Older male rats that eat a lot of sugary, processed carbs for a month start to forget things better and show signs of brain inflammation—this might be why aging brains get worse when we eat too many junk foods.

The study found that old rats fed a junk-food diet with lots of sugar and white flour had worse memory and more brain inflammation — just like the claim said. Adding a healthy fat helped, but the junk food still caused the problems.