Diet: If We Can't Be Right, Is There a Best Way to Be Wrong?

Diet: If We Can't Be Right, Is There a Best Way to Be Wrong?

David Katz 30/01/2019 4

Predictably, and yes, sadly, the publication of the EAT-Lancet Commission Report on “healthy diets from sustainable food systems” by a large, multidisciplinary, multinational group of world-leading experts ran immediately into discrediting criticisms, generally by far-less-qualified commentators. Some such whingeing, in places like “Beef Magazine,” are too dismissible to bother dissecting. But others- in places like, for instance, Psychology Today - might appear less so.

But are they, really? Consider how easy it is for a theater critic who has never, and could never, make a movie, direct a movie, or act in a movie, to “dislike” a movie. Now consider that in the diet world, things go a step further: the “theater critics” of the diet world need never even have seen the movie; they simply cite another critic with whom they want to agree. The result is that vast volumes of highly consistent science about diet and health are equated with a few critical commentaries by people who have generally contributed nothing to those vast volumes.

This is how we can actually know so much about diet and health and talk ourselves into the pertinacious impression that we are forever confused. We are not, and I make that full case- what we know, how and why we know it- across the ~750 pages of The Truth About Food. Importantly, I wrote that book on behalf of The True Health Initiative, a global coalition of hundreds of leading experts and influencers on diet, lifestyle, and health from over 40 countries, ranging in personal inclinations from Paleo to vegan, and everything in between. All book proceeds go to support that initiative, a federally authorized 501c3 non-profit. The below is excerpted/adapted from the book (pp. 623-627 of the paperback version, to be exact). Let’s call it: “If We Really Don’t Know What’s Right About Diet, What’s the Best Way to Be Wrong?


We don’t know everything about diet and health, of course, and we don’t know anything with truly perfect certainty. But we know more than enough to add years to our lives, and life to our years; we know more than enough to succor the planet into the bargain. And we know it with very, very, very, very, very, very considerable confidence.

But before I tell you that truth: what if we didn’t know it with very, very (you get the idea…) high confidence? What if we actually were- as whiplash-inducing headlines so often suggest- substantially befuddled about the proper care and feeding of Homo sapiens? What if we TRULY had cause to wonder whether more beans, or more beef, would serve our health better? Let’s explore the implications of such extreme doubt, before I go on to tell you how extremely implausible it is.

While I am quite confident about the fundamental truths of diet for good health, I concede readily that am not absolutely, incontrovertibly certain about much. In the company of the wisest, most thoughtful, most expert and knowledgeable people I know- I have many legitimate doubts about many details of nutrition. 

I am perfectly comfortable with these uncertainties. I have long subscribed to the view best expressed by Bertrand Russell: The whole problem with the world is that fools and fanatics are always so certain of themselves, and wiser people so full of doubts.

Let’s allow for the wisdom of doubt, then, and consider all the times some new study has roiled if not the nutrition world, at least its representation to the public. Such articles, which I have reviewed at length any number of times, effectively part dietary perspective like Moses allegedly did the Red Sea: to one side, there is advocacy for more plant foods (vegetables, fruits, legumes, whole grains, nuts, and seeds); to the other, there is advocacy for more animal foods (meat, butter, cheese, eggs) and more animal fat. I am decisively in the former camp.

Just in case it isn’t obvious, the fight doesn’t always sound like “more plants” versus “more meat.” Sometimes the focus is on sugar versus saturated fat (news flash: excesses of both are bad!). Sometimes the focus is on macronutrient levels, and whether more dietary evil resides in the wrong fats, the wrong carbs, or the wrong kind of protein. Still, the biggest rift these days, encompassing those others to some extent, is: more plant foods, or more animal foods?

What the allowance for doubt tells us is that if, in fact, the evidence is insufficient to be absolutely certain that one of these is right- then we cannot be absolutely certain that the other is right, either. Let’s pretend the playing field is level; let’s give all the same benefits of all the same doubts to all the members of both camps. I am not entirely sure that’s deserved- in fact, I doubt it- but let’s toss the benefit of that doubt into the pot as well.

It all leaves you with a choice - now, and whenever you hear the latest “news” about nutrition. You can risk being wrong in one direction, or you can risk being wrong in the other.

Let’s say that those of us recommending more whole plant foods, and a dietary pattern in which they predominate, are wrong. What are you risking by listening to us?

Well, we know that all of the world’s longest lived, most vital peoples discovered to date eat this way. So even if we are wrong about whole foods, mostly plants being best for your health- they are clearly compatible with it, as measured by what matters most: both years in life, and life in years. At worst, you wind up eating in a way that is entirely compatible with the best of health, even if not explicitly the reason for it. At worst, you wind up missing out on some foods you might otherwise enjoy (although that’s generally a minor and transient matter, because over relatively little time, you are apt to learn to love the foods you are with).

