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Are humans natural meat-eaters? Or is switching to a plant-based eating plan safe to do?

Vegetarianism and veganism have both been gaining immense popularity in recent years. Ten years ago, you were lucky if there was a vegetarian option at all. These days, most restaurants and stores have heaps of vegetarian and vegan-friendly choices.

The conversation can get a little… um… heated, let’s say. One of the big questions around whether or not society should adopt veganism full time is this: Did we or did we not evolve to eat meat in the first place?

At Greatist we love taking the big questions by the horns and wrestling them until they tap out and submit the truth. So continuing that great tradition, here’s everything you need to know about homo sapiens and meat consumption.

There’s obviously a lot to unpack with this question. The good thing is, we’re so damn good at unpacking that U-Haul keep pestering us for tips. Let’s get down to it and settle this once and for all, until there’s more science: Are human beings supposed to eat meat?

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Nadine Greef/ Stocksy United

It’s common knowledge that humans are omnivorous. This means that we can consume plants (like herbivores) and meat (like carnivores).

That alone doesn’t tell us very much. Grass is a plant, but we’ve never made a habit of grazing on the same pastures as the cows we turn into delicious steak. Conversely, if you eat polar bear liver you can literally die due to vitamin A overdose. There are clearly rules to this sh*t.

The best way to figure out what we’re supposed to eat is to look at our closest cousins. That’s right, ape enthusiasts — it’s chimp time. Chimpanzees are our closest genetic relatives in the animal kingdom. Some of them tell jokes and everything (and pretty much every single chimp is funnier than James Corden).

It stands to reason that their stomachs are more similar to ours than any other animal strutting around your local zoo. In the wild, our chimp cousins mostly like to chow down on:

  • seeds
  • fruit
  • leaves
  • bark
  • honey
  • flowers
  • insects
  • occasionally, other animals like monkeys or antelope

As you can see, meat isn’t a massive part of the chimp diet. However, it does play a small role — as an occasional dish.

Insects are also a prominent protein source for chimps. While insects don’t count as meat, they are a source of niacin (vitamin B3) and various proteins — the same stuff, coincidentally, that some scientists attribute to us evolving beyond our monkey-brain starter packs.

Did humans eat meat or plants first?

The “to meat or not to meat” conversation wouldn’t be happening (or so fiercely debated) if meat wasn’t so prevalent on our plates. Looking at our close relatives and our own evolution, it’s clear that we bumped up the dead animal part of our diet somewhere along the line.

An important piece of perspective we need is this: Were we herbivores that started seeing red, or carnivores who discovered the joys of fruit and veg?

Vegans can claim the W here. We were plant-munching primates that, through making a habit out of sucking on bones and marrow, evolved a taste for meat about 2.6 million years ago.

However, 2.6 million years is a long time. The proto-humans that shifted from mean weren’t homo sapiens. We didn’t start being our fabulous selves until about 300,000 years ago. So while it’s true that at one point humans were herbivores, the type of human that YOU are has always been omnivorous. You have more in common with Neanderthals than you do our closest herbivorous ancestors.

When did we start cooking meat?

This question is just as important. Cooking meat was perhaps as big an evolutionary leap as deciding to eat it in the first place.

The first record of cooking in general dates back to about 700,000 to 800,000 years ago. Cooking increases the energy humans can gain from meat. Evolution nerds reckoned this development was a huge factor in the homo sapiens‘ evolutionary success.

Meat was already firmly on our menu for a good million and a bit years by then. We also had another 500,000 years to go before we evolved from Homo Erectus (the primate we used to be before deciding we wanted to stand out from the others). So, in short, we’ve done a fair bit of evolving while cooked meat has been on the menu.

While the debate around meat-eating rages on, there is one important factor to consider: We can’t say for certain if Homo Sapiens (i.e., us) can survive without cooked meat long-term. There has never been a point in our evolution when meat wasn’t part of our diet.

First things first: The argument that certain vegan and animal rights activism groups tout, that humans can’t digest meat, is a massive lie.

Yes, we may not have the teeth and jaw structure of raw meat-eating carnivores. There are also a number of health risks associated with meat. That doesn’t mean we can’t digest it though.

The human digestive system produces a buttload of pancreatic enzymes that exist solely for digesting the proteins and fats found in meat, like pepsin.

