If you love chips, scientists don’t have the best news for you
Ultra-processed foods like chips, soda, and frozen ready meals make up about 40% of the diet in Western countries. A new study involving more than two thousand people discovered an unexpected link: the more such food in a person’s diet, the worse the brain performs on attention tasks. If a bag of chips sits next to your salad, not even the healthiest Mediterranean diet can save you.
Study on the effects of chips and soda on the brain
A team of scientists analyzed data from 2,192 Australians aged 40 to 70 who had no dementia diagnosis. Participants filled out a detailed nutrition questionnaire and completed four cognitive tests measuring attention and memory. The results were published in April 2026 in the journal Alzheimer’s & Dementia: Diagnosis, Assessment & Disease Monitoring, part of the Alzheimer’s Association system.
An important note: this is an observational, not an experimental study. It shows correlation — a consistent statistical relationship between two phenomena — but does not prove that ultra-processed food directly causes cognitive decline. Nevertheless, the patterns found are striking enough for scientists to continue investigating the mechanisms.
How even one bag of chips a day can be harmful
On average across the group, ultra-processed products accounted for about 41% of daily caloric intake, which practically matches the Australian national average. Younger participants and men had a noticeably higher share.
The key finding: for every 10% increase in the share of ultra-processed food in total caloric intake, researchers recorded a measurable decline in visual attention and information processing speed — approximately 0.05 points on standardized tests. At the same time, dementia risk scores increased by about 0.24 points per the same 10%.
To put the scale in perspective: a 10-percent increase is roughly equivalent to one standard bag of chips or a can of soda added to the daily diet. It might seem trivial. But on cognitive tests, it already makes a noticeable difference.
Dementia risk was assessed using the CAIDE scale — a validated tool that predicts the likelihood of developing dementia within the next 20 years based on vascular risk factors: blood pressure, cholesterol levels, body weight, physical activity, and age.
Healthy eating doesn’t compensate for the harm of chips and soda
One of the most unexpected results: following a Mediterranean diet did not weaken the negative association between ultra-processed food and attention. In other words, if a person ate plenty of vegetables, fish, olive oil, and whole grains but regularly snacked on chips and drank soda, their cognitive test results were still worse.
Even with a healthy diet, ultra-processed snacks can reduce attention scores
The study authors suggest that the issue is not just a lack of beneficial nutrients but the industrial processing itself. Industrial processing destroys the natural structure of food and introduces substances that are absent in natural products: artificial additives, emulsifiers, colorants, flavorings, and processing chemicals.
Interestingly, the study found no link between ultra-processed food and memory. Only attention was affected — the ability to focus and quickly process visual information. But attention is considered the foundation for more complex cognitive operations: learning, problem-solving, and decision-making.
What counts as ultra-processed food
The term ultra-processed foods may sound vague, but it has a clear scientific framework. The study used the NOVA classification, developed by Brazilian scientists and adopted in dozens of countries. It divides all food into four groups — not by nutritional content, but by the degree of industrial processing.
Ultra-processed foods are products that cannot be made in a home kitchen using ordinary methods:
- carbonated drinks and energy drinks;
- packaged chips and snacks;
- ready-made frozen meals;
- sausages and hot dogs;
- dairy desserts with fillers;
- sweetened cereals and bars.
The main hallmark of such products is the presence of ingredients you won’t find in a regular kitchen: high-fructose corn syrup, hydrogenated oils, protein isolates, emulsifiers, and artificial sweeteners. In short, we’re talking about additives. These components, according to the study authors, may be the key factor.
That said, the NOVA classification is not without criticism. It groups together products with vastly different nutritional values: a protein bar with vitamins and a can of Coca-Cola formally end up in the same category. This is one reason why researchers still find it difficult to determine exactly which component of ultra-processed food affects the brain.
Most products on supermarket shelves fall into the ultra-processed category
The link between ultra-processed food and the brain is not yet proven
This study has important limitations, which the authors acknowledge openly. First, it is a cross-sectional study — it captures a snapshot at a single point in time rather than tracking changes over years. It cannot determine what came first: the decline in attention or the increase in ultra-processed food consumption.
There is also a reverse hypothesis: people with already reduced attention and elevated dementia risk may more frequently choose convenient processed products. Additionally, food choices are influenced by where people live and their access to stores with quality products.
Second, the sample is not entirely representative: most participants were white women, many of whom had a family history of dementia. This may limit the applicability of the findings to other population groups.
Finally, ultra-processed food is linked to obesity, diabetes, and high blood pressure — and all of these conditions themselves impair brain function. Therefore, it remains unclear whether industrial food processing affects cognitive functions directly or through a chain of metabolic disruptions.
Nevertheless, the fact that the effect persists even when the quality of the rest of the diet is accounted for makes the results particularly interesting for further investigation.
What ultra-processed food means for concentration
This study is not a reason to panic, but it is a good reason to think. It does not prove that chips cause dementia. But it does show a consistent link between the share of industrially processed food in the diet and deterioration of a specific cognitive function — the ability to focus attention.
The most practical takeaway: simply adding healthy foods to your diet may not be enough if the habit of ultra-processed snacking persists. The study authors emphasize that the degree of food processing is a separate risk factor that is not neutralized merely by increasing the amount of vegetables and fruits on your plate.
For definitive conclusions, long-term studies are needed that follow participants over many years and help determine whether the observed association is causal. For now, this is yet another argument that the ingredient label and the way a product is manufactured deserve just as much attention as its calorie count.