That’s it. That’s the consequence of choosing to go with the “more plants” camp, if that camp- my camp- is, in fact, wrong.

What are the alternative risks of listening to the “more meat” camp, if that camp is wrong? Well, none of the longest lived, most vital peoples yet discovered eat meat predominant diets, or diets high in saturated fat. (None of them eat diets high in added sugar either, by the way.) So if this camp is, in fact, wrong- then it’s possible that their advice is actually incompatible with the health outcomes that matter most: longevity, plus vitality. If this camp is wrong, you might be increasing your personal risk of disease and premature death. To be clear, I am not saying (at the moment) this is true; I am simply noting that if the “more meat” crowd CAN be wrong, then this COULD be the implication for your health of listening to them. There is no clear indication in real-world experience that this lifestyle choice even CAN lead to the desirable extremes of longevity and vitality.

But that’s the least of it, really, because if you do get coronary disease you will probably find some cardiologist to clean out your arteries; you get to have your disease, and make it chronic, too. Modern medicine is not very good at making people healthy- only lifestyle, and the social factors underlying it tend to do that. But modern medicine is often quite good at making disease chronic by forestalling death.

The consensus among environmental scientists about meat and dairy is even greater than that of nutrition scientists. Producing plants to feed animals to produce meat for human consumption uses vastly more water than producing plants for direct human consumption; beef, compared to almost any other food, is literally off the chart (in the company of chocolate). Producing meat, and dairy, makes massive contributions to greenhouse gas emission. 

So, unless all of the environmental scientists- experts in everything from life cycle analysis to conservation, sustainable agriculture to biodiversity- are wrong, too, then listening to the “more meat” camp and being wrong means potentially devastating effects on the world’s climate, ecosystems, and aquifers. It means less water to drink, but more floods. It means more droughts, stronger storms, and ever more frequent extinctions. In contrast, if the “more plants” camp is wrong about the best diet for health, listening to them will almost certainly confer diverse environmental benefit.

And, finally, there is the matter of ethics, decency- and what we ironically call “humane” treatment. If the “more plant” camp is wrong about what’s best for your health, listening to them will nonetheless reduce the cruelty and abuse perpetrated on vast populations of animals that think and feel an awful lot like the dogs, and cats, and horses so many of us love. If, however, you listen to the “more meat” camp and they are wrong, then ever more such animals will be subject to cruelty, abuse, and often traumatic death- in the service of making your diet worse for you, too.

Let’s summarize. If the “more plant” message is wrong, then the worst-case scenario is that it’s still compatible with optimal health (just not necessary for it); still massively beneficial to the environment and planet (unless all of the environmental scientists are also wrong); and massively conducive to the kinder, gentler treatment of our fellow creatures (unless…well, nothing. Period).

If the “more meat” message is wrong, then the worst-case scenario is that it may be incompatible with optimal health, and listening to it may potentially take life from your years, with or without taking years from your life. Along the way, you will almost certainly be contributing to environmental degradation, aquifer depletion, global warming, and cruelty to animals at an industrial scale.

None of this says that one camp is right and the other wrong. It simply stipulates that if we really have cause to be uncertain about fundamentals of nutrition, then what’s good for the plant-loving goose should be good for the meat-loving gander.  Human fallibility is non-denominational.

And, presumably, you- like the rest of us- are not infallible either. So if obligated to eat despite the routinely broadcast doubts about diet and health- perhaps the best you can do is choose how you would rather be wrong.

At least, that would be the best you could do if the doubt really were that great. It’s not. 


That tale continues in the book (on p. 627, to be exact). For now, our work here is done.

Dr. David L. Katz

Author, The Truth about Food. All book proceeds go to support the True Health Initiative, a federally authorized 501c3 non-profit.

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  • Myles Burton

    Thoughtful read

  • Steve Wright

    Very pleased with your educational guides

  • Lauren Clark

    I still can't belive people actully eat and digest meat.

  • Andy Savage

    While truly there's any value in taking baby steps in any diet, I am so excited this article exists.

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David Katz

Healthcare Expert

David L. Katz, MD, MPH, FACPM, FACP, FACLM, is the Founding Director (1998) of Yale University’s Yale-Griffin Prevention Research Center, and former President of the American College of Lifestyle Medicine. He has published roughly 200 scientific articles and textbook chapters, and 15 books to date, including multiple editions of leading textbooks in both preventive medicine, and nutrition. He has made important contributions in the areas of lifestyle interventions for health promotion; nutrient profiling; behavior modification; holistic care; and evidence-based medicine. David earned his BA degree from Dartmouth College (1984); his MD from the Albert Einstein College of Medicine (1988); and his MPH from the Yale University School of Public Health (1993). He completed sequential residency training in Internal Medicine, and Preventive Medicine/Public Health. He is a two-time diplomate of the American Board of Internal Medicine, and a board-certified specialist in Preventive Medicine/Public Health. He has received two Honorary Doctorates.

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