Reproducibility assessment of brain responses to visual food stimuli in adults with overweight and obesity

Objective The brain's reward system influences ingestive behavior and subsequently obesity risk. Functional magnetic resonance imaging (fMRI) is a common method for investigating brain reward function. This study sought to assess the reproducibility of fasting‐state brain responses to visual food stimuli using BOLD fMRI. Methods A priori brain regions of interest included bilateral insula, amygdala, orbitofrontal cortex, caudate, and putamen. Fasting‐state fMRI and appetite assessments were completed by 28 women (n = 16) and men (n = 12) with overweight or obesity on 2 days. Reproducibility was assessed by comparing mean fasting‐state brain responses and measuring test‐retest reliability of these responses on the two testing days. Results Mean fasting‐state brain responses on day 2 were reduced compared with day 1 in the left insula and right amygdala, but mean day 1 and day 2 responses were not different in the other regions of interest. With the exception of the left orbitofrontal cortex response (fair reliability), test‐retest reliabilities of brain responses were poor or unreliable. Conclusions fMRI‐measured responses to visual food cues in adults with overweight or obesity show relatively good mean‐level reproducibility but considerable within‐subject variability. Poor test‐retest reliability reduces the likelihood of observing true correlations and increases the necessary sample sizes for studies.