How Science By Cascade Caused Bad Diet Advice

The New York Times has a great article about how the American Diet was lead astray by the assumption that eating fat makes us fat. The Times had a head start on "The Big Fat Lie" by running a Times Magazine cover story on the subject a few years ago. Now the author -- science writer Gary Taubes -- has a new book out "Good Calories, Bad Calories" describing how bad science and bad information may have played a role in our national obesity. As Taubes wrote in July of 2002:

"If the members of the American medical establishment were to have a
collective find-yourself-standing-naked-in-Times-Square-type nightmare,
this might be it. They spend 30 years ridiculing Robert Atkins, author
of the phenomenally-best-selling ''Dr. Atkins' Diet Revolution'' and
''Dr. Atkins' New Diet Revolution,'' accusing the Manhattan doctor of
quackery and fraud, only to discover that the unrepentant Atkins was
right all along. Or maybe it's this: they find that their very own
dietary recommendations -- eat less fat and more carbohydrates -- are
the cause of the rampaging epidemic of obesity in America. Or, just
possibly this: they find out both of the above are true."

"Over the past five years, however, there has been a subtle shift in the
scientific consensus. It used to be that even considering the
possibility of the alternative hypothesis, let alone researching it,
was tantamount to quackery by association. Now a small but growing
minority of establishment researchers have come to take seriously what
the low-carb-diet doctors have been saying all along. Walter Willett,
chairman of the department of nutrition at the Harvard School of Public
Health, may be the most visible proponent of testing this heretic
hypothesis. Willett is the de facto spokesman of the longest-running,
most comprehensive diet and health studies ever performed, which have
already cost upward of $100 million and include data on nearly 300,000
individuals. Those data, says Willett, clearly contradict the
low-fat-is-good-health message ''and the idea that all fat is bad for
you; the exclusive focus on adverse effects of fat may have contributed
to the obesity epidemic.''

Yet, if fat isn't as bad for us as we've been lead to believe, why has the medical community been in harmonious agreement on the subject -- incorrectly -- all these years? Today's Times article explains that a "cascade" of theories piled upon each other despite clinical evidence to the contrary. How?

"....the architects of the federal “food pyramid” telling Americans what
to eat, went wrong by listening to everyone else. He was caught in what
social scientists call a cascade. We like to think that people
improve their judgment by putting their minds together, and sometimes
they do. The studio audience at “Who Wants to Be a Millionaire” usually
votes for the right answer. But suppose, instead of the audience
members voting silently in unison, they voted out loud one after
another. And suppose the first person gets it wrong. If the second person isn’t sure of the answer, he’s liable to go along
with the first person’s guess. By then, even if the third person
suspects another answer is right, she’s more liable to go along just
because she assumes the first two together know more than she does.
Thus begins an “informational cascade” as one person after another
assumes that the rest can’t all be wrong."

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