we weren’t allowed to eat meat until after the flood, no surprise here.
That was the time of the first quotation of a divine affirmative statement in scripture about it; however the concept of animal sacrifices was much older (it was the point of friction between Cain and Abel), and the use of skins was obviously deemed okay. It would be surprising if in such a situation people yet remained vegetarians.
I’d want to know how the whiz kids deduced this. Humans and humanoid animals have traditionally been omnivores.