Junk Food in Childhood May Cause Lasting Brain Changes Even After Healthy Diet, Study Finds

A new study reveals how a high-fat, sugary childhood diet permanently alters the brain's appetite control, even after diet improves. Learn how gut health can help.

A new study from University College Cork has found that consuming excessive amounts of fatty and sugary food during childhood can lead to long-term changes in the brain, even after switching to a healthier diet later in life. The research was conducted by scientists at APC Microbiome Ireland, a top microbiome research center located at UCC.

The findings, published in the journal Nature Communications, suggest that poor eating habits in early life may have a lasting effect on how the brain regulates appetite and eating behaviours. The study showed that these effects persisted even when body weight returned to normal levels.

Modern Eating

Researchers explained that children today are frequently exposed to highly processed foods that are inexpensive, widely available, and heavily advertised. Foods rich in sugar and fat are commonly found at parties, school events, sports activities, and are often used as rewards. Scientists believe that this repeated exposure from an early age can influence food preferences and lead to unhealthy habits that continue into adulthood.

Using a preclinical mouse model, the research team discovered that animals fed a high-fat, high-sugar diet during their early development later exhibited lasting changes in their eating behaviours as adults. The study linked these changes to issues in the hypothalamus, the part of the brain responsible for controlling hunger and maintaining energy balance.

Gut Connection

The scientists also examined whether improving gut health could reduce these long-term effects. They tested a beneficial bacteria strain called “Bifidobacterium longum APC1472” along with prebiotic fibres known as FOS and GOS. These fibres naturally occur in foods like onions, garlic, leeks, asparagus, and bananas, and are also added to some fortified foods and supplements.

According to the researchers, both treatments showed promising results when used throughout life. Dr Cristina Cuesta-Martí, the study’s first author, stated that the findings show that diet during childhood plays a major role in shaping future eating behaviours, even when the effects are not visible through changes in body weight alone.

Future Solutions

The team found that improving the gut microbiota helped reduce the long-term effects caused by unhealthy childhood diets. The probiotic strain improved feeding behaviour while only slightly altering the broader gut microbiome, suggesting it works in a targeted way. Meanwhile, the prebiotic fibre combination caused more widespread changes in gut bacteria.

The researchers say that supporting healthy gut bacteria from birth could encourage healthier eating patterns later in life. The study opens the door to new microbiome-based approaches that may help address obesity and other diet-related health issues in the future.