Trends in Self-Reported Responses to Nutrition Facts Labels Before and After Nutrition Labeling Policy Implementation: A Comparison of Adults in the United States and Mexico

Background In 2020–2021, both Mexico and the United States implemented similar, newly formatted nutrition facts labels (NFLs). Mexico simultaneously implemented front-of-package warning labels (FoPWLs), which emphasize high amounts of less healthy nutrients described in NFLs (e.g., calories, sugar, salt, trans fat, and saturated fat) to enhance consumer understanding of nutrition information. Objectives To evaluate these policies by comparing pre- and postpolicy trends in self-reported responses to NFLs. Methods Annual surveys from the adult International Food Policy Study (2018–2023) were analyzed for Mexico (n = 24,832) and the United States (n = 25,464). Outcomes included reported ease of finding nutrition information in grocery stores and awareness, use, and understanding of NFLs (all measured on 1–5 Likert scales). A difference-in-differences method using adjusted and weighted linear regression models compared cross-country differences in trends for these outcomes over the transition (2019–2020), early (2019–2021), mid (2019–2022), and late (2019–2023) postimplementation periods relative to prepolicy trends (2018–2019). Results Trends over the transition period (compared with prepolicy) were stable within and across countries. For all outcomes, trends up to the early implementation period (compared with prepolicy) were more positive in Mexico than in the United States (i.e., ease of finding nutrition information B = 0.195, P = 0.003; awareness B = 0.220, P < 0.001; understanding B = 0.332, P < 0.001; and use B = 0.211, P = 0.006), driven by both increases in Mexico (i.e., ease of finding B = 0.126, P = 0.008; awareness B = 0.132, P = 0.001; understanding B = 0.198, P < 0.001; and use B = 0.087, P = not significant [ns]) and decreases in the United States (i.e., ease of finding information B = ns; awareness B = −0.088, P = −0.049; understanding B = −0.134, P = 0.002; and use B = −0.124, P = 0.025). When evaluating mid and late postimplementation periods, contrasts favored Mexico over the United States for all outcomes, except NFL use, which did not differ within or across countries. Conclusions Newly formatted NFLs in the United States did not increase awareness, understanding, or use of NFLs, particularly when compared with Mexico’s new NFLs that were accompanied by FoPWLs. Further research should determine the labeling effects on eating behaviors.