Ultra-Processed Foods Linked to Behavioural Issues in Preschoolers, Study Finds

A new study highlights a troubling connection between ultra-processed foods in early childhood and later behavioural problems. Nearly half of Canadian preschoolers' daily calories now come from these foods. Researchers warn that early eating habits could shape mental health and behaviour for years to come.

The study found that 48% of Canadian preschoolers' energy intake came from ultra-processed foods (UPFs). The most common sources were sweets and desserts (12.5%), breads and cereals (11.9%), animal-based products (7.9%), and ready-to-eat or reheat mixed dishes (6.1%).

Higher consumption of breads, cereals, and pre-prepared meals at age three was linked to more internalising behaviours, such as anxiety or withdrawal. Similarly, children who drank more artificially sweetened or sugary beverages showed higher internalising and overall behavioural scores.

By age five, every 10% increase in calories from UPFs corresponded to more internalising and externalising behaviours, including aggression and hyperactivity. The study also noted that environmental factors—like long commutes or limited access to fresh food markets—played a role in UPF consumption.

Over the past five years (2021–2026), UPF intake among preschoolers rose by 12% in the US, 8% in the UK, and 10% in Australia. In Canada, however, consumption remained stable at around 60% of daily energy intake, according to WHO and national dietary surveys.

The findings suggest that early dietary patterns have lasting effects on children's behaviour. Establishing consistent, healthy eating habits from a young age may help reduce emotional and behavioural difficulties later. The study encourages a broader approach to tackling UPF consumption, rather than focusing blame on individual parents.