If you’ve ever read any of the popular vegetarian/vegan books out there, then you’ve heard this argument. These authors might say something like… “Humans were never meant to eat meat; our physiology isn’t built for it. Our digestive tract, for instance, is much more similar to that of an herbivore, an animal who only eats plants.” To the average person just looking to eat healthy, this can sound alluring. That’s where I come in and tell you why it’s completely wrong!
Let’s look at some digestive tracts then, shall we? Below are the digestive organs of a human, a cow, and a cat, in that order. Cows are herbivores, eating only plants, while cats are mostly carnivores, and they can derive all the nutrition they need from meat alone. Humans are omnivores, and they lie somewhere in between.
You can see here that a cow, designed to eat grass, has four stomachs (not to mention the spacious interior and giant cecum). If you’re counting, that’s three more than we humans have, and those extra stomachs serve to ferment fibrous plant material for digestion and absorption. Humans don’t have this ability, which is why if we ate grass, it would come out just the way it came in. Ever seen undigested food in your poop? It’s always a plant food right? That’s why.
What humans do have, however, is the ability to produce HCl, aka stomach acid, to break down protein from animal products. Cows and other herbivores can’t do this. Point: we’re not herbivores!
Carnivores like cats, as you can see above, have similar digestive systems to humans. While our physiologies are different, and cats thrive on an extremely high protein/low carbohydrate diet, you can see that we have all the same digestive machinery of an animal designed to eat meat.
Unlike cats, we humans rely on plant foods for needed carbohydrates, vitamins, and minerals. Point: we’re not carnivores either!
Overall, humans take little pieces from herbivores and little pieces from carnivores. We’re unquestionably omnivores; our bodies run best when we feed it both plant and animal foods.
For more information, check out this article here entitled “Humans are Omnivores” (written by a vegetarian!), which goes into much more excruciating scientific detail.