Diet and Fat: A Severe Case of Mistaken Consensus
October 25, 2007
In 1988, surgeon general C. Everett Koop made a statement that changed the course of American’s diets for many years to come. He said that high-fat foods were causing coronary heart disease and other deadly problems in Americans, and these high-fat foods were just as dangerous to public health as cigarettes.
Koop said, in the report detailing his fat findings, “The depth of the science base underlying its findings is even more impressive than that for tobacco and health in 1964.”
As it turned out, Koop’s statement was wrong.
What led a respected surgeon general to make such a mistake? According to this New York Times article, it was a case of an “informational cascade.”
A cascade of information can easily lead to the wrong conclusion.
It works like this: Someone has a bit of wrong information, but they are confident about it so they spout it out. A second person who is unsure decides that the first person must be right, and chooses to go along with their theory. A third person who may have had a right answer, then changes his mind because he believes the two others must know more than him.
And on it goes as each person assumes the others can’t be wrong.
Who was the first person to start the cascade of misinformation about fatty foods? It was Ancel Keys, a diet researcher for whom military K-rations are named.
He believed that dietary fat was causing heart disease in Americans back in the 1950s, and he soon got others to jump on the bandwagon.
Even the American Heart Association, which concluded in 1957 that “the evidence that dietary fat correlates with heart disease does not stand up to critical examination,” changed its position in 1960.
Why? Because Keys was on the committee issuing a new report that a low-fat diet was advised for people at risk of heart disease.
Since then, the “fat is bad” theory continued to be accepted as nutritional wisdom, even though clinical trials found no connection.