The Mistaken Consensus in Dietary Restrictions
article: http://www.nytimes.com/2007/10/09/science/09tier.html
It’s become popular wisdom nowadays that a low-fat diet is healthy and can prevent heart disease. But what scientific evidence actually exists to prove this claim? John Tierney in this article claims that the low-fat diet fad is the result of an informational and reputational cascade. The cascade starts when people start believing an idea just because it is the majority consensus, and they assume it cannot be wrong because most other people believe it.
Tierney says that these kinds of cascades are especially common in the medical field because many doctors are unable to keep up with the volume of research, so they turn to experts, or someone that sounds confident, for an answer. In the case of fatty foods, a prominent diet researched named Ancel Keys, became convinced in the 1950s that Americans were suffering from heart disease because of an increase in fatty foods in their diets. His theory was flawed and not backed by scientific evidence, but people believed him because he was an “expert” in dietary research. Further, people who openly opposed the theory were ostracized for going against popular wisdom. The American Cancer society recommended a low-fat diet for anyone over the age of 2 in order to prevent cancer. But when these theories were tested, the evidence turned up negative.
This dietary misconception is a perfect example of the information cascade patterns we studied in lecture. Similar to the marble-drawing situation, people would continue to believe the idea of a low-fat diet because the majority of other people also did. Even when there was evidence against the popular wisdom, people did not want to go against the majority opinion in fear of being criticized, a phenomenon Thiery describes as reputational wisdom.