Ultra-processed foods are linked to measurable declines in attention and focus, even among people who otherwise follow healthy diets, according to a new study from Australian and international researchers.
The research, published in Alzheimer’s & Dementia: Diagnosis, Assessment & Disease Monitoring, analyzed dietary habits and cognitive performance in over 2,100 dementia-free Australian adults aged middle-aged and older. Participants derived about 41% of their daily energy from ultra-processed foods, closely matching the national average of 42%.
For every 10% increase in ultra-processed food consumption, researchers observed a distinct and measurable drop in attention span and processing speed — equivalent to adding a standard packet of chips to a daily diet. These effects persisted regardless of overall diet quality, including among those adhering to Mediterranean-style eating patterns.
Lead author Dr Barbara Cardoso from Monash University said the findings underscore that food processing itself, not just nutrient content, plays a critical role in cognitive health. Ultra-processing often destroys food’s natural structure and introduces additives like emulsifiers and artificial colourants that may harm brain function.
While the study did not find a direct link between ultra-processed foods and memory loss, it identified associations with dementia risk factors such as high blood pressure and obesity. Attention, researchers note, is foundational for learning, decision-making, and complex mental operations, making early declines a potential indicator of broader cognitive vulnerability.
The results align with earlier research, including a 2022 study in Neurology that found replacing 10% of ultra-processed foods with minimally processed alternatives could reduce dementia risk by 19% over a decade.
Ultra-processed foods impair focus even in healthy eaters
The study’s most striking finding was that the negative impact on attention occurred irrespective of overall diet quality. Participants who followed generally healthy eating patterns still showed reduced cognitive performance when their intake of ultra-processed foods increased.
For more on this story, see Foods to Avoid: 4 You Should Cut Now.
This challenges the assumption that nutrient-rich diets can fully offset the harms of processed foods. Instead, it suggests the degree of food processing may be as important as the nutritional content when assessing brain health risks.
How processing affects the brain remains under study
Researchers hypothesize that industrial processing alters food in ways that could affect neurological function — by removing beneficial components and adding synthetic substances not found in home pantries. However, the precise biological mechanisms connecting ultra-processed foods to attention deficits are still being investigated.
They emphasized that while the observed effects were measurable and consistent, they were not dramatic in isolation. Yet, because attention underpins so many cognitive functions, gradual erosion could have meaningful long-term consequences.
This follows our earlier report, Diabetes & Healthy Living: Treatment Link 2.
Global dietary trends raise concern
With ultra-processed foods making up over 40% of daily energy intake in Australia — a figure reflective of broader global patterns — the findings suggest a widespread, modifiable risk factor for cognitive decline. The study adds to growing evidence that food manufacturing practices may have underappreciated effects on long-term brain health.
What counts as ultra-processed food?
Ultra-processed foods are industrial formulations typically containing little or no wholefood. Examples include soft drinks, packaged chips, sweets, reconstituted meats, and ready-to-heat meals. They often contain additives like preservatives, emulsifiers, and artificial flavours not used in home cooking.
Can a healthy diet protect against the effects of ultra-processed foods?
No. The study found that even individuals following Mediterranean-style diets experienced declines in focus when they increased their intake of ultra-processed foods, indicating that diet quality does not neutralize the impact of food processing.
Is there a direct link between ultra-processed foods and dementia?
The study did not establish a direct causal link to dementia or memory loss. However, it found associations with known risk factors like high blood pressure and obesity, and supports prior research suggesting dietary changes could reduce dementia risk.
