Sociodemographic differences in the understanding of front-of-pack nutrition labeling, perception of healthfulness, and food purchase intention in Brazil.

While nutrition claims draw attention to desirable nutrient qualities, the Brazilian Front-of-Pack Nutrition Labeling (FOPNL) system serves a contradictory purpose by signaling excessive levels of added sugar, saturated fat, and sodium. Besides labeling, sociodemographic factors may influence the understanding of nutritional information and food choices. This experimental, controlled, and randomized study used secondary data derived from previously published research to evaluate the impact of sociodemographic variables, including region, sex, age, education, and income. Specifically, we analyzed how these factors influence the understanding of nutritional information, the perception of healthfulness, and the purchase intention of products with different FOPNL models and nutrition claims. A sample of 720 Brazilian adults completed an online questionnaire, being randomly assigned to one of four FOPNL conditions: control (without FOPNL), octagon, triangle, or magnifying glass. Participants evaluated 12 label panels in a 3×2×2 factorial design, considering 1) food category, 2) number of nutrients in excess and 3) presence/absence of nutrition claims. Understanding of nutritional information was measured as the ability to correctly identify nutrients in excess using a generalized linear model with binary logistic regression. Perception of healthfulness and purchase intention were assessed on a 7-point scale using mixed analysis of variance models, with the sociodemographic variables (region, sex, age, education, and income) as fixed effects and participants as random effects. The results indicate that sociodemographic variables did not significantly affect the understanding of nutritional information. However, participants aged 25 to 34 and male participants reported higher perception of healthfulness and greater purchase intention compared to other groups. These findings suggest that, although the provision of nutritional information on packages supports informed food choices across diverse sociodemographic contexts, age and sex specifically influenced how consumers perceived product healthfulness and their likelihood of purchasing the presented items in this sample.