Learning from the “Fat Hypothesis” and the Intersection of Science and Politics

Image credit: The Guardian

Image credit: The Guardian

by James A. Bacon

Ian Leslie has written a long piece for The Guardian, a left-wing English newspaper that to the best of my knowledge is not funded by the Koch Brothers. He chronicles how the medical hypothesis blaming fat and cholesterol for heart disease became ensconced as scientific orthodoxy in the United States and Great Britain in the 1970s. He shows how that orthodoxy was suborned by government, how it was used with the best of intentions to alter the dietary habits of the two nations, and how it created the obesity epidemic that has shortened the lives of millions. Nearly fifty years later, that orthodoxy is being overthrown as  blame for heart disease increasingly shifts to processed sugar.

At a time when some in Washington, D.C., cite a “consensus” regarding climate change and call for the federal prosecution of climate change “deniers,” the article is worth quoting at some length, for it shows how badly science in the hands of politicians can go off the rails. Leslie does not himself note a parallel between the debates over fat and climate change, but such a comparison is inevitable. Perhaps the article will instill some humility among those tempted to revamp large sectors of the economy based on the latest scientific fashion. At the very least, it should discourage people from snuffing out dissenting scientific voices with threats of criminal prosecution.

In 1980, after long consultation with some of America’s most senior nutrition scientists, the US government issued its first Dietary Guidelines. The guidelines shaped the diets of hundreds of millions of people. Doctors base their advice on them, food companies develop products to comply with them. Their influence extends beyond the US. In 1983, the UK government issued advice that closely followed the American example.

If, as seems increasingly likely, the nutritional advice on which we have relied for 40 years was profoundly flawed, this is not a mistake that can be laid at the door of corporate ogres. Nor can it be passed off as innocuous scientific error. … Instead that this is something the scientists did to themselves – and, consequently, to us.

Ancel Keys was the prime force behind the “fat” hypothesis explaining the increasing rate of heart disease. He posited that excess saturated fats in the diet from red meat, cheese, butter, and eggs raises cholesterol, which congeals on the inside of coronary arteries. The build-up of cholesterol causes the arteries harden, narrow and ultimately staunch the flow of blood until the heart seizes up.

Throughout the 1960s, Keys accumulated institutional power. He secured places for himself and his allies on the boards of the most influential bodies in American healthcare, including the American Heart Association and the National Institutes of Health. From these strongholds, they directed funds to like-minded researchers, and issued authoritative advice to the nation. “People should know the facts,” Keys told Time magazine. “Then if they want to eat themselves to death, let them.”

Keys’ so-called Seven Countries study, published in in 1970,  gathered data on the diets, lifestyles and health of 12,770 middle-aged men, in Italy, Greece, Yugoslavia, Finland, Netherlands, Japan and the United States.

The Seven Countries study [became] canonical, and the fat hypothesis was enshrined in official advice. The congressional committee responsible for the original Dietary Guidelines was chaired by Senator George McGovern. It took most of its evidence from America’s nutritional elite: men from a handful of prestigious universities, most of whom knew or worked with each other, all of whom agreed that fat was the problem – an assumption that McGovern and his fellow senators never seriously questioned.

From Congress flowed a series of measures that pushed the food processing industry to reduce the fat content of food by substituting salt and sugar. Obesity rates soared. The politicians’ mistake was a failure to recognize that scientists are people, too, and they are not exempt from the flaws of lesser mortals.

… A scientist is part of what the Polish philosopher of science Ludwik Fleck called a “thought collective”: a group of people exchanging ideas in a mutually comprehensible idiom. The group, suggested Fleck, inevitably develops a mind of its own, as the individuals in it converge on a way of communicating, thinking and feeling. …

Scientific inquiry [is] prone to the eternal rules of human social life: deference to the charismatic, herding towards majority opinion, punishment for deviance, and intense discomfort with admitting to error. Of course, such tendencies are precisely what the scientific method was invented to correct for, and over the long run, it does a good job of it. In the long run, however, we’re all dead, quite possibly sooner than we would be if we hadn’t been following a diet based on poor advice.

In the past decade, a new generation of scientists and journalists have begun to question the fat hypothesis. The Internet has helped break the control of senior scientists over scientific orthodoxy.

In September last year [Nina Teicholz] wrote an article for the BMJ (formerly the British Medical Journal), which makes the case for the inadequacy of the scientific advice that underpins the Dietary Guidelines. The response of the nutrition establishment was ferocious: 173 scientists – some of whom were on the advisory panel, and many of whose work had been critiqued in Teicholz’s book – signed a letter to the BMJ, demanding it retract the piece.

Publishing a rejoinder to an article is one thing; requesting its erasure is another, conventionally reserved for cases involving fraudulent data. As a consultant oncologist for the NHS, Santhanam Sundar, pointed out in a response to the letter on the BMJ website: “Scientific discussion helps to advance science. Calls for retraction, particularly from those in eminent positions, are unscientific and frankly disturbing.”

By opening the gates of publishing to all, the internet has flattened hierarchies everywhere they exist. We no longer live in a world in which elites of accredited experts are able to dominate conversations about complex or contested matters. Politicians cannot rely on the aura of office to persuade, newspapers struggle to assert the superior integrity of their stories. It is not clear that this change is, overall, a boon for the public realm. But in areas where experts have a track record of getting it wrong, it is hard to see how it could be worse. If ever there was a case that an information democracy, even a very messy one, is preferable to an information oligarchy, then the history of nutrition advice is it.