The fallibility of science

I’m old enough to remember when people were advised by severe-faced nutritionists about the dangers of eggs, all the while being totally unaware of the possible downsides of gorging on high-sugar, fat-free SnackWells cookies. This was the 1980s and early 1990s, when low fat and cholesterol were all the rage. Now The Washington Post is reporting that The U.S. government is poised to withdraw longstanding warnings about cholesterol. It’s a deeply reported story, so read the whole thing. This comes in the wake of research which debunks very low sodium diets, as well Time coming out with articles such as Where Dietary-Fat Guidelines Went Wrong. There are still debates about the details, with some people moving toward a very high fat diet, somewhat as a reaction to past anti-fat excesses I believe.

A lot of this collapse of the old orthodoxy can probably be traced back to Gary Taubes, at least in the public consciousness (see his The New York Times Magazine piece from 2002). Taubes and company now put sugar into the same category that fat and cholesterol were, though for somewhat different reasons (ergo, the focus on types of calories ingested). But health is not the only concern. Hundreds of millions of people have made their food less savory over a generation because of these false recommendations.

In The Washington Post the article concludes:

“These reversals in the field do make us wonder and scratch our heads,” said David Allison, a public health professor at the University of Alabama at Birmingham. “But in science, change is normal and expected.”

When our view of the cosmos shifted from Ptolemy to Copernicus to Newton and Einstein, Allison said, “the reaction was not to say, ‘Oh my gosh, something is wrong with physics!’ We say, ‘Oh my gosh, isn’t this cool?’ ”

Allison said the problem in nutrition stems from the arrogance that sometimes accompanies dietary advice. A little humility could go a long way.

“Where nutrition has some trouble,” he said, “is all the confidence and vitriol and moralism that goes along with our recommendations.”

A lot about nutrition is tied up to morality, and our ancient psychological fixations on the “purity” of food. That’s why no matter what people say about veganism, or paleo, or high/low fat/sugar/carb, in terms of its functional health consequences, it’s really about the values that you are projecting in terms of the psychology. And that’s why we tend to get into dietary moral panics so often. Because nutrition has a lot of variables producing an output (weight or overall health) it’s difficult to assess which ones are effecting change. If gunnery specialists were using non-Newtonian physics to land hits on the enemy we’d know pretty quickly that non-Newtonian physics (or at least pre-Newtonian mechanical intuition) just didn’t work. Though heart disease rates have gone down, Americans have become more obese. The signals are mixed. Meanwhile many of us are turning our lives upside down, eliminating or adding food elements on the latest research, which is often overturned or found to be statistically not robust. No wonder many people have started to tune out any health advice from the “authorities.”

Of course there is science, and there is science. Germ theory and epidemiology in relation to viral infections and vaccinations are a robust era of science. Planetary mechanics as well. In contrast many areas of nutritional, medical, and social science remain highly uncertain and low in confidence as to the nature of the results. You wouldn’t get that from the “experts” though. Science is science when they hold forth from on high. Except it’s not.

Addendum: I forgot to mention this, but one clear issue in regards to nutrition is sensitivity to particular individuals and populations. One of the ridiculousness of modern nutrition is how lowest-common-denominator and one-size-fits-all it seems to be. Yes, I’m generalizing here, but I know people with heritable familial cholesterol who were recommended to exercise and avoid eating a wide array by nutritionists even when this condition was already known to run in the family, and, the individuals in question were relatively fit. It was obvious that lifestyle and diet were marginal variables here, but the nutritionists simply could not imagine going off script.

If you have a family history of hypertension and stroke, by all means avoid salt. But it seems that for most of the population the downside risk to flavor is small to non-existent. Apparently the same might apply to cholesterol. And sorry, I think the same also applies to sugar! There are people who are more resistant to metabolic disease. If you enjoined the whole populations to avoid food that 10-25% might gain nutritional benefit, pretty soon that means everyone will eat literally nothing, because we all have different Achilles’ heels.