Food processing and emotion regulation in vegetarians and omnivores: An event-related potential investigation

The present study investigated cognitive reappraisal during exposure to vegetarian and nonvegetarian food cues in food-deprived vegetarian and omnivore participants. In particular, we were interested in clarifying the motivational meaning of the foods that vegetarians avoid, as revealed by self-reported food craving, valence, and arousal, as well as by ERP measures of neural processing during passive viewing and emotional regulation. Twenty-four vegetarians and twenty-one omnivores were instructed to either passively look at the pictures (Watch) or to change the appetitive value of the food (Increase or Decrease). In vegetarians, meat and fish dishes elicited lower desire to eat, pleasantness, and arousal during each condition as compared to both omnivores and vegetarian food. In contrast with the subjective data, no group differences were observed in any of the ERP measures, suggesting that similar neural processing of food-cues occurred in vegetarians and omnivores both during passive viewing and cognitive reappraisal. Concerning the late ERP effects during cognitive reappraisal, we found an enhancement of the P300 and LPP amplitudes during the Increase and the Decrease as compared to the Watch condition and a reduction of the SW amplitude in the Decrease as compared to Watch condition. These results suggest that in a food deprivation condition it is difficult to reduce the appetitive value of food stimuli, as this cognitive strategy appears to require greater effort and a longer time to be implemented with respect to up-regulation. Overall, our findings suggest that, in vegetarians, aversion towards nonvegetarian food prevails at the subjective level and is consistent with their personal beliefs. In contrast, at the neural level, the intrinsic motivational salience of this type of food is preserved.