Children who consume more ultra-processed foods show heightened activity in the brain's reward system when viewing pictures of appetizing foods, according to a study published in JAMA Network Open. Researchers led by Kathleen A. Page, MD, a professor of medicine and pediatrics at the Keck School of Medicine of USC, found that this stronger brain response was associated with greater increases in body fat over the following year.
The team studied 46 children ages 7 to 10 enrolled in the BrainChild study, which examines factors contributing to diabetes and obesity. All participants had healthy weights at the start. Children underwent brain scans while viewing pictures of appealing foods like cookies and French fries. Researchers also collected dietary information and measured body mass index, body fat percentage, and waist circumference. After one year, they repeated these measurements.
Brain scans revealed that children consuming larger amounts of ultra-processed foods showed greater activity in the dorsal striatum, a brain region that regulates reward and motivation. Children with stronger responses in this area also experienced greater increases in BMI and body fat percentage over the next year.
Ultra-processed foods include breakfast cereals, packaged bread, and instant soups. These products account for approximately 67% of calories consumed by children in the United States.
When researchers adjusted their analysis to account for brain activity in the dorsal striatum, the relationship between ultra-processed food intake and BMI weakened by 31%. The association with body fat percentage decreased by 44%. This suggests the brain's reward response may partially explain the link between ultra-processed foods and weight gain.
Page cautioned that the study was observational and cannot establish whether eating ultra-processed foods directly causes heightened brain activity or weight gain. She noted that changing the food environment to make healthier options more accessible and affordable is essential, as ultra-processed products are often inexpensive and convenient. Page plans to conduct a future intervention study providing children who regularly consume ultra-processed foods with more minimally processed alternatives to examine whether dietary changes affect brain responses to food images and weight gain.