Answers are seldom better or more informative than the antecedent questions. Tunnels make for poor vistas. Echoes of our own opinions are no substitute for dialogue and a willingness to consider opinions we didn’t already own.

Alas, most of our modern discourse about diet and health has devolved into badly constrained or willfully contrived questions for which there are no good answers (e.g., low fat or low carb?); tunnel vision; and echo chambers.

Our understanding is the poorer for it, and that has evolved into the veritable bane of my professional existence. (I am doing something about that.)

This is not because I am any kind of ideologue wanting my view to prevail; it is because I am an epidemiologue (if I may coin such a term), wanting the weight of data to tip to the favor of us all. It is because I am a Preventive Medicine specialist who knows, these nine years of post-graduate education, 25 years of research and practice, and multiple editions of various textbooks later that we have the readily available means to add both years to lives, and life to years, and squander much of that luminous opportunity instead in perpetual din and discord, and attendant cultural dysfunction.

Perhaps no question about diet and health has become more fraught than: Should we eat meat? Prosecution and defense were both greatly agitated by the recent WHO declaration that processed meats are a carcinogen, and red meat in general.

But no one consideration such as that, however provocative, can answer the general question. If meat “caused” cancer, but produced some countervailing good, such as enhancing brain or muscle development: well, then, should we, or shouldn’t we eat it? The answers competing for our attention are mostly echoing in tunnels, each isolated from the other.

My suggestion is that we exit those tunnels, and take in the view through many lenses, in an effort to see the big picture.

Lens 1: What Do We Mean by ‘Should’?

Our discussions about diet and health go off the tracks and down the tunnels into dark oblivion almost immediately when the word “should” is involved. That word takes on moral overtones, and evokes an image of me—or someone—wagging a finger, admonishing you. I protest that construct, right along with the libertarians among you.

Health is not a moral imperative. (Let’s leave out of this discussion the economics of public health insurance, and the fact that our ill health may burden our fellow tax payers; grist for a different mill.) Health is not the prize, either.

Living the life each of us wants is the prize. Arguably, if a given individual has a “better” life eating baloney sandwiches at each meal and cotton candy for dessert, whatever the health consequences, then that is what they “should” do, since health is in the service of living, not the other way around.

The reality, however, is that healthy people tend to have more fun. I’ve heard a lot of bravado about personal choice and health-be-damned over my 25 years of patient care, but never from people who have lost their health, and most eventually do. The bravado is inevitably from those who have not yet paid for playing. The conversions come fast and furiously in the aftermath of a first stroke or MI, or the onset of diabetes.

I am not interested in telling anyone what to do; but it is my job to tell people what’s what, based on the aggregation of information. To me, any idea of “should” is subordinate to the principle that you are the boss, and only you can determine your priorities.

That said, healthy humans tend to be happier humans. Healthy people do have more fun. When “should” functions in the service of quality of life, as it should, health does tend to emerge as a nearly universal priority.

Lens 2: Evolutionary Biology

The argument is routinely advanced to defend meat consumption that our species, Homo sapiens, and indeed our primate ancestors going back perhaps 6 million years, are constitutionally omnivorous.

We have physiologic adaptations to meat consumption and even, according to some experts, adaptations specific to the consumption of cooked meat.

But this only invites a series of secondary questions. How is the meat of today like, or unlike, Stone Age meat? How is health and vitality today compared to the Stone Age? Since we are omnivorous, what do we know about net effects on human longevity and vitality with a shifting emphasis between plant and animal calories, given an abundance of both?

We know, in fact, that the meat that prevails today is far removed from the meat to which we are natively adapted. We know that life expectancy today is generally twice that, or more, of the Paleolithic mean. We know that humans can and do thrive on diets that are mostly or even exclusively plant-based, and that adaptations to the consumption of both plants and animals means we have choices. Evolutionary biology clearly allows for meat in the human diet, but does not necessarily require it.

Lens 3: Epidemiology/Health

What we know about diet and health cannot exclude the possibility that a genuine “Paleo” diet would be among the variations on the theme of optimal eating for our species, even in the aftermath of the WHO report on meat and cancer risk.

As noted, what we know about the health effects of meat today is based on the meats we eat today, which resemble Stone Age fare very rarely, and even then, rather remotely.

