The best you can do is read articles saying why meat is good and look at articles saying why meat is bad. Usually everything from one article which isn’t directly contradicted by the other article is fact, and vice versa.
https://www.healthline.com/health/womens-health/childbearing...
And then some science to back it up.
We have cave paintings all over the world of men chasing large animals. That wasn't a game of tag, they are going to eat them. We know the development of cattle culture, fishing societies, etc, all over the world. Even in India, the one traditional society in which a sizable minority (%25) doesn't eat meat, there is widespread evidence of meat-eating prior to the introduction of vegetarianism by the Jains in ~500 BC. But ancient Hindu civilization is much older than that, and prior to this ate meat (and sacrificed animals). All other ancient civilizations: Egyptians, Mesopotamians, Central American societies -- all ate meat, just as their predecessors, the hunter gatherers ate meat.
It is of course not the only thing people ate -- meat in the ancient world was much harder to come by than today and diets varied greatly. But we humans are omnivores, and if people think this is controversial, then they are refusing to face facts about our history.