04/07/2014 04:06 pm ET Updated Jun 07, 2014

iDietology: Why I'm Fed Up, and You Should Be, Too

iDietology is where diet meets ideology. I know, because I just made up the word. It's rather toxic food for thought, there is way too much of it around, and I advise you to sustain yourself on better fare.

As you might expect, I have a large and diverse array of correspondents on the topic of diet and health. Many seek my opinion, others seek to share their own. In most cases, there is the benefit of dialogue -- the blend of both commenting and listening, giving and taking. Almost all dialogue is good dialogue, so I welcome such exchanges.

But among my frequent interlocutors are those who speak but don't listen. This group, thankfully a minority but quite large enough to be noteworthy, is on a mission. In each case, the individual in question -- some professional, some not -- is convinced that he or she has found the one great truth about nutrition and health. And he or she floods my inbox with that particular opinion and the evidence to support it.

One such correspondent is convinced that the single thing most wrong with our diets is an excess of omega-6 fats. He seems to believe in general that our diets went bad only after we fixated on cutting fat in the 1980s -- (Editorial note: People tend to forget that we were already in trouble before we fixated on cutting fat, which is why the public health authorities were desperately seeking an alternative to the status quo, whether or not they got it quite right) -- and that in particular, we have been egregiously wrong about saturated fat being harmful. His contention is not that there isn't a particular bad actor, but that we settled on the wrong one. His fixed position is that an excess of omega-6 polyunsaturated fat is, in fact, guilty of all the crimes against humanity for which saturated fat has been wrongly convicted.

To be quite fair, this gentleman is obviously well-intentioned, clearly quite intelligent, and very passionate about his cause. Nor is he cavalier in his efforts. His emails to me are rich in both detail and citations.

And yet, he is wrong. He is wrong both in both message and method. I'll come back to that.

First, let me note that I have another correspondent -- equally passionate, equally intelligent, equally educated, and so on -- who is convinced that animal products are the one true problem with our diets, and health. This person's notes to me are every bit as detail- and citation-rich as the other, but the message is entirely opposed. There is no concern here whatsoever about omega-6 fats from plant foods, but rather passionate objection to the false exoneration of saturated fats and cholesterol. This person cites study after study to substantiate the case that vegan (or at the very least, vegetarian) diets are the only one true way to eat well, and that all that ails us resides in animal foods and the nutritional hazards, saturated fat noteworthy among them, for which they serve as vehicles.

These two will suffice to represent the many others who engage with me on similar terms, some arguing always and only about the merits of Paleo diets; some about the glycemic index; some about sugar; some about dairy; some about protein; and so on.

The trouble in each case is that the argument made is a product not of true scholarship, but of an echo chamber. In an echo chamber, a particular message reverberates to displace all others. The capacity to hear what else is going on in the world is lost; a selective deafness sets in.

This phenomenon is not only well-established but well-documented as one of the modern world's great perils. In Going to Extremes, Cass Sunstein demonstrates in vivid detail how echo chamber isolation -- sequestration, in essence, with the ideas you already own and others who share them -- leads to confrontational fervor, religious radicalism, and terrorism.

To most of us, the idea of strapping explosives to our torso; wading into a random crowd of men, women, and children; and wreaking lethal carnage is both anathema and insane. Yet, people with no history of genuine mental illness commit such acts. How? They are often products of echo chambers. A particular world view -- encompassing who did what to whom, what should be done in retribution, and how the Almighty will feel about the whole thing -- is repeated over and over among likeminded people, sharing a sense of victimization. The message swells to occupy the entire range of audibility; nothing else is ever heard. The bloody mayhem that ensues makes perfect sense in context.

But the context is, of course, deranged. The number of times a message is repeated does nothing to make it right. The volume of a clamor does nothing to make it true. The exclusion of other views and perspectives does nothing to belie them.

Thankfully, thus far at least, the diet wars have not to my knowledge devolved to literal violence, although I have been prompted to worry about it. Thus far, rhetorical violence prevails.

But that's bad enough. The superimposition of ideology on our understanding of diet and health creates a world of echo chambers where everyone speaks, but no one listens.

The selective pursuit of information to validate the position you already hold is not scholarship; it is self-indulgence. The dedicated effort to propagate that view is not intellectual exchange; it is proselytism. The intentions may be good, but frankly -- who cares? In the enclave of their own echo chambers, even suicide bombers are convinced of their good intentions. While good ends do not invariably justify all means, certainly bad ends reliably unjustify them.

My own views about diet and health are a matter of public record, playing out across countless columns like this one, as well as the pages of peer-reviewed articles, chapters, books, and interviews. First and foremost, I am committed to resist falling in love with any position; if the science changes, so too will my views (as, indeed, they have over the years -- albeit incrementally). Second, I am committed to reading the relevant science and assessing its merits whether I like or dislike the message. What I like is inconsequential; what matters is the weight of evidence. The hard part of homework, and thus the most productive part, is scrutinizing and judging fairly the opinions you don't already own, and the cases for them.

Because I am human, I no doubt have my biases, strive though I might to be immune. But one of my strongest biases is against bias, and the methods that propagate it. My interest in diet and health is rooted in epidemiology -- evidence of what happens to real people in the real world -- not ideology. I don't have a diet to sell.

And on that basis, I contend again that no one thing is the thing wrong with modern diets. No one food, nutrient, or ingredient is our nemesis or panacea. There is much we don't know, but we are very far from clueless about the basic care and feeding of Homo sapiens. We absolutely do know the basic theme of eating for both optimal health and weight control; we absolutely cannot say which exact variant on that theme is decisively best. We can fortify the argument for a mostly-plant based diet further if we factor in considerations of water consumption, the treatment of other species, and conservation -- as we really must. People lacking an arable planet will find it hard to eat well no matter what their appetites, and we are driving ourselves ominously in that direction.

Please join me, then, in renouncing iDietology. Radical fervor and echo chamber distortions do quite enough damage to our world without populating our kitchen tables. Be fed up, as I am, with such nonsense -- and we will all wind up eating better.


Dr. David L. Katz has authored three editions of a nutrition textbook for health care professionals. He is editor-in-chief of the peer-reviewed journal Childhood Obesity, and President of the American College of Lifestyle Medicine. He was commissioned by Annual Review in Public Health to write the review article, Can We Say What Diet is Best for Health? He is the author of Disease Proof, and most recently, of the epic novel, reVision.