How Bad is a High Fat Diet?

High-Fat Diet May Make You Stupid and Lazy

Short-term memory getting worse? Exercise getting harder? Examine your diet. New research published online in The FASEB Journal (http://www.fasebj.org) showed that in less than 10 days of eating a high-fat diet, rats had a decreased ability to exercise and experienced significant short-term memory loss. These results show an important link between what we eat, how we think, and how our bodies perform.

"Western diets are typically high in fat and are associated with long-term complications, such as obesity, diabetes, and heart failure, yet the short-term consequences of such diets have been given relatively little attention," said Andrew Murray, co-author of the study and currently at the University of Cambridge in the United Kingdom. "We hope that the findings of our study will help people to think seriously about reducing the fat content of their daily food intake to the immediate benefit of their general health, well-being, and alertness."

Rodents are thought to be good analogues to humans for studies like this, but research in humans would be needed to confirm that the effects cross over. Also, because rats live much shorter lives, study effects may play out on significantly shorter time scales than in humans.

Murray and colleagues studied rats fed a low-fat diet (7.5 percent of calories as fat) and rats fed a high-fat diet (55 percent of calories as fat). Muscles of rats eating the high-fat diet for four days were less able to use oxygen to make the energy needed to exercise, causing their hearts to worker harder - and increase in size.

After nine days on a high-fat diet, the rats took longer to complete a maze and made more mistakes in the process than their low-fat-diet counterparts.

In the fat-laden rats the researchers found increased levels of a protein called uncoupling protein 3, which made them less efficient at using oxygen needed to make the energy required for running.

"It's nothing short of a high-fat hangover," said Dr. Gerald Weissmann, editor-in-chief of journal. "A long weekend spent eating hotdogs, French fries, and pizza in Orlando might be a great treat for our taste buds, but they might send our muscles and brains out to lunch."
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Andrew J. Murray, Nicholas S. Knight, Lowri E. Cochlin, Sara McAleese, Robert M. J. Deacon, J. Nicholas P. Rawlins, and Kieran Clarke
Deterioration of physical performance and cognitive function in rats with short-term high-fat feeding
FASEB J. first published on August 10, 2009 as doi:10.1096/fj.09-139691 Abstract

The full article is available online but only for FASEB members (which I am not).