It’s not what most people would consider food, but alcohol has some extreme effects on the brain when consumed in excess.
The evidence that artificial sweeteners cause cognitive decline is a bit all over the place; it’s clear that more research on the subject is needed.
Most people are well aware that fried foods aren’t good for them.
Refined carbohydrates, such as those found in pasta, white bread, and pastries, have a high glycemic index. Eating them causes your blood sugar to spike.