Ultra-processed food quietly harms your attention
You can eat a generally healthy diet and still suffer cognitively if ultra-processed foods are part of the picture.
Ultra-processed foods include products that have undergone heavy industrial processing: crisps, ready meals, sweetened breakfast cereals, soft drinks. They are typically low in fibre and high in additives. People who ate more of them scored worse on attention tests and showed slower information processing. That applied even to participants who were otherwise eating healthily. The researchers also found that higher consumption was linked to more risk factors for dementia.
This is an association study: the researchers found a correlation, not a proven causal relationship. People who eat a lot of ultra-processed food may differ in other lifestyle habits too. Even so, the association held after accounting for overall diet quality, which makes it harder to dismiss.
How ultra-processed food may affect the brain
Several mechanisms are plausible. Ultra-processed foods cause larger blood sugar fluctuations, which affect short-term brain function. They are also low in brain-supportive nutrients such as omega-3 fatty acids and antioxidants. And the combination of additives and preservatives can alter the gut microbiome. Through the gut-brain axis, the two-way signalling between the gut and the brain, shifts in microbiome composition may influence cognition and mood.
For longevity, this matters because cognitive decline is one of the most impactful forms of aging. If dietary patterns already influence processing speed and dementia risk in midlife, that is a concrete target for prevention.
What this means in practice
The study does not justify dramatic conclusions. One portion of crisps a day does not cause dementia. But the research adds to a growing body of evidence that ultra-processed foods, even in moderate amounts, have measurable effects on cognitive function. Paying attention to the degree of food processing, alongside familiar criteria like calorie and fibre content, looks increasingly worthwhile based on this kind of evidence.