Overwhelmingly, the modern evidence, spanning diverse research methods, populations, geography, cultures, and decades, tips decisively in favor of food, not too much, mostly plants. Free-living populations that adhere, however inadvertently, to this theme monopolize the claim to the longest, most vital lives on the planet. Free-living populations that consume mostly animal products are, in contrast, very rare, and a product of necessity rather than choice. They do exist, however, as illustrated by the Inuit; but are not known for enviable health or longevity. Rather the contrary, unfortunately, for reasons not limited to diet- but clearly not ameliorated by diet either.

Lens 4: Physical Performance

The customary civilities of cyberspace and social media include many insults directed at me for my “plant-leaning” dietary delusions by those who contend, usually on the basis of personal anecdote, that the only way to build lean body mass, fitness, and physical prowess- is with meat.

This simply isn’t true. I am at times tempted to counter such contentions with my own personal anecdote. I am at times tempted to point out the capacity of gorillas, our relatively close cousins, and horses, more distant kin, to build far more formidable mountains of muscle than our own out of plants alone. I am tempted as well to point out the vegetarians and vegans among the world’s athletic elite.

The simple fact is that physiology, not ideology, determines what is required to build muscle. Carnivores do it with meat; herbivores do it with plants. We, as noted, are omnivores. We get to choose.

Lens 5: Cognitive Performance

The focus is above the neck rather than below, but otherwise, the view here is enough like that through lens 4 to say: ditto, more or less.

Lens 6: Planetary Health

Animals eat animals in nature, and it does not imperil the planet. But no other animal has so completely disrupted the natural balance among species. Humans eating meat would not threaten the hospitability of the planet to our children were there billions fewer of us. But here we are, a global horde of more than 7 billion. Having decided not to control our numbers, we now have little choice but to control our appetites. The environmental implications of Homo sapien meat consumption are even clearer, starker, and more urgent than those directed at our personal health.

Lens 7: Ethical Considerations

For our species to declare meat-eating, per se, unethical is rather absurd. Nature has spawned obligate carnivores, and to suggest that Nature is unethical is a blend of arrogance and nonsense. We might contend that it is ethical for animals to eat animals, but not for humans to do so- but that, too, is arrogant nonsense, implying that humans aren’t animals, and are somehow a truly disparate expression of life. We are, rather, part of a continuum of life, and that continuum has long allocated space to animals that eat animals.

That, however, is not the real-world issue. To feed the carnivorous inclinations of a massive, global population invites dubious methods that serve economies, and defile ethical standards. We cannot be 7 billion hunter-gatherers, and thus producing meat for our masses means methods of mass production. Only those who have chosen not to look at such methods are left un-nauseated by them.

For whatever it’s worth, my own decision to renounce the consumption of all mammals many years ago was rather less about farming and more about feelings grown closer to home. At present, four creatures with four legs apiece are among my best friends; three with paws, one with hooves. I couldn’t reconcile making some such fellow mammals members of my family, and others my meal. For reasons of my own, I did what I felt I “should” do.

There could very well be more lenses, views, and considerations. I cannot claim to be comprehensive; I claim only that expanding the view to any degree offers perspective, and clarity. It is perhaps noteworthy that the very same camera with the very same settings will fail for lack of light when attempting a very close shot, but will capture a perfect image when depth of field is expanded. There is, quite simply, more light in a larger frame.

Should human beings eat meat? If we humans were many, many fewer; if our lives were much shorter; if the meat in question were much purer; if our activity levels were much higher; if our methods of acquisition were quick and clean and compassionate; and/or if the resources of the planet were infinite- the answer might well be: sure. But none of those conditions is met in the reality that prevails. In the reality that prevails, the health of both people and the planet, the interests of ethics, epidemiology, and the environment alike- are advanced by humans eating less meat. To the extent that health is our goal, what we replace it with matters, too. I advise against swapping out corned beef for cotton candy.

There is even a case to be made that we “should” eat less meat, in the conventional (and often distasteful) sense of moral obligation. While we are not morally obligated to safeguard our own health, we are, I think we can safely say, morally obligated not to eat our children’s food, or consume our children’s water. We live in a prevailing reality where water is disappearing where it is needed most, and draining glaciers into the sea where we wish it were not. Meat consumption figures in all such mayhem, and thus constitutes a cultural imperative far beyond the limits of our own skin.

In the end, the utility of our questions and answers alike about meat consumption are much related to how we carve up the great beast of our collective uncertainty. Informing our view with only one small part of a larger story will land us in the company of those famously blind men of Indostan. We will be arguing rather pointlessly with one another, oblivious all the while to the havoc being wrought by the elephant in the room, and more importantly, by ourselves.

by David L. Katz For Very Well