The neural pathways of change: an fMRI study of the effects of behavioral change suggestions on value-based dietary...

Resolving the ambivalence between immediate cravings and long-term consequences is a key target of communication-based interventions toward behavioral change, such as motivational interviewing. Here, we aimed at understanding how this ambivalence between changing and sustaining unhealthy eating habits influences food valuation and its neural mechanism.

Eighty-five participants with varying body mass indices and food addiction-like symptoms underwent a motivational interviewing session during which they formulated personal reasons for (i.e., change talk) and against (i.e., sustain talk) changing their current eating habits. One week later, they listened to their statements when rating how much they wanted to eat various food items for real at the end of the experiment while their brain activation was measured with functional magnetic resonance imaging.

Food choices were healthier when participants had listened to their change talk statements, and more based on taste following sustain talk statements. This effect was stronger in participants with a BMI ≥ 25 kg/m², particularly among those with more food addiction-like symptoms displayed in their everyday life eating habits. On the neural level, participants with a BMI ≥ 25 kg/m² also showed stronger functional connectivity between the ventromedial and dorsolateral prefrontal cortex at the time of food choice following a change compared to a sustain talk statement. On the contrary, participants with a BMI < 30 kg/m² displayed stronger neural craving responses when making their food choices following sustain talk. Moreover, after change talk, among participants with a BMI < 30 kg/m², those with higher BMI displayed stronger neural craving responses during healthy food wanting, and lower responses during tasty food wanting.

These findings indicate that shifting between changing and sustaining unhealthy eating habits biases food valuation and its encoding in neural pathways linked to valuation, cognitive control, and craving as a function of weight status.

This study was pre-registered (https:/clinicaltrials.gov/study/NCT05101863).