Children who consume high amounts of ultra-processed foods show significantly stronger brain activity in reward centers when exposed to food cues, according to a new study published in JAMA Network Open. This heightened neurological response may help explain why these products are associated with weight gain and increased body fat over time.
The investigation, supported in part by the National Institutes of Health, combined magnetic resonance imaging (MRI), dietary assessments, and body composition measurements. Researchers found that the brain’s reaction to appetizing food images was more intense in children with diets heavy in these manufactured products. This biological mechanism provides a potential explanation for the long-observed link between ultra-processed diets and obesity.
Brain Scans Reveal Reward System Sensitivity
The study involved 46 children aged seven to ten who were enrolled in the ongoing BrainChild study. All participants had a healthy weight at the start of the research, allowing scientists to observe early warning signs before excess weight developed. The team conducted brain scans while the children viewed pictures of appealing foods, such as cookies and French fries.
Results showed that children who ate more ultra-processed foods had greater activity in the dorsal striatum. This brain region regulates reward and motivation, playing a key role in how people respond to desirable foods. Importantly, those with stronger responses in this area experienced greater increases in body mass index (BMI) and body fat percentage over the following year.
When researchers adjusted their analysis to account for this brain activity, the statistical link between ultra-processed food intake and BMI weakened by 31 percent. The association with body fat percentage decreased by 44 percent. These reductions suggest that the brain’s reward response helps explain part of the relationship between diet and changes in body composition.
Widespread Consumption and Developmental Risks
Ultra-processed foods include many everyday items such as breakfast cereals, packaged bread, and instant soups. These products are manufactured to be appealing, convenient, and shelf-stable, often containing artificial sweeteners, coloring agents, and other ingredients rarely used in home cooking. They account for approximately 67 percent of the calories consumed by children in the United States.
Previous research has associated high consumption of these foods with obesity, type 2 diabetes, and cardiovascular disease. However, the biological processes behind these connections remained unclear. This new investigation offers insight into the neurobiological underpinnings of these health outcomes.
Kathleen A. Page, MD, the study’s senior author and professor of medicine and pediatrics at the Keck School of Medicine of USC, emphasized the importance of this developmental window. “Children’s brains are still developing, habits are still forming and food preferences are still being made,” Page said. “It’s an important period where the brain is very sensitive to food and the food environment.”
Page noted that intervening early could make a real difference in long-term health outcomes. The study highlights that children’s brains are particularly sensitive to the food environment during these formative years, making the impact of highly engineered foods potentially more pronounced than in adults.
Limitations and Future Directions
The researchers caution that improving children’s diets cannot rely solely on individual families. Ultra-processed products are often inexpensive, widely available, and easy to prepare, making them practical choices for households facing financial or time constraints. Page stated that changing the food environment to help people access healthier, more minimally processed foods is an important part of the solution.
Because the study was observational, it cannot determine whether eating ultra-processed foods directly causes heightened brain activity or increases in weight. The findings establish relationships between these factors, but additional research is needed to determine causality. Page hopes to address this question in a future intervention study where children would be provided with more minimally processed alternatives to see if dietary changes affect brain responses and weight gain.
The BrainChild study will continue tracking participants as they move through puberty and into early adulthood. By monitoring brain development, body composition, dietary patterns, and general health over time, researchers hope to gain a clearer picture of how childhood nutrition influences long-term health.
Source: ScienceDaily
