Hi, You are right- When in Eden, they were ‘vegetarians’…then, directly after they came out of the ark…things changed.
And God blessed Noah and his sons, and said unto them, Be fruitful and multiply and replenish the earth.
2)And the fear of you and the dread of you shall be upon every beast of the earth, and upon every foul of the air, upon all that moves upon the earth, and upon all the fishes of the sea;into your hand are the delivered.
3)Every moving thing that lives shall be meat for you; even as the green herb have I given you all things.
4)But flesh with the life thereof, which is the blood thereof, shall ye not eat.
So, that is when the change occurred.