Ultra-Processed Foods Linked to Reward-System Response in Children
14:44 5 November, 2026Children who consumed more calories from ultra-processed foods showed a stronger response in a specific brain region when viewing images of appetizing foods. This response was associated with a subsequent increase in body fat. The study, conducted by researchers at the University of Southern California, was published in the journal JAMA Network Open.
The analysis included 46 children aged seven to ten with normal body weight. The researchers assessed their diets, body mass index (BMI), waist circumference, and body composition. During functional MRI scans, participants were shown images of appealing foods, such as cookies and French fries, interspersed with pictures of non-food items.
On average, ultra-processed foods accounted for approximately 68% of the children's total calorie intake. A higher proportion of these foods in the diet was associated with an increased response in the dorsal striatum, a brain region involved in motivation, learning, and reward processing. No statistically significant association was found for the ventral striatum.
One year later, the researchers reassessed the children's physical measurements. A stronger initial response in the dorsal striatum was associated with greater increases in BMI and body fat percentage. The initial proportion of ultra-processed foods in the diet was also associated with an increase in waist circumference.
After the brain response was included in the statistical model, the associations between diet and changes in BMI and body fat percentage became weaker. The authors suggest that sensitivity to food cues may be one of the mechanisms linking dietary habits to subsequent increases in body fat.