Think of a natural community of wildlife, such as those on the plains of Africa. Probably the image that comes to mind is huge herds of antelopes, wildebeests, and zebras, with lots of giraffes, a bunch of elephants, and circling around a couple lions and a pack of painted dogs. In any community, prey far outnumber predators: herbivores outnumber carnivores.
There cannot be too many predators lest predators eat more than an environment can sustain. The rule is 10:1. Ten units of food produce one unit of energy, so ten units of grass produce one unit of zebra energy, and ten units of zebra energy produce one unit of lion energy, so one unit of lion energy is one hundred units of grass. For this reason, predators are scarce.
Predators usually attack animals smaller than themselves. To take down large prey, smaller predators hunt in packs; think of wolves and dingoes. But because of the energy conversion restriction, large predators cannot form large packs. A pride of lions may have ten lions all told. Even a wolf pack has only about that number.
Large packs or herds appear among herbivores; again, think of those endless herds of large mammals on the African savannah, or troops of dozens of baboons. Large carnivores do not band together; big herds of large animals are herbivores (I am discussing life on the land; porpoises may hunt fish together.)
I am using the terms carnivore and herbivore conveniently. All animals are omnivores. No carnivore is 100% carnivorous, no herbivore is 100% herbivorous. Tigers eat grass from time to time, and even a panda or a koala eats the occasional bug or shrew amongst the leaves. Carnivore and herbivore refer to the balance of diet; no need to be pedantic.
The human being is a large animal. We are larger than 99% of all species of life on earth. The natural grouping for human beings is about 150 persons in one group; in other words, a much larger herd than arises among carnivores. To drive the nail home: large carnivores do not form large groups; large groups of mammals are herbivores. This is just one of many observations that point out what you should be stuffing your face with: nature designed you to be a vegetarian.
Because of the Great American Steak religion, Americans in particular like to see a past peopled by The Great Hunter striding across the Pleistocene clubbing animals to eat. In truth, the diet of human beings has never been predominantly carnivorous, excepting Inuit. Meat has always been eaten sparingly, mostly as a status meal, with the bulk of the diet procured by women out gathering.
But consider the Inuit meat diet: in the Artic before the 20th century, the seals, whales, and fish Inuit ate were entirely free of chemicals and pollution, and did not have the kind of fat domesticated animals (excluding you and me, naturally) develop. Try to find any meat today that is free of ghastly chemicals and toxins.
Plants may have been sprayed with pesticides, but investigations comparing the most polluted vegetables with the least polluted meat show the meat carries 40 times more chemicals than the plant.
Obviously, you are free to eat whatever you please, nails and ground glass if it takes your fancy. But if you want good health, figure out what nature designed you to eat: vegetables, grains, fruits, and nuts; nothing with a face. You want to know what good health is? Knock off the meat.