waffles

A diet high in fat and sugar can impair mental abilities, a new study has found.
Mmmmm doughnuts.

A "Western-style" diet makes you Homer Simpson-level stupid, according to a new study published in the Royal Society.

Even if you're slim and healthy, eating a high-fat, high-sugar diet for just a week was found to impact brain function and make it harder for people to control their appetites, the researchers from Australia, the US and England found.

"After a week on a Western-style diet, palatable food such as snacks and chocolate becomes more desirable when you are full," Richard Stevenson, a professor of psychology at Macquarie University in Sydney and one of the study's authors tells the Guardian. "This will make it harder to resist, leading you to eat more, which in turn generates more damage to the hippocampus."

He calls the response "a vicious cycle of overeating."

Past research had shown that a "Western-style" diet — generally defined as a diet high in fat, sugar and processed foods — impaired brain function in animals. Researchers suspected the same would happen in humans.

For this study, researchers recruited 110 lean and healthy adults ages 20 to 23, all of whom were self-described healthy eaters. Half of the group ate their normal diets for a week. The other half ate a "Western-style" diet heavy on waffles and fast food.

Those on the "Western-style" diet performed worse on memory tests than the healthy-eating group and also had "measurable weakening of appetitive control," which leads to overeating, the researchers said.

"Demonstrating that processed foods can lead to subtle cognitive impairments that affect appetite and serve to promote overeating in otherwise healthy young people should be a worrying finding for everyone," Stevenson told the Guardian.

Earlier this week, researchers at UC Davis Health found that a "Western diet" may also lead to skin diseases. The study, published in the Journal of Investigative Dermatology, suggested that what we eat "may lead to skin inflammation and the development of psoriasis," rather than obesity itself.