What was the situation before the flood regarding law, worship, and eating meat?
Before the flood, Scripture shows there was no law and order and no prescribed system of worship. They could not eat meat; they did not kill anything to eat but ate everything that grew naturally. After the flood, God changed the format and told Noah's family they could kill and eat.
Les explains that God repeatedly changed His format throughout human history, though He Himself never changed. After the Garden, life became different, and then the whole economy up to the flood was also different. Before the flood there was no law and order, no system of worship prescribed, and they could not eat meat. They did not kill anything to eat; they ate of everything that grew naturally. But as soon as Noah and the family came out of the ark, God told them, "Now you can kill and eat."
And God said, Behold, I have given you every herb bearing seed, which is upon the face of all the earth, and every tree, in the which is the fruit of a tree yielding seed; to you it shall be for meat.
Every moving thing that liveth shall be meat for you; even as the green herb have I given you all things.