Please lets stop Protestantizing our reading and understanding of the Bible and let us stop selectively snipping verses to support our points.
Firstly, the Catholic understanding and interpertation of the Bible is that it is the literal Word of God as understood through human facualties, because God is a Mystery that can never be fully grasped. Scripture is always true, but not always factual, and such was the case until Martin Luther decided it should be otherwise.
Secondly, we do not need to wait for something to be reference in the Bible to believe that it only occurs from the point at which it is referenced, for instance, There is no mention of sacrifice until Genesis 4:4. Does that mean there were no sacrifices before Abel and Cain? God didn’t ask for it so how did they know to make the offering.
Also, that kind of reading and understanding, negates the truth that “God is the same yesterday, today, and forever” – “As it was in the beginning, is now and ever shall be.”
Furthermore, such methods facilitates a false conflict between faith and science.
Now for my answer:
In Genesis 1:28, God gives Adam and Eve dominion over the fish, birds, and all living things.
Dominion equals the power of life and death, therefore the power to kill and eat.
In Genesis 1:29, He In Genesis 1:29, He ALSO gives them all the plants to eat.
So from the beginning we were omnivores, eating both plants and animals.
Furthermore, Genesis 4:2 states that Abel was a keeper of flocks. Why keep flocks if not for food.
We must also keep in mind what a sacrifice is. It is firstly an acknowledgement that all things belong to God. Secondly, it is communion and consumation with God. Acceptance of the sacrifice is an affirmation of His love, and thus God shares with us His bounty.
Abel sacrificed from his flock, and it was acceptable to God. Therefore, Abel and God shared the consumation of the sacrifice – Abel and God ate the flesh of the animal together.
That is why Abel is referenced in the Eucharistic prayer, "Be pleased to look upon these gifts with a serene and kindly countenance, and to accept them, as once you were pleased to accept the gifts of your servant Abel the just…"
Since the Mass is a directly connected with the Heavenly Feast, when we are consuming the Blessed Sacrament, we are consuming the flesh and blood of Christ, as is the Trinity, and all the blessed at the Heavenly Altar.
So if we go back to when God walked with Adam and Eve in the Garden, we should understand that Adam and Eve were in full communion with God; that Adam and Eve knew all things were God’s, which they acknowledged in sacrifice, and that they consumated God’s gifts with Him.
God and Adam and Eve ate together from all that was in the Garden, of plants and of animals.