Children who ate more ultra-processed food showed stronger reward activity when viewing junk-food images, a response associated with greater increases in body fat and BMI over the following year.
Ultra-processed foods may be doing more than filling children up. According to research published in JAMA Network Open, the sight of cookies, crisps or fries can spark a stronger reward response in the brains of children who eat more ultra-processed products, and that heightened reaction appears to be linked with greater weight gain and more body fat over time. The study adds to a growing body of evidence suggesting that heavily processed diets may influence not only children’s waistlines but also the brain circuits involved in motivation and reward.
The researchers studied 46 children who began the project at a healthy weight, using MRI scans while they looked at images of ultra-processed foods. They also tracked diet, body mass index, waist size and body fat. Children with higher intakes of ultra-processed food showed stronger activity in the dorsal striatum, a brain region tied to reward and habit formation. One year later, that same heightened brain response was associated with increases in BMI and body fat, suggesting that food cues may help shape eating patterns in ways that persist beyond the immediate moment.
This fits with earlier research showing that ultra-processed foods may affect children’s development at a very young age. A study reported by Powers Health and published in The American Journal of Clinical Nutrition found that children exposed to more ultra-processed foods in infancy and early childhood had measurable differences in brain structure by age 6, even without clear changes in cognitive performance. Separately, a study published in August in the same journal found that greater cumulative intake of ultra-processed foods from infancy through early childhood was linked with smaller volumes in several brain regions involved in reward, emotion and motivation.
Other recent research suggests the effects of junk food may begin even earlier and may be harder to reverse than many parents realise. ScienceDaily reported in May on work from University College Cork showing that high-fat, high-sugar diets in early life could rewire feeding behaviour and alter appetite-control regions in the brain, with some benefits seen when prebiotic fibres and gut-friendly bacteria were added. Earlier this year, Drugs.com also reported on a study linking higher ultra-processed food intake in preschoolers with emotional and behavioural problems, including anxiety, aggression and hyperactivity.
The new JAMA Network Open study cannot prove that ultra-processed foods directly cause weight gain through brain changes, because it was observational. But the findings strengthen the case for limiting heavily processed foods in children’s diets and increasing access to healthier meals and snacks. Kathleen Page of the Keck School of Medicine of USC said in a news release that changing the food environment is an important part of the solution, and she said her team plans to test whether improving the diet can also change children’s brain responses to food cues.
Disclaimer: This content is for informational purposes only and is not intended to be a substitute for professional medical judgment, advice, diagnosis, or treatment.
