Cheating on your diet could lead to weight gain, but if you follow the Mediterranean diet and switch to unhealthy foods you may also make your brain age faster. A team from Rush University Medical Center found that adding in foods from the Western diet, such as pizza, sweets and processed meats, reverse cognitive benefits from the Mediterranean diet. The study examined more than 5,000 individuals over the age of 65 from 1993 to 2021 and over the course of three years participants were asked to complete cognitive tests and report on how often the ate certain foods. Researcher recently compiled the data and found those who stuck to the Mediterranean diet had brains that were nearly six years younger than their peers on the Western diet. The Mediterranean diet is inspired by the eating habits of Spain, Italy and Greece, and focuses on consuming more fruit and fish and limiting sugar, dairy and processed foods.

Our Western diet is famously bad for the circulatory system, but for a long time, people thought the damage stopped there. Then around 10 years ago, Terry Davidson, a behavioral neuroscientist, wondered whether our modern eating habits might also affect our brains. To test it out, he fed lab rats a diet high in saturated fats and sugars. He found that the animals had problems learning various memory tasks for which they'd get rewards. Their difficulties were probably linked to changes in the way blood reaches a portion of the brain called the hippocampus.