Diet and the art of denying the obvious

Scarcely a week goes by these days without hearing yet again from some perch of lofty intellectual reflection that we know nothing about the basic feeding of Homo sapiens. We are told our research is flawed, our assessments useless and thus our knowledge permanently something near to nil.

If true, this would be deeply disturbing. Diet has been firmly planted on the short list of leading root causes of premature death and chronic disease in the United States for the past quarter century. It has evolved to become the No. 1 cause, and around an ever-growing swathe of the world. Imagine actually knowing nothing about the single factor that siphons away the most years from lives, the most life from years in the modern world. If true, it would seem to signal an urgent, desperate need to figure something out fast so that corrective action could be taken.

But this narrative of perennial befuddlement — is entirely untrue. We actually know more than enough about diet and health, the full range of crucial, fundamental truths to prevent up to 80 percent of chronic disease and premature death in the industrialized countries around the world. We know enough to reduce personal risk by that same sum. So how is it we can even manage to seem so utterly and perennially clueless on the topic?

Easy. The whole explanation spills out of the simplest of thought experiments. Let’s imagine we are studying exercise the way we study diet.

Imagine, for instance, researchers pursuing the implications of fashion for fitness.

One group would report the benefits of hiking in earth tones. Another, however, might publish on the benefits of hiking in pastels. Yet another would muddy the waters by introducing another variable and note the advantages of indoor aerobics wearing primary colors.

Then, our problems would begin. Those favoring any given color would design trials to favor that color (designing studies to favor a desired answer is far easier than you might think). They might, for instance, recruit a group inclined to wear earth tones, then randomly assign them to hike in those favored hues, or in pastels. Those in pastels, distraught and distracted by their sartorial misfortunes, would be less happy and energetic. This group would tell us the benefits of hiking are obviated by the wearing of pastels.

The other group, of course, would do something diabolically clever, and diametrically opposed, and wind up publishing a study that explained the clear superiority of pastels.

The media would treat both studies as absolute truth for their respective span of 20 seconds in the sun, largely ignoring their extreme mutual incompatibility. An anointed uberintellectual would eventually publish a commentary in a prestigious journal, far more widely read than either study, and spawning a third set of headlines, telling us that such conflicts of hue obviate all knowledge of any alleged health benefits of exercise.

And we, in our gullible, complicit, colluding multitudes, would head back to the couch, remote in hand, with a smug “I knew it all along” look on our faces.

And this, of course, is just the first sedentary toe in the vast waters of our burgeoning exercise confusion.

We could study every version of every kind of footwear, underwear, hats and gloves. We could study temperature, time of day, dew point. We could study latitude, longitude, spirituality and choice of toothpaste.

The contention that we are clueless about diet and health, that all measures are bereft, all knowledge suspect, all research questions however seemingly inane admissible, is the rubbish it seems. It is a pop culture myth. The notion that we can only know with data from a randomized controlled trial is as well; just ask yourself if you really need to find a meta-analysis to know whether to use water or gasoline to put out your next campfire.

Mountains of evidence, the meanest application of sense, common experience and the consensus perspective and personal practices of the world’s leading experts all point to the same fundamental truths about diet and health.

A long list of entities profit by denying this. But there’s no denying the obvious: That list probably does not include you.