Food For Thought: Facts and Myths About Mankind Being Omnivorous vs Herbivorous

Full disclosure

I’m a meat-eater and have never entertained going vegetarian/vegan. My passion level on the subject is pretty low, it’s just my curiosity that’s high. Unlike me, some are quite fervent on the subject however, so be wary of that if you intend to discuss the subject with those who have chosen to avoid animal byproducts. You may be in for a very heated debate.

While I do have a love for animals, especially my pets, and I understand (and largely agree with) all the arguments against the less-than-ethical treatment of animals, knowing that there are many natural meat-eaters in this world lends me to the conclusion that animals eating others is simply the natural order of things. So those are my biases in advance, and you should be fairly made aware of them.


I would also like to point out that ALL decisions about your health and diet should involve consulting your physician (MD) and/or a registered dietitian (RD). I’m neither of those things. Do NOT consider my advice, or any other internet celebrity who isn’t an authority on the subject (aka The Food Babe, David Wolf, et al.) as a credible source.

I’m merely a skeptic providing food for thought, not giving any dietary advice above consulting your doctor or dietitian.

Unlike the aforementioned celebs, I will at least cite reputable sources where possible. All of them are chocked full of great information. They’re not just there for reference, I encourage you to read them individually. I’ve even reached out to a few registered dietitians as well, to be sure I don’t steer you down the wrong path (as you’ll see later).

On to the show…

To start, let’s break down veganism vs. vegetarianism. The short answer is that vegetarians don’t eat meat. Vegans take that one step further, and don’t consume anything that comes from animals, such as meat, dairy, eggs, and other such animal-derived consumables. For the long answer, click this article from Authority Nutrition.

There are two basic types of reasons for choosing to drop foods from the animal kingdom—opinion-based and factual. Only factual claims could be fairly subjected to criticism.

For instance, if you don’t want to be part of exploiting animals in any way, that’s a matter of opinion. While others can potentially find flaws in your reasoning, the bottom line is that opinions, by definition, are not right or wrong. So if that’s your only motivation, no one should be trying to argue you’re right or wrong, only that they agree or disagree.

The other reason one might do so, is for health reasons. That is a matter of fact, not opinion, and therefore is subject to scrutiny. No one has a right to their own facts, nor do facts care what someone believes. The best way to come  to know them, is via the scientific method. So this is why I stress above that someone trained in evidence-based science like an MD or RD should be consulted. It is your life, after all…so to you, it’s kinda a big deal.

Controlled studies are difficult on the subject, you have to rely on the subjects not only to stick to their respective diets, but if done properly, the study would take decades to test for longevity between the two groups, and other factors like changes in exercise and lifestyle, changes in diet within the framework of omnivorosity and herbovosity can all change the outcome and skew the data in such a study.

That being said, I was able to find this study from Oxford, which studied vegetarians against omnivores. As you can probably imagine, it’s complicated, for reasons I’ll get into in a bit. I’ll let you read it and come to your own conclusions, I’m not qualified to do so myself. (I keep pointing this out, not to demean myself, but so you don’t take advice from others who aren’t qualified either.)

So what started me down this path of inquiry? I had an exchange with a friend who is vegan, and she had suggested that dairy was not a natural food source for humans—I’ve heard this multiple times since. Me being the slightly sarcastic skeptic that I am, decided to share the response I gave her recently on Twitter for a laugh or two.

While I was of course being a little cheeky in my response, this brings me to my first point. There are a lot of clearly false claims out there that simple skepticism on your part can debunk—no biology degree required. Question everything, especially when your health is at stake. So let’s get to this claim.

Milk – It Does a Body Good?

All mammals are born eating milk. Mammals have mammary glands which supply…you guessed it…milk! And yes, I said eating—milk is technically a food, as much as it is a drink.

Why do we consume milk? Remember back to the days you were born; in case you don’t recall, you didn’t have any teeth.

Since our prehistoric ancestors didn’t have access to baby food or applesauce, it should make sense that milk was pretty much the only thing a toothless fecal factory can consume and get all the nutrients it needed. So, voila! We are in fact meant to eat dairy; or more to the point, the nutrients contained in dairy.

