If you feel lethargic or that your memory is slipping, diet may be a factor.   A new research study says that in less than 10 days of eating a high-fat diet, rats had decreased ability to exercise and experienced significant short-term memory loss. The researchers say the results show an important link between what we eat, how we think, and how our bodies perform. 

Andrew Murray, co-author of the study and currently at the University of Cambridge, 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). They discovered that the muscles of the 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. Researchers then investigated the cellular causes of these problems, particularly in the mitochondria of muscle cells.

They 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. 

"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 Murray. "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."

"It's nothing short of a high-fat hangover," said Gerald Weissmann, M.D., Editor-in-Chief of The FASEB Journal which published the results. "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."

Article: 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. doi:10.1096/fj.09-139691