Harnessing the power of disgust: a randomized trial to reduce high-calorie food appeal through implicit priming

Background: In our increasingly obesogenic environment, in which high-calorie convenience foods are readily available, food choices can drastically affect weight and overall health: Learned food preferences, which are developed through repeated pairings with positively and negatively valenced stimuli, can contribute to obesity susceptibility if positive attitudes toward high-calorie foods are developed. Thus, the modification of automatic associations with food may be a viable strategy to promote healthier eating behaviors. Objective: In this study, we investigated the ability of an implicit priming (IP) intervention to alter responses to visual food cues by using an evaluative conditioning approach. The main objective was to implicitly (i.e., below conscious perception) associate disgust with high-calorie foods with the aim of reducing liking of these foods. Design: Participants were randomly assigned to active or control IP. In active IP (n = 22), high-calorie food images were implicitly primed with negatively valenced images, and low-calorie food images were implicitly primed with positively valenced images. In control IP (n = 20), all food images were primed with neutral images of fixation crosses. Food images were rated on the desire to eat immediately before and after EP. Results: A significant main effect of calorie (high compared with low; P < 0.001) and a significant calorie-by-group (active compared with control) interaction (P = 0.025) were observed. Post hoc tests identified a significantly greater high-calorie rating decline after active IP than after control IP (P = 0.036). Furthermore, there was significantly greater change in high-calorie ratings than in low-calorie ratings in the active group (P = 0.001). Active IP effects extended to high-calorie foods not specifically included in the intervention, which suggested an effect generalization. Moreover, a greater change in high-calorie ratings than in low-calorie ratings persisted 3-5 d after active IP (P < 0.007), which suggested lasting effects. Conclusion: This study provides initial evidence that IP can be used to alter high-calorie food preferences, which could promote healthier eating habits. This trial was registered at clinicaltrials.gov as NCT02347527.