While it’s important to note that milk does vary slightly from animal to animal based on their needs (cow’s milk isn’t evolved for humans, for instance), there’s certainly no evidence it’s toxic in any scientific definition of the word. Click here for a good breakdown of the nutritional content of many animal milks from the University of Illinois. You’ll notice that it’s largely the same contents, just in varying amounts. This make sense, because we’re all mammals, and on the evolutionary tree, we’re all one big branch stemming from one common base, which means our needs are pretty similar as well.

Wisconsin milk board overstates dairy’s benefits to children, some experts say – Click Image for Article

As we grow older, and our teeth come in, we don’t need milk—we never technically did. We just need nutrients that milk provides, which many other chewable food sources also contain. Your body doesn’t care where protein, glucose (sugar), sodium chloride (salt), calcium, and other essential vitamins and nutrients come from, it just needs them wherever you can get them. So if one is to argue you need milk as you grow older and are able to consume a more normal diet, that’s also pretty false, despite what the National Dairy Council tells you. Milk does however have a good, natural combination of carbs, fat, and protein which is why it’s been deemed a great beverage for post-exercise recovery.​

Harvard has a phenomenal write-up on milk, including it’s effects on osteoporosis, one of many dubious claims about it. As you can probably imagine, as with most things, there are pros and cons—be skeptical of anyone telling you anything is all good or bad.

There’s a saying in biology “everything is a poison, what matters is the dose.” Bear that in mind, because many false arguments come from a zero-tolerance perspective (the idea that consuming any amount is dangerous), which is rarely if ever true. How much of something you consume is almost always equally important to what you actually consume. You can die from drinking too much water, while there is an acceptable amount of substances like mercury you can safely consume without incident. This is important for all those who think glyphosate and other potentially harmful chemicals used in food crops should learn before they assume what they’re eating is dangerous. The levels you get them in with a normal diet, make them almost entirely innocuous.

Since I’m a lover of science, and my interest level was getting high, I tweeted the following to two RDs I know from Twitter. Huge thanks to Amanda Kruse RD, CD (@Amanda_Kruse) for editing this post, and thanks to RD David from Science Based Nutrition (@SciBasedNutr), and Cara Harbstreet RD (@StreetSmartRD) for furthering the discussion on Twitter. I encourage you to follow them and join in the discussion.

Human Evolution

One of the arguments against eschewing meat, is that we evolved to eat it. It’s true humans have been eating meat for the entirety of our 200,000ish years on Earth. To argue we aren’t evolved to eat meat is clearly illogical. Veganism/Vegetarianism are fairly new concepts to our species.

The Cleveland Clinic

A very good short introduction to going meatless from the Cleveland Clinic shows what precautions one should take if going vegan/vegetarian to get nutrients they’ll be missing from a normal diet containing meat. If special caution needs to be taken if you ween yourself off of meat, this itself is a pretty strong argument that we are meant to be omnivorous. But if choosing this route, here’s a separate article from Cleveland Clinic (thanks Twitter RDs) outlining what you should consider—it can be a very good alternative for some if done right.

On the flip side, this article from Harriet Hall from Science Based Medicine is a pretty good account of the many pitfalls one might experience by going vegan. It’s a science-based review of a book from a woman who went vegan, only to realize she was experiencing health issues as a result.

Vegetarian Tostadas

But, as the articles from Cleveland Clinic point out, with some careful planning, you can easily substitute those missing nutrients with plant-based options. In doing so, you can fashion a diet that may in fact be even healthier. So while the evolution argument is compelling on the face of it, the fact remains that you can go meatless and be healthier for it. Take care though; if you think you’re not the type to stick to a carefully planned diet, veganism may not be for you.

So why would we be meat-eaters in the first place?

Evolution is the ability for a species to adapt to its environment. So they will thrive in locations that contain a rich supply of foods and nutrients those species need. If that species can eat just about anything, then that species has a greater chance of living on. So being omnivorous gave mankind the best chance of survival as we migrated all around the globe.

Mankind is also the one species (there may be others, but I’m not aware of them) that took evolution to a whole new level by customizing their environment to suit them. We build fires and air conditioning units. We farm and build shelter, too. All of these things make it possible for us to inhabit every continent on the planet. Take that, other species!

