Crisps. Sugary cereal. Frozen ready meals. Fizzy drinks. If that sounds like a normal week, you're in good company: in countries like the US, Canada and the UK, ultra-processed foods make up more than half of the calories people eat.
What they did
Researchers at McMaster University in Canada looked at brain scans of adults aged 35 to 69, roughly 9,000 people (reports say more than 8,700). Then they compared each scan with how much ultra-processed food that person ate. The study came out in JAMA Network Open on 15 October 2026.
What they found
The biggest ultra-processed eaters were about 40% more likely to have small areas of damage in the brain, sometimes called “silent” strokes. Among women, the top group was twice as likely as the bottom group.
“Silent” means most people feel nothing. But doctors see these marks as early warning signs for stroke and memory problems later in life.
What it doesn't prove
It's a link, not proof that the food did it. The researchers say so themselves, and they need more work to show it's direct. An outside expert, Suzanne Judd, adds that the study doesn't show cutting these foods would protect your brain. Too much sugar and salt can lead to weight gain and diabetes, which can harm the brain on their own. Some volunteers are going back for new scans, with results due in early 2028.
And the price tag
Co-author Russell de Souza made a fair point: with food prices up, cooking from scratch isn't easy for every family. So nobody should feel guilty about a frozen pizza on a busy Tuesday.
What's on your plate?
One bag of crisps won't hurt anyone's brain. This is about habits over years. Swap in a few more real-food meals when you can. Your brain will thank you. Your crisps will survive without you.