When did God give man permission to eat animals....?

I am curious about this as I am making changes this year toward a vegetarian diet. I thought the following passages supported this:

"I give you every seed baring plant on the face of the whole earth and every tree that has fruit with seed in it. They will be yours for food". Genesis 1:29

and then after the flood..........

"Everything that lives and moves will be food for you. Just as I gave you the green plants, I now give you everything. But you must not eat meat that has its lifeblood still in it". Genesis 9:3-4

What does it mean "lifeblood still in it"? I took that to mean animals with blood coursing through veins.

"And for your lifeblood I will surely demand an accounting. I will demand an accounting from every animal. And from each man, too, I will demand an accounting for the life of his fellow man."

What does that mean...demand an accounting from every animal?