This ability to adapt our environment to suit us, changed the face of evolution in a meaningful way. It also brings us full circle to veganism, because it allowed us to do things like go vegan/vegetarian if we choose to, thanks to the knowledge of how we can modify our diet to supplement what we’ll miss from meat.

Bad Arguments

Because this issue is quite contentious, there are a lot of bad arguments out there from people who simply want you to see their side, and through confirmation bias, have come to their conclusions one way or the other—insisting their way is the only way to be.

Anecdotes – “I went vegan, and I feel great. So will you!”

As the BBC’s Dr. Karl Kruszelnicki often says…

So why should you ignore your vegan friend who swears by their diet? Because they are not a controlled study.

Imagine your friend does go vegan for health reasons. Many meat eaters eat fried meats like deep-fried chicken nuggets, and other friend foods like french fries. Maybe they’re feeling bad, and a doctor tells them to eat healthier and exercise.

So instead of entering into a controlled study, they start exercising, and go vegan, as well as other such “healthy” lifestyle changes.

Six months later, they feel great. But why do they feel great? We know that exercise makes you feel better, as long as you don’t overdo it. So maybe going vegan did nothing, and you’re just feeling better because of the exercise.

Also, maybe while going vegetarian, you also cut out those other fried foods as well, so you’re not only going vegetarian, you’re eating healthier in general. It’s quite possible that had you done all that, but instead switched your meat consumption to fish, chicken, bison, and other healthier low-fat meats, you’d be even better. How would you know? You didn’t control for all those variables. Instead, you went through a life change, and introduced a myriad of variables where you really can’t determine which, if any were effective.

So while your friend might mean well, this is a great example as to why scientists don’t consider anecdotes as evidence.

What is healthiest?

Another concern you should have, is when people claim one diet is healthier than the other.

The word healthy is incredibly ambiguous—how would you define it? It could mean not being obese or malnourished, disease free, heart-healthy, mobile, longevity of life, clear of mind with no dementia…the list is pretty endless as to how you could define it. (I refer you to the Oxford study above now, which broke down the areas that were better and worse). So for someone to claim one is healthier than the other as a blanket statement, is already a walk down the path of hyperbole and flawed logic.

Because of nearly entire lack of fat, if obesity is your concern, a vegan/vegetarian diet is almost certainly the better option than eating high-fat meats. But again, lean meats like chicken, fish, bison, etc., could achieve the same goal.

Why do I point this out? Because again, this is exactly why you should consult your doctor, or a registered dietitian. They will know better than anyone, how to determine your needs, and then guide you down the best path to achieve them.


Whether you choose to go herbivorous or carnivorous, there are healthy and unhealthy paths you can go down with either. Ignore anecdotal evidence, ignore hyperbolic claims that indicate one is clearly “healthier” than the other, ignore your well-intentioned friends who are eminently unqualified, and the myriad of internet celebrities selling you whatever they want to believe, too. With most things in life, there are pros and cons; anyone telling you there isn’t, is someone you probably shouldn’t listen to.

You can go vegan and be healthier. You can remain omnivorous and with small changes, still be healthier. While we did evolve to eat meat, at the end of the day, it doesn’t appear it’s necessary. The short answer seems to be, that the opinion reason is the only one that’s a firm reason to ditch meat. You can achieve most any health goals without going vegan by…say it with me…consulting your doctor or registered dietitian.



2 thoughts on “Food For Thought: Facts and Myths About Mankind Being Omnivorous vs Herbivorous”

  1. Birds. Not just for eating, they also modify their environment. It’s called a nest. Rodents dig tunnels. Insects(think ants) not only build colonies but some species farm fungus and even keep livestock (aphids) inside those colonies.

    1. I see where you’re going with that, but not quite what I meant in the context. I could have been clearer.

      I mean that we modify our environment in ways to make uninhabitable places habitable for us. Largely by creating heating and cooling, as well as gardening. The things you’re referring to are mostly just shelter. Not really things that make a place that’s unlivable, livable. In my own mind, they’re different. But nonetheless, good and valid point, Eric. Thanks for your input.

Drop some genius on me here.

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