Childhood junk food may rewire the brain for life

Scientists at APC Microbiome, a leading research center based at UCC, discovered that unhealthy diets during early life can alter how the brain controls appetite and feeding. These changes persisted even after the unhealthy diet ended and body weight returned to normal.

Today’s children are surrounded by highly processed foods that are heavily marketed and easy to access. Sugary and fatty foods have become common at birthday parties, school events, sports activities, and even as rewards for good behavior. Researchers say this constant exposure may shape food preferences from an early age and encourage eating habits that continue into adulthood.

Childhood Diets and Long-Term Brain Changes

The study, published in Nature Communications, found that early exposure to calorie-dense, nutrient-poor foods can leave lasting effects on feeding behavior. Researchers used a preclinical mouse model and found that animals exposed to a high-fat, high-sugar diet early in life showed persistent changes in eating behavior as adults.

The team linked these behavioral effects to disruptions in the hypothalamus, a brain region responsible for regulating appetite and energy balance.

The research also explored whether targeting the gut microbiome could help counter these effects. Scientists tested a beneficial bacterial strain (Bifidobacterium longum APC1472) along with prebiotic fibers (fructo-oligosaccharides (FOS) and galacto-oligosaccharides (GOS), naturally present in foods such as onions, garlic, leeks, asparagus and bananas, and widely available in fortified foods and prebiotic supplements).

According to the findings, both approaches showed potential benefits when given throughout life.

Gut Bacteria May Help Restore Healthy Eating Patterns

“Our findings show that what we eat early in life really matters.” said Dr. Cristina Cuesta-Martí, first author of the study. “Early dietary exposure may leave hidden, long-term effects on feeding behavior that are not immediately visible through weight alone.”

Researchers found that unhealthy diets early in life disrupted brain pathways linked to feeding behavior, with effects continuing into adulthood. The findings suggest this could raise the risk of obesity later in life.

Importantly, scientists found that modifying the gut microbiota helped reduce these long-term effects. The probiotic strain Bifidobacterium longum APC1472 significantly improved feeding behavior while causing only minor changes to the overall microbiome, suggesting a highly targeted effect. Meanwhile, the prebiotic combination (FOS+GOS) produced broader changes across the gut microbiome.

Microbiome Research Opens New Possibilities

“Crucially, our findings show that targeting the gut microbiota can mitigate the long-term effects of an unhealthy early-life diet on later feeding behavior. Supporting the gut microbiota from birth helps maintain healthier food-related behaviors into later life.” said Dr. Harriet Schellekens, lead investigator of the study.

Professor John F. Cryan, Vice President for Research & Innovation at UCC and collaborator on the project, said: “Studies like this exemplify how fundamental research can lead to potential innovative solutions for major societal challenges. By revealing how early-life diet shapes brain pathways involved in the regulation of feeding, this work opens new opportunities for microbiota-based interventions.”

The UCC-led study involved collaborators from the University of Seville (Spain), University of Gothenburg (Sweden), and Teagasc Food Research Centre (Fermoy, Ireland). Funding came from Research Ireland, a Government of Ireland Postgraduate Scholarship, and a research award from the Biostime Institute for Nutrition & Care.