Children who eat more ultra-processed foods show stronger brain reward responses to food images, which link directly to later body fat increases. Published in JAMA Network Open, the BrainChild study surveyed children aged seven to 10 to investigate how convenience foods alter neurological responses over time.
BrainChild Study Tracks 46 Children Over One Year
The research followed 46 children between the ages of seven and 10 who started the observation period at a healthy weight. Researchers gathered baseline data by performing magnetic resonance imaging brain scans while the participants viewed photographs of appetizing foods such as cookies and French fries.
Alongside the scans, the study recorded dietary habits, body mass index, body fat percentage, and waist circumference. One year later, investigators measured the same physical metrics again to track changes in body composition.
Ultra-processed foods—manufactured items like packaged bread, breakfast cereals, and instant soups designed to be shelf-stable and highly palatable—account for roughly 67% of daily calories for children in the United States. Kathleen A. Page, professor of medicine and pediatrics at the Keck School of Medicine of USC, noted the vulnerability of young minds during this developmental phase.
Children’s brains are still developing, habits are still forming and food preferences are still being made. It’s an important period where the brain is very sensitive to food and the food environment.
Kathleen A. Page, MD, professor of medicine and pediatrics and co-chief of the Division of Endocrinology and Diabetes at the Keck School of Medicine of USC
Dorsal Striatum Activation Links Diet to Body Fat
Children reporting higher daily intakes of ultra-processed foods displayed stronger neural activity in the dorsal striatum when looking at food pictures. This specific brain region governs reward processing and motivation. Those elevated neural responses correlated with measurable increases in body mass index and body fat percentage a year later.
When investigators adjusted their statistical models to account for differences in dorsal striatum responses, the association between processed food consumption and subsequent weight gain weakened by 31% for body mass index and 44% for body fat percentage.
This statistical change indicates that altered brain reward sensitivity helps explain how these foods drive body composition changes over time. Page emphasized the implications of the findings for understanding neurobiological mechanisms.
This study goes beyond just understanding that UPFs affect weight gain. It actually gives us insight into the neurobiological underpinnings by which these foods may be linked to body composition over time.
Kathleen A. Page, MD, professor of medicine and pediatrics and co-chief of the Division of Endocrinology and Diabetes at the Keck School of Medicine of USC
Caloric Intake Adjustments Erase Brain Injury Associations
That adult-focused paper found modest associations between high daily servings of processed items and vascular brain injury rates, alongside a tie to obesity. When researchers redefined dietary exposure as a percentage of total energy intake rather than raw servings per day, or when they adjusted for total caloric intake, the statistical associations with brain injury disappeared entirely.
Testing Cause and Effect in Future Trials
Because the pediatric investigation was observational, it could not definitively prove whether consuming ultra-processed foods directly causes changes in brain activity or weight gain. To test cause and effect, Page plans to launch an intervention trial supplying children who regularly eat these foods with more minimally processed alternatives.
Modifying the food environment to expand access to minimally processed alternatives forms part of any permanent solution.