Friday, October 22, 2010

What if Bad Fat Is Actually Good for You?

For decades, Americans have been told that saturated fat clogs arteries and causes heart disease. But there's just one problem: No one's ever proved it.

... The first scientific indictment of saturated fat came in 1953. That's the year a physiologist named Ancel Keys, Ph.D., published a highly influential paper titled "Atherosclerosis, a Problem in Newer Public Health." Keys wrote that while the total death rate in the United States was declining, the number of deaths due to heart disease was steadily climbing. And to explain why, he presented a comparison of fat intake and heart disease mortality in six countries: the United States, Canada, Australia, England, Italy, and Japan.

The Americans ate the most fat and had the greatest number of deaths from heart disease; the Japanese ate the least fat and had the fewest deaths from heart disease. The other countries fell neatly in between. The higher the fat intake, according to national diet surveys, the higher the rate of heart disease. And vice versa. Keys called this correlation a "remarkable relationship" and began to publicly hypothesize that consumption of fat- causes heart disease. This became known as the diet-heart hypothesis.

At the time, plenty of scientists were skeptical of Keys's assertions. One such critic was Jacob Yerushalmy, Ph.D., founder of the biostatistics graduate program at the University of California at Berkeley. In a 1957 paper, Yerushalmy pointed out that while data from the six countries Keys examined seemed to support the diet-heart hypothesis, statistics were actually available for 22 countries. And when all 22 were analyzed, the apparent link between fat consumption and heart disease disappeared. For example, the death rate from heart disease in Finland was 24 times that of Mexico, even though fat-consumption rates in the two nations were similar. Read more

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