Junk Food is Rotting Your Brain and the Research Proves it

In the fitness world, people avoid ultraprocessed foods due to their high calorie content and lack of nutrients. Combine that with the fact that they are not filling, especially when compared to fresh foods, and this makes them a poor choice for anyone concerned about their physical health.

But new research suggests that these junk foods may also impact your cognitive health.

Researchers reviewed 16 studies published up to 2026 to see whether eating lots of ultraprocessed foods is linked to worse memory, thinking, and decision-making in adults. Ultraprocessed foods were defined as your typical junk food: pre-packaged snacks, fast food, sugary drinks, etc.

About 81% of the studies found that higher consumption was linked to worse cognitive performance. These include memory, focus, and executive function (your ability to plan, make decisions, and control impulses).

This was especially apparent in older adults. The strongest and most consistent evidence was in people over 65 years old. Higher intake was repeatedly linked to faster cognitive decline, greater risk of mild cognitive impairment, and higher dementia risk.

In middle-aged adults, two studies found that getting more than 20% of daily calories from ultraprocessed foods led to noticeably faster decline in both overall cognition and executive function.

The possible mechanisms are easy to spot. Ultraprocessed foods lack the vitamins and minerals necessary for proper cognitive function. They may also disrupt the gut microbiome, which has an effect on brain health.

It's important to note that these are observational studies, not direct cause-and-effect. Among the studies, there were also different interpretations of what are considered ultraprocessed foods. It's also hard to control for confounding variables like sleep, physical activity, and education.

Regardless, it's highly unlikely that ultraprocessed foods are beneficial in any way. The evidence linking them to poor physical health is already well established, and the emerging research on cognitive decline only adds to the case against them. While we can't yet say definitively that junk food causes brain damage, the pattern across these studies is hard to ignore.

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This story was originally published May 27, 2026 at 2:06 PM.