For most of humanity, humans are mostly plants and seeds. Meat was rare, because hunting is hard, and domesticated crops like grain are a new invention. Like, very new - 10,000 years.

All those were very high in fiber. I believe it's estimated paleolithic humans are over 100 grams of fiber a day, whereas I believe the recommended intake today is 35 grams, which less than 2% of Americans meet.

So yes, the Paleo diet is largely bullshit. No, humans did not eat fatty farmed meats. They barely ate meat at all.