Earth is a planet that was formed billions of years ago. About 3.5 billion years ago life formed. About 3 billion years ago came the first photosynthetic organisms.

Since then, organisms have been evolving in a worldwide ecosystem built on balance between evolution and resource sustainability. There have been organisms that have thrived based on photosynthesis and other organisms that have thrived based consuming photosynthetic organisms and incorporating nutrients into their own body chemistry. I would probably consider those organisms to be the first herbivores.

Then there are organisms that could eat both the photosynthetic organisms as well as the organisms described above. Those would be the first omnivores.

Over billions of years, complex
Lifeforms evolved and an almost endless spectrum of super complex organisms came into this world developing more and more complex ecosystems. These ecosystems are built on complex systems of exchanges of organic material to propagate life forward. In recent times dinosaur ruled the earth from brontosaurus to the great T-Rex. Even more recent times, like 150 thousand years ago, the first Homo sapiens came into being.

Through the millennia basic structures emerged in these populations of animals. Organs like lungs or gills, the stomach, pancreas, gallbladder, liver, small intestine, cecum, anus etc. These organs are built to facilitate the process of this exchange of organic material that occurs across organisms. They provide a place for the breakdown of food and facilitate the creation of enzymes and hormones that control this process.

Depending on the organism, this combination of organs can be configured in such a way that is better for breaking down fiber and cellulose or better at consuming materials like fats and proteins. It just depends on the animal and it’s place in the ecosystem at a particular time in evolutionary history.

No animal is purely an herbivore and no animal is purely a carnivore. For instance, a tiger primarily eats meat, but you will still see it ripping out blades of grass with its teeth or munching on the stomach of an animal that is full of grass. Even animals like deer or cattle have been known to eat small animals, like an unsuspecting mouse that wanders too close to a cow that is feeding or insects that are hanging out on the blades of grass consumed by cattle.

These examples above show that all animals fall on a spectrum. Nature does not care about life or death or consciousness or any of that. It really doesn’t care about anything. It just “is” and everything evolves in a balance.

Because there are very few to no purely carnivorous or pure herbivores, it is reasonable to say that all animals fall to on a spectrum. Now it is just a matter of determining where each animal falls on that spectrum.

Both humans and chimpanzees come from the closest genetic line about 6+ million years ago. This common relative was an herbivore that primarily survived based on fruit but most likely ate small game. Since then we have evolved in different directions. Chimpanzees went on to eat mostly fruit with a small portion of their diet coming from meat. You can tell this because of their larger rounder gut. This is because they have a shorter large intestine and a longer more voluminous colon/cecum/large intestine for digesting large quantities of fruit and fibrous material.

Humans on the other hand have a smaller more tapered gut. We have a larger small intestine, a smaller large intestine, and a cecum that has evolved away. The reason for this de evolution is because for whatever reason humans shifted more to the omnivorous side. We started to eat more meat and less fruit, roots, etc than our closest relative who still maintained its more vegetarian diet. We stood upright which gave us the ability to use tools and move quickly. We developed the ability to run marathons and sweat, which helped us to hunt in packs and run our prey to exhaustion. We developed the ability to throw a 100 mph fastball, which can be traced back to humans evolving the capability to throw the spear at mammoths and other prey. The ph in our stomach dropped as low as 1.5 so we could eat not only just meat, but rotting meat and marrow from bones, from animals killed by other predators and because we had no refrigeration.

An example of this efficiency of killing can be shown in examples where tribes of humans have run whole herds of wild horses off cliffs or how all the mammoths are now extinct. Or how in Australia there are no large megafauna after 40000 years ago, exactly when people got there.

There isn’t a place on the earth that you can go where animals don’t fear humans. That is because we have killed all animals who don’t know to fear us. My argument is that people are the most effective predator to ever roam the planet. We make velociraptors from Jurassic park look like telatubbies compared to us.

People are not that smart. Everything you hear about the negative affects of meat steams from epidemiological studies that combine people who eat meat with other processed foods such as sugar, bread, starch. They don’t account for people who smoke and use alcohol. The bottom line is that if a person were to eat only meat and organs, they would be absolutely fine. All nutrients that we need to survive can be found in animals. The negative effects only happen when you combine meat with bad food like tons of sugar. Or when you process it. Or when you create it in factories with a lot of antibiotics. Etc.

If a person at only ate grass fed organic meat and organs, it would be very difficult to find anyone with negative health challenges. If someone wants to eat fruits and veggies, I would suspect a diet like the paleo would be best, because in a world of abundance like we have now, people could get themselves into trouble if they eat too much of the wrong plants.

My biggest point is most animals are omnivorous. It just depends on the type of animal. It is definitely possible to live on only plants and also possible to live on only meat. That is the beauty of being human. We evolved to do both.

If we want to try to get into morality, environment, etc. that would be an entirely different discussion with great points on both sides, but I think everyone should be able to agree that humans are not strictly vegan. It’s just not true.

If we wanted to make an argument that it would be good to start shifting over to a plant based diet as a species and give us the time necessary to evolve to it, then that would make more sense to me, but we aren’t there now. that is a discussion that makes sense, but it will be many thousands of years before we would evolve to run optimally on a plant based diet.