Blog | Tuesday, January 5, 2016

How experts agree while looking like they don't

I have been gratified by, and fascinated with, the extensive media coverage since the recent, groundbreaking Oldways Common Ground conference on healthy eating. That the conference was legitimately groundbreaking is a case I have myself made. What other journalists have chosen to highlight varies widely and is the source of my fascination. Those who chose as their focus the product of the conference sounded a lot like me, noting the remarkable consensus achieved. Those who focused on the process tended to dwell on discord rather than consensus.

That these journalistic perspectives are complementary rather than competitive, rather like the diverse views of the participating nutrition scientists themselves, is the grist for today's milling.

To make the case without premature activation of any native passion on the topic, and thus the selective deafness that can follow, I will avoid the topic of nutrition altogether. Let's consider instead the matter of bridges, and how building them might look surprisingly like burning them.

Let us imagine a conference on advances in the building of suspension bridges. To add a patina of verisimilitude to this thought experiment, I Googled “conferences for industrial engineers” just now, and sure enough, they gather in the very way we are about to pretend. I added “suspension bridges,” and yes, that specific topic is addressed at some of those conferences. We are good to proceed.

We may reasonably assume that the audience at such a conference is rather exclusive to those with deep interest and expertise in the particulars of bridges, industrial engineers, structural engineers, architects, and so on, and that the roster of speakers represents even more rarefied expertise in those same areas. Who else would go?

Is it likely the conference would open, assert a common understanding of the one, best way to build a suspension bridge, and then adjourn? Obviously not; there would be no point whatever in going to the trouble of convening a conference in the first place for such an anticlimax.

One may confidently presume that the experts at any such conference would opine at some length, offering insights about different methods, different materials, and preferred refinements. That would be the very point of holding a conference, devoted to advancements in the understanding of bridges.

If any of those experts were asked, perhaps right after his or her keynote, about the “best” way to build a suspension bridge, they could be forgiven for proffering their own. After all, that's part and parcel of being an expert; you develop deeper knowledge of, and along with it deeper personal attachment to, a given topic than a non-expert. That's what expertise is.

As an expert, it would make little sense to devote your years and energy to any aspect of your field that you found less promising, interesting, or important than another. You would, reliably, allocate those precious resources exactly where you saw the greatest opportunity. When asked what matters most, you would tend to talk about what you do, because you would tend to do what you decided matters. The reasoning here is all the more robust for going around in so vivid a loop.

This, of course, would be true for all speakers in roughly comparable measure. For any given expert, years focused on some aspect of a larger field that began with passion and preference, and resulted in more of the same, would produce a predictable response to: What is best? The answer from all really should be some variation on the theme of: my way! Why on earth, when asked about what matters most, would you indicate anything other than your own, career-long devotion? If you actually thought some other aspect of your field mattered more, you would, presumably, have long since rerouted your career in that direction.

So, simply asking scientists to express their devotion to the work they do can create the appearance of discord; each expert indicates some particular preference at odds with all the others. If we ask Expert 1 if her method is the best, she will undoubtedly say yes, and tell us why. If we ask Expert 2 if Expert 1's method is the best, he will doubtless say no, and tell us why his is better. Few responses hint at commonality with the penuriousness of “yes” and “no.”

But ask different questions, and an entirely alternative reality unfolds. Would these experts agree that they both use materials and methods more alike than different? Why, yes. Would they agree that the other is, in fact, a genuine expert? Well, certainly. Do they respect one another? Indeed. Would they be willing to drive their family across a bridge constructed by their counterpart? Assuredly so, with confidence and calm. Would they be willing to drive across a bridge constructed by a random citizen with no relevant training or expertise in their field? Heaven forbid!

It's just the same in nutrition. I know in part because I have done something rather analogous to driving across suspension bridges with many of the world's bridge experts; I have shared meals with many of the world's nutrition experts across an expanse of conferences, decades, and continents. When it comes time to opine to the public, we can sound like we differ radically about everything, because we each emphasize that thing we do. But when it comes time to sit down and eat, our plates, inevitably, look remarkably similar to each other, and nothing like the “typical American” meal.

The notion that no 2 nutrition experts agree about anything is wrong. The contention that any individual nutrition expert's opinion changes every 20 minutes is also wrong. In fact, these are not merely false propositions, but profoundly, abjectly so. The fundamentals of understanding in nutrition are remarkably time-honored, spanning, believe it or not, millennia, to say nothing of recent decades. There is not just a general agreement about those fundamentals; there is a massive, global consensus among stunningly diverse experts. I have proof.

We may concede, however, that the stability and unanimity of expert opinion sure is hard to see. Partly, that's because of experts themselves emphasizing what makes each of us unique, rather than what makes us alike. Mostly, however, it is because there is profit to be had, enormous profit, in obscuring the truth about diet, and the consensus about it.

The way experts express expertise may make it seem as if the only thing we ever do with bridges is burn them. In reality, we may have been building them all along, with methods and materials far more alike than different.

David L. Katz, MD, FACP, MPH, FACPM, is an internationally renowned authority on nutrition, weight management, and the prevention of chronic disease, and an internationally recognized leader in integrative medicine and patient-centered care. He is a board certified specialist in both Internal Medicine, and Preventive Medicine/Public Health, and Associate Professor (adjunct) in Public Health Practice at the Yale University School of Medicine. He is the Director and founder (1998) of Yale University's Prevention Research Center; Director and founder of the Integrative Medicine Center at Griffin Hospital (2000) in Derby, Conn.; founder and president of the non-profit Turn the Tide Foundation; and formerly the Director of Medical Studies in Public Health at the Yale School of Medicine for eight years. This post originally appeared on his blog at The Huffington Post.