High-fat foods can reduce intelligence in just 9 days, research finds.
Cognitive performance reduced by 20% in just over a week after eating a high-fat diet.
The study on rats fed them a diet equivalent to human junk food.
After nine days, not only was their cognitive performance affected, but their physical performance was reduced by 50%.
The short-term effects of a high-fat diet are startling, the researchers say.
A previous study has found a high-fat diet can reduce cognitive performance in humans as well.
Dr Andrew Murray, the study’s first author, said:
“We found that rats, when switched to a high-fat diet from their standard low-fat feed, showed a surprisingly quick reduction in their physical performance.
After just nine days, they were only able to run 50 per cent as far on a treadmill as those that remained on the low-fat feed.”
The conclusions come from a study of rats who were initially fed on a standard low-fat diet.
Half were then switched to a high-fat diet.
Dr Andrew Murray explained how these diets translate to what humans eat:
“With the standard feed, 7.5 per cent of the calories come from fat.
That’s a pretty low-fat diet, much like humans eating nothing but muesli.
The high-fat diet, in which 55 per cent of the calories came from fat, sounds high but it’s actually not extraordinarily high by human standards.
A junk food diet would come close to that.”
The results showed that after nine days the rats fed on a high-fat diet made 20% more errors when learning to navigate a maze.
They were also running 50% less far.
The researchers also found that the rats’ hearts were enlarged with the increased effort of pumping blood around their bodies.
Professor Kieran Clarke, study co-author, said:
“These are startling results.
It shows that high-fat feeding even over short periods of time can markedly affect gene expression, metabolism and physical performance.”
Professor Jeremy Pearson said:
“In little more than a week, a change in diet appears to have made the rats’ hearts much less efficient.
We look forward to the results of the equivalent studies in human volunteers, which should tell us more about the short-term effects of high-fat foods on our hearts.
We already know that to protect our heart health in the long-term, we should cut down on foods high in saturated fat.”
About the author
Psychologist, Jeremy Dean, PhD is the founder and author of PsyBlog. He holds a doctorate in psychology from University College London and two other advanced degrees in psychology.
He has been writing about scientific research on PsyBlog since 2004. He is also the author of the book “Making Habits, Breaking Habits” (Da Capo, 2013) and several ebooks:
- Accept Yourself: How to feel a profound sense of warmth and self-compassion
- The Anxiety Plan: 42 Strategies For Worry, Phobias, OCD and Panic
- Spark: 17 Steps That Will Boost Your Motivation For Anything
- Activate: How To Find Joy Again By Changing What You Do
The study was published in The FASEB Journal (Murray et al., 2009).