Eating Behavior-Choice or Reconstruction of Past Experience? A Randomized Clinical Trial of Changing Eating Intentions of Healthy Adults Through Hypnotic Suggestions

Recent meta-analyses have shown that psychological interventions have a small to medium effect on weight loss. We propose here a different approach to changing eating intentions. According to the Free Will literature, people decide to act before they acknowledge it, and they decide based on the reconstruction of previous experiences. The action can thus be inhibited immediately (max 100 ms) after awareness. We wanted to test if intervention based on this model, using hypnotic suggestions, can effectively change the intentions of eating. This study aims to identify which format of hypnotic suggestion can be more effective in changing eating intentions regarding high-calorie foods. Therefore, 88 healthy adult participants randomized in four groups received one session of hypnotic induction and suggestions or placebo. We measured the eating intentions through a computer task in which participants could choose pictures of low and high caloric food before, during, and after hypnosis. For the within-subject effect, results showed that two types of hypnotic suggestions significantly impacted the intentions of eating on high-calorie foods with large-effect, namely Cognitive Rehearsal (d = 0.81, p < .001) and Memory Substitution (d = 0.82,p < .001). After controlling for pretest ratings, we found a significant between-effect: the Cognitive Rehearsal group differed significantly from the Control in terms of intentions of eating (d = 0.85, p < .05). We conclude that hypnosis with Cognitive Rehearsal suggestions can help to positively impact the intentions of eating.