Fatty Foods for Thought

Can't remember what you ate for breakfast yesterday? It could be because you polished off that bacon on your plate.

In a controlled study cowritten by Gordon Winocur, Ph.D., a senior scientist at the Rotman Research Institute in Toronto and a psychology and psychiatry professor at the University of Toronto, rats who were fed a diet consisting of 40% fat—similar to what many Americans eat—showed reduced cognitive function. "[The reduced ability] was widespread, and it ran the spectrum of cognitive functions—memory, spatial ability, rule-learning and so on," says Winocur, whose study was published in the journal Neurobiology of Learning and Memory. Rats that ate a diet high in saturated fat suffered more impairment than those who ate mainly unsaturated fat.

Fat can clog arteries and cause a buildup of plaque that reduces blood flow. If blood flow to the brain is affected, brain function may be as well. Fat can also impede the ability of cells to metabolize glucose, a type of sugar found in the blood that the brain uses for energy. Glucose deficiency is known to cause brain impairment.

A high-fat diet may make rats scatterbrained, but what about humans? "That's the big question," says Winocur. Rat and human brains behave similarly, so he believes that we should be concerned, especially when so many people indulge in fatty foods.