Warning labels have been implemented in different countries around the globe, including Brazil, to encourage healthier food choices. The aims of the present study were to evaluate the relative effect of different warning labels, brands and nutrition marketing claims on the food choice after the implementation of the Brazilian front-of package nutrition labelling regulation. Packages of four categories were designed considering the following factors: brand (familiar vs. unfamiliar), nutritional warning (present or absent), textual nutrition marketing claims (present or absent) and visual nutritional marketing claims (present or absent). A total of 850 Brazilian adults were recruited by a marketing agency. Participants were randomly allocated to one of two experimental conditions: black magnifier (n = 403) and black octagon (n = 447). They completed a choice task involving two out of four product categories: chocolate flavored milk, cookies, granola, and iced tea. The packaging was designed considering four factors: The presence of warning labels encouraged product choice in three of the four categories. However, brand and textual nutrition marketing claims had a larger effect. These results suggest the need to introduce comprehensive packaging regulations to reduce the prevalence of nutrition marketing claims on unhealthy products, as well as communication campaigns to raise awareness of the benefits of taking into account warning labels when making food purchases