When did God first give humans permission to eat meat?
God first granted humans permission to eat meat after Noah and his sons came off the Ark. At that time, God established human government and gave mankind permission to kill and eat the flesh of animals, a permission they had never been given before.
Les explains that when Noah and his three sons and their wives came off the Ark, all circumstances were totally different from the Garden. God was dealing differently. Even to the point that God would establish human government to restrain murder and crime. On top of that, He gave mankind permission now to kill and eat, and eat the flesh of these animals. They never had that permission before, so it was a whole different set of circumstances. This contrasts with later developments, such as God calling Abraham out of pagan people, and after about 500 years giving Israel the Law, which had never been before.