Childhood junk food can rewire brain for life: Study

Consuming large amounts of junk food early in life may cause lasting changes in the brain, even if a person later adopts a healthier diet. Scientists discovered that diets high in fat and sugar altered eating habits and affected brain regions responsible for controlling appetite. However, some beneficial gut bacteria and prebiotic fibres showed potential in reversing part of these effects. According to a new study from University College Cork (UCC), Children who regularly eat high-fat, high-sugar foods may experience lasting changes in the brain that continue long after their diets improve.

Researchers also found that beneficial gut bacteria and prebiotic fibres could help reduce some of these long-term effects and support healthier eating behaviours later in life.
Scientists at APC Microbiome, a leading research centre 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 behaviour. Researchers say this constant exposure may shape food preferences from an early age and encourage eating habits that continue into adulthood. The study, which was published in Nature Communications, found that early exposure to calorie-dense, nutrient-poor foods can leave lasting effects on feeding behaviour. 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 behaviour as adults. The team linked these behavioural effects to disruptions in the hypothalamus, a brain region responsible for regulating appetite and energy balance.

Also read: Trying To Cut Down On Junk Food? Here Are 5 Healthy Tips That Make Cravings Easier To Manage

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 fibres (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-Marti, first author of the study. "Early dietary exposure may leave hidden, long-term effects on feeding behaviour that are not immediately visible through weight alone," added Dr Cristina Cuesta-Marti. Researchers found that unhealthy diets early in life disrupted brain pathways linked to feeding behaviour, with effects continuing into adulthood. The findings suggest this could raise the risk of obesity later in life.

Also read: How To Resist Unhealthy Food Cravings? 5 Easy Tips To Avoid Junk Food

Scientists also found that modifying the gut microbiota helped reduce these long-term effects. The probiotic strain Bifidobacterium longum APC1472 significantly improved feeding behaviour 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.