How Ultra-Processed Foods Affect Children's Brains: Study Links Brain Activity to Weight Gain

The study involved 46 children aged seven to ten who were at a healthy weight at the start of the observation period. The researchers performed brain MRI scans while the children viewed images of appealing foods, such as cookies and French fries. They also collected information on the participants' diets, body mass index (BMI), waist circumference and body fat percentage. The measurements were repeated one year later.

The results showed that children who consumed more ultra-processed foods had greater activation in the dorsal striatum, a brain region involved in reward processing and motivation. A stronger response in this region to food images was also associated with increases in BMI and body fat percentage over the following year.

By the end of the observation period, children who consumed these foods more frequently had, on average, higher BMIs, greater body fat percentages and larger waist circumferences. When the researchers accounted for differences in brain responses to food images, the association between ultra-processed food consumption and increases in BMI weakened by 31%, while the association with body fat percentage weakened by 44%. This suggests that differences in the brain's response to food may partly explain the link between diet and changes in body composition.

Ultra-processed foods include certain breakfast cereals, commercially packaged bread and instant soups. They often contain ingredients not typically used in home cooking. Estimates suggest that these foods account for approximately 67% of children's daily calorie intake in the United States.

Kathleen Page, the study's senior author and a professor of medicine and pediatrics at the Keck School of Medicine of the University of Southern California, emphasized that the brain, eating habits and food preferences continue to develop throughout childhood. For this reason, she said, early intervention could be particularly important.