I do think meat was leaner in the paleo days. For example, I don’t know if you ever ate wild game meat like Kudu, Eland, Wildebeest, Ostrich, etc. There is almost zero fat on the meat. But modern meats like beef from cows or lamb meat, are deliberately bred in such a way that their meat is bulky and full of fats, to maximize profits. These are not the same animals that use to roam the earth in the paleolithic age. I’d recommend seeking out lean meats, free-range meats, where the animals are not fed tons of soya grains. You’ll get a better quality meat. Similarly with e.g. picking wild caught salmon instead of factory farmed. It is proven that wild-caught is a better quality meat and this is what our ancestors ate. Not the fatty factory farmed meat we are provided with nowadays. So although your body may have adapted to be able to digest chicken farmed in a small one-foot cubicle, doesn’t mean its good for you.