Bile production in the gall bladder also supports the digestion and absorption of animal fats. This is another key sign that the human body can digest meat.

The simple answer is that we digest meat the same way we digest food that isn’t meat. Our GI tracts have different tools for different fuels. We have a whole bunch of enzymes and digestive chemicals that exist specifically for meat, and they wouldn’t be there if we weren’t supposed to digest at least *a little* animal flesh.

Look at it this way: meat has been a staple part of our diet for hundreds of thousands of years, as we’ve seen. If our ancestors couldn’t digest it, none of us would be here.

We’re not saying you should or shouldn’t eat meat — that’s a personal choice. However, we’ve just given you a whole load of arguments from the pro-meat side of the fence. But there are loads of reasons why some people, even super smart science people, say that humans shouldn’t be eating meat these days.

The main argument against human meat-eating, from a purely biological/evolutionary perspective, is that many of the nutrients we gain from meat are readily available in plants. Beans and nuts, for example, are reliable protein sources for those living meat-free.

There’s also the health argument. As we mentioned, a number of health conditions have associations with meat consumption.

Red meat, for example, has links to various cancers and cardiovascular conditions. There’s also an arguable case for vegetarian and vegan diets having significant health benefits like a drop in your all-around risk of mortality. Which is, y’know, mega useful.

But not all studies show the same results, and more research is necessary before we can firmly plant our feet on either side of the fence.

The benefits of a plant-based diet

Some studies have shown that folk on a vegetarian or vegan diet are at lower risk of diabetes, cancer, metabolic syndrome, and high blood pressure. Even if historically we have eaten meat, the evidence is pretty clear that nowadays you can be healthier without.

There has been evidence that plant-based diets can improve kidney function and male fertility.

However (and this is a big however), we don’t eat the same kind of meat as our ancient cousins. A lot of it is processed and unhealthy. There’s a huge difference between the lean game meat hunter-gatherers consume and Big Macs.

Science still isn’t sure whether planted-based diets provide these benefits because eating plants is super good for you, or if they happen because the super-crappy processed meats are now absent from your diet.

So we know that our ancestors eating meat played a huge part in getting us where we are. But do we still need it to get where we’re going?

Meat gets a bad rep these days. Interest in vegan and vegetarian lifestyles has never been higher. And, with environmental sustainability being a key concern for most, the undisputedly pollution-heavy meat industry is something more and more folk wish to avoid contributing to.

However, lifestyle choices and ethics aside, there aren’t many scientifically-backed reasons to avoid meat entirely. There’s a lot to be said for avoiding processed meats and cutting back our meat consumption for a more balanced diet. This isn’t the same thing as meat abstinence though.

Most meat remains a great source of proteins and many essential salts, fats, and minerals. There’s a reason it’s taken decades to create viable vegetarian alternatives (ask any vegetarian from the 80s for their horror stories).

So long as it’s not heavily processed and doesn’t dominate your plate, continuing to eat meat as part of a balanced diet is still healthy for modern humans (if your ethics and lifestyle leave room for it).

Health risks of veganism and vegetarianism

The main reason humans should continue eating meat is that, for some folk, plant-based diets have to be managed much more carefully.

Sometimes, it’s hard to get the correct nutrient intake from your various meat substitutes, which can lead to all sorts of health concerns. Protein and vitamin B-12 deficiencies are two key risks of a plant-based diet.

Iron, calcium, vitamin D, and fatty acids are other nutrients that can come up short in a plant-based diet. But, there are plenty of meat-free alternatives these days that can make up for the shortfall with a bit of careful dietary planning.

The question of human meat-eating biology is a very loaded part of a heated debate. There are a lot of passionate voices on both sides of the argument, and not all of them are above twisting or manipulating facts to suit their own agenda.

As far as the science people are concerned, the jury is still very much out. There’s strong evidence that our ancestors needed to eat meat to become us (but this is disputed). There’s also strong evidence that eating a plant-based diet in the modern age is healthier (but this is also disputed).

Basically, there’s no fact in this argument we can mention that isn’t disputed (but this is also disputed). However, humans *can* digest meat, and it’s not inherently unhealthy so long as you munch it as part of a balanced diet.