Bias in Non-Randomized Studies of Interventions tool and the Newcastle–Ottawa Scale. Findings were synthesized narratively.
Results. Seven studies met the inclusion criteria, covering four countries with mandatory labeling policies (Chile, Colombia, Ecuador and Mexico). The studies used diverse designs, including interrupted time-series, natural experiments, experiments and cross-sectional surveys. Octagonal warning labels were associated with increased awareness and understanding, as well as reduced purchase or selection of products high in sugar, sodium or saturated fat. Evidence of socioeconomic and demographic inequalities was heterogeneous and insufficient to establish consistent patterns across population groups.
Conclusions. Mandatory front-of-package nutrition labeling policies, especially octagonal warning labels, improve intermediate outcomes such as consumer awareness and food choices. The limited empirical evidence from heterogeneous evaluations provides little insight into long-term health impacts or socioeconomic and demographic inequalities.