A massive new study of nearly 30,000 adults has found that people who eat more ultra-processed foods — think frozen pizzas, packaged snacks and processed meats — may have structural differences in key brain areas linked to hunger, impulse control and reward. These changes could make it harder to regulate eating behavior, potentially fueling a cycle of overeating.
“Our findings suggest that higher consumption of ultra-processed foods is associated with differences in the brain,” said Arsène Kanyamibwa, a researcher at the University of Helsinki and shared first author of the study. “These associations could be linked to behavioral patterns such as overeating, though causal relationships cannot be confirmed by our study.”
Using brain scans from the UK Biobank, the researchers found regions with lower cell density — potential signs of degeneration — as well as areas with increased cell density, which may reflect inflammation. These patterns appeared even after accounting for body weight and inflammation alone, suggesting food additives like emulsifiers could play a role. More research is needed to understand the mechanisms.
Importantly, not all processed foods are harmful.
“Processed foods of plant origin, such as frozen vegetables, can be recommended,” Kanyamibwa said. “Another good example of the benefits of processing is the pasteurisation of milk. In contrast, foods high in chemically modified ingredients and additives, such as processed meat products, are problematic.”
The study was published in npj Metabolic Health and Disease and conducted by researchers from the University of Helsinki and McGill University’s Montréal Neurological Institute. It used data from the UK Biobank and was supported by all three institutions.