A Western-Style Diet Could Affect the Brain in as Little as a Week

That classic American breakfast may lock us into a viciousjunk food cycle. Brent Hofacker/Shutterstock

If you happen to be waffling on what you'd like for breakfast, consider this:

What you eat may catch up with you — particularly, your brain — a lot faster than you think.

In fact, a new study suggests it takes just a week for a diet high in sugar and fat — the classic Western-style meal — to have a notable impact on the hippocampus region of the brain. Not only that, but those foods may lock people into a cycle of junk food binging and overeating.

The study, published this week in Royal Society Open Science, looked at 110 lean and healthy students, all in their early 20s. After feeding them a traditional "Western" diet — one heavy on sugar, fats and processed foods — for seven days, researchers noted a consistently downward spiral in memory tests. Not only that, but participants also seemed to find junk food more tantalizing after they had finished a Western meal.

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

It gets even more alarming.

Waffles, pancakes, eggs, toast, cheese — it's not so much a breakfast of champions, but rather the breakfast of Homer Simpsons. It may flat-out be making toast of our brains.

The breakdown, according to the research paper, takes place in the hippocampus — a part of the brain strongly linked to memory and appetite control. Fats and sugars play all kinds of tricks on it.

As a 2017 study that looked at the hippocampus in animals suggests it may have a subtle, but powerful effect on how we look at food. When a body is full, for example, the hippocampus kindly refrains from reminding us how good cake tastes. We're more likely to pass on a slice after a satisfying meal.

But certain meals could compromise the hippocampus. In the recent study, participants who ate a Western-style still felt like they had room for Coco Pops, Frosties and Froot Loops.

"The more desirable people find the palatable food when full, following the Western-style diet, the more impaired they were on the test of hippocampal function," Stevenson tells the Guardian.

Illustration of a brain with a donut in the middle.
Normally, the hippocampus acts as a kind of gatekeeper for appetite. But a Western diet may compromise its judgment. canbedone/Shutterstock

In effect, people on Western diets — think waffles and toast and jam — are locked into a cycle of eating fats and sugars and processed foods and then craving more fats and sugars and processed foods.

And that may not only be contributing to an obesity epidemic among Americans, but also feeding a host of diseases from diabetes to dementia.

Not to mention diminished brain performance.

"The new thinking here is the realisation that a western-style diet may be generating initial and fairly subtle cognitive impairments, that undermine the control of appetite which gradually opens the way for all of these other effects down the track," Stevenson adds.