An informational cascade

Is the connection between fat and diet an example of a mistaken consensus?

An "informational cascade" as one person after assumes that the rest can't be all wrong.

Because of this effect, groups are surprisingly prone to reach mistaken conclusions even when most of the people started out knowing better....Cascades are especially common in medicine as doctors take their cues from others, leading them to overdiagnose some faddish ailments (called bandwagon diseases) and overprescribe certain treatments (like the tonsillectomies once popular for children). Unable to keep up with the volume of research, doctors look for guidance from an expert — or at least someone who sounds confident.

John Tierney on Diet and Fat: A Severe Case of Mistaken Consensus

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.

UPDATE: Sissy Willis does much deeper analysis of both the Tierney piece and informational cascades in "There are very few who can think, but every man wants to have an opinion."