But when the theories were tested in clinical trials, the evidence kept turning up negative. As Mr. Taubes notes, the most rigorous meta-analysis of the clinical trials of low-fat diets, published in 2001 by the Cochrane Collaboration, concluded that they had no significant effect on mortality.
Mr. Taubes argues that the low-fat recommendations, besides being unjustified, may well have harmed Americans by encouraging them to switch to carbohydrates, which he believes cause obesity and disease. He acknowledges that that hypothesis is unproved, and that the low-carb diet fad could turn out to be another mistaken cascade. The problem, he says, is that the low-carb hypothesis hasn’t been seriously studied because it couldn’t be reconciled with the low-fat dogma.
Mr. Taubes told me he especially admired the iconoclasm of Dr. Edward H. Ahrens Jr., a lipids researcher who spoke out against the McGovern committee’s report. Mr. McGovern subsequently asked him at a hearing to reconcile his skepticism with a survey showing that the low-fat recommendations were endorsed by 92 percent of “the world’s leading doctors.”
“Senator McGovern, I recognize the disadvantage of being in the minority,” Dr. Ahrens replied. Then he pointed out that most of the doctors in the survey were relying on secondhand knowledge because they didn’t work in this field themselves.
“This is a matter,” he continued, “of such enormous social, economic and medical importance that it must be evaluated with our eyes completely open. Thus I would hate to see this issue settled by anything that smacks of a Gallup poll.” Or a cascade.
A very interesting read, with some good points about the "cascade" effect--especially for someone like me in the medical profession where such fads come and go.
Does anyone see any parallels to current events--e.g., the supposed "scientific concensus" on global warming?
Rand Simberg at Transterestrial Musings notes:
Of course, it doesn't mean that all theories have this problem. But it does mean that we are entitled to a little skepticism when we are told that there is a scientific consensus. Particularly when we are bullied into believing it, and treated like heretics in our skepticism, and there are some other potential agendas at play.
In general, it is probably always wise to be skeptical of science when it is promoted by politics--or polls.