Effectiveness of a Smartphone-Delivered Approach-Avoidance Intervention in Dietary Behavior - A Randomized Controlled Trial

Background Given the therapeutic potential of Approach-Avoidance interventions (AAIs) in the alcohol domain, research has increasingly applied them to the food domain. In AAIs, harmful stimuli are avoided while healthy ones are approached, for example by respectively moving a phone away from or towards oneself. Methods We administered a phone-based AAI six times over two weeks to 156 participants in a pre-registered randomized-controlled trial to reduce intake of six “decrease-foods” and increase intake of six “increase-foods”, selected according to each participant’s individual dietary goals. The control group received a placebo task in which all stimuli were equally often approached and avoided. Food craving and intake were the outcomes, measured daily during the training period, four days before and after, and once during a follow-up one month after training. Per-food approach bias was recorded before and after training, and at follow-up. Results Compared to placebo, active training reduced the level of decrease-food craving without affecting how often craving occurred. Restrained eaters and those with low past dietary success showed the strongest craving strength reduction. Active training also reduced approach bias for decrease-foods. We found no intervention effects on increase-foods on any outcome. There were no interpretable training effects for food intake and no changes were maintained at follow-up. Conclusions We find support for the use of AAI against food cravings for goal-incongruent foods, especially for those who struggle with their diet. It remains to future research how this can be effectively translated into reduced food intake. Trial registration This study was registered in the German Clinical Trials Register, ID DRKS00030780.