Purpose The purpose of this paper is to analyze the effect of nutritional warning (NW) labels on the behavior of consumers of processed foods, considering demographic and psychological factors associated with the theory of planned behavior (TPB). Design/methodology/approach The study had a descriptive and cross-sectional design. A survey was applied to 200 household food decision makers from central Chile. This questionnaire was developed based on the planned behavior theory that evaluates the psychological constructs of human behavior: Attitude (ATT), Subjective Norms (SN), Perceived Behavioral Control (PBC) and Purchase Intention (PI) toward processed foods with NW. Sociodemographic variables were also included. The data were analyzed by using a multinomial logit (MNL) model, where three types of categories are established depending on the choice made by the consumer. Thus, the dependent variable responds to the effect of the following probabilities: Eliminate from Consumption, Do Not Eliminate from Consumption and Do Not Know whether or not to eliminate from consumption when selecting a food processed with NW. Findings The results show that the implementation of NW has significant effects on the choice of processed foods purchases made by Chilean consumers. Consumers with negative ATT and PBC in the presence of NW on processed foods eliminated this type of food from their consumption. On the other hand, those who did not eliminate processed foods with NW from their consumption made that choice because they had a positive PBC. In addition, consumers who were unsure about eliminating or consuming processed foods with NW also had a positive PBC. In addition, SN and sociodemographic variables did not affect consumer choice. Practical implications The results of this study are crucial in informing public policy strategies seeking to alert consumers about the content of processed foods, thus raising awareness for decision making in order to reduce noncommunicable diseases associated with poor eating habits. Originality/value The study provides evidence on the effect of NWs for processed foods on consumer decisions based on the TPB.