Diet and Fat: A Severe Case of Mistaken Consensus (NYTimes.com)

This article makes the point that the consensus on the health benefits of fat reduction in the diet are not scientifically born out. Instead it’s the result of the moral equivalent of the herding instinct for scientists.

Could this be true? A basic dietary assumption of the past 40 years was a whoops? And if scientists were wrong about something this fundamental, what else could they be wrong about.

Maybe Woody Allen’s predictions in the movie “Sleeper” really will come true (Ie., in the future, steak and cigarettes are determined to be healthy)

From the NYTimes.com:

In 1988, the surgeon general, C. Everett Koop, proclaimed ice cream to a be public-health menace right up there with cigarettes. Alluding to his office’s famous 1964 report on the perils of smoking, Dr. Koop announced that the American diet was a problem of “comparable” magnitude, chiefly because of the high-fat foods that were causing coronary heart disease and other deadly ailments.

He introduced his report with these words: “The depth of the science base underlying its findings is even more impressive than that for tobacco and health in 1964.”

That was a ludicrous statement, as Gary Taubes demonstrates in his new book meticulously debunking diet myths, “Good Calories, Bad Calories” (Knopf, 2007). The notion that fatty foods shorten your life began as a hypothesis based on dubious assumptions and data; when scientists tried to confirm it they failed repeatedly. The evidence against Häagen-Dazs was nothing like the evidence against Marlboros.

It may seem bizarre that a surgeon general could go so wrong. After all, wasn’t it his job to express the scientific consensus? But that was the problem. Dr. Koop was expressing the consensus. He, like 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.

Because of this effect, groups are surprisingly prone to reach mistaken conclusions even when most of the people started out knowing better, according to the economists Sushil Bikhchandani, David Hirshleifer and Ivo Welch. If, say, 60 percent of a group’s members have been given information pointing them to the right answer (while the rest have information pointing to the wrong answer), there is still about a one-in-three chance that the group will cascade to a mistaken consensus….


And on the same theme, the NYTimes article “Diabetes Study Partially Halted After Deaths” also contradicts a long held medical assumption:

..a major federal study of more than 10,000 middle-aged and older people with Type 2 diabetes has found that lowering blood sugar actually increased their risk of death, researchers reported Wednesday (1/6/08)

Author: Ben Slade

I'm a software technologist with a political bent. My views tend toward the contrarian and slightly curmudgeonly end of the spectrum.

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