Understanding, perceived food healthiness and self-reported food purchase behaviors in Chilean mothers of preschoolers and adolescents: a natural experiment after the first year of the Food Labeling and Advertising Law

Chile has one of the highest global obesity rates, particularly among children, with diet-related chronic diseases being the leading cause of death. To combat this, the Chilean government implemented the 2016 Law of Food Labeling and Advertising, which introduced front-of-package warning labels (FOPL), marketing restrictions, and sales prohibitions on foods high in added sugars, saturated fats, sodium, or excessive energy content. This study assessed the impact of the warning FOPL on understanding, perceived healthiness of food products, and self-reported purchasing behaviors among 889 mothers of preschoolers and 740 adolescents from low-middle income backgrounds after one year of implementation. A pre-post quasi-experimental study was conducted using data from the Growth and Obesity Cohort Study (GOCS) and the Food Environment Chilean Cohort (FECHIC). Surveys were administered before (2016) and after (2017) implementation to evaluate comprehension of the FOPL, changes in perceived food healthiness, and shifts in purchasing decisions. Logistic regression models adjusted for key covariates analyzed changes over time. Most participants (mothers: 96%; adolescents: 93%) correctly identified warning labels as indicators of unhealthy food. The perceived healthiness of sugar-rich products decreased significantly (p<0.001). Use of nutritional information when purchasing food increased among mothers (56% to 70%) and adolescents (23% to 31%), with 50% of mothers and 39% of adolescents specifically using the FOPL in decision-making. The warning FOPL was well understood, highly valued, and contributed to improved nutritional perceptions and purchasing behaviors among low-middle income populations. These findings support the effectiveness of warning labels as a public health strategy to encourage healthier dietary choices.