The Bible presents a different history of the human diet. This history can be divided up into these eras: pre-flood, post-flood, Mosaic, and post-Christ.
Humanity's Diet In The Pre-FloodThe first and second chapters of Genesis explain that the world God created was free of sin and death. There was no bloodshed in the beginning. All people and animals were vegetarians (Genesis 1:30).
Then, in Genesis 3, Adam and Eve were deceived into eating from the tree by the serpent. Humanity fell. Adam and Eve were ashamed of their nakedness, so God made garments for Adam and Eve out of animal skin. Thus, for the first time in history the blood of an animal was shed.
In Genesis 4, more blood is shed when Abel offers up an animal sacrifice to the Lord (Genesis 4:4). Human blood is then shed when Cain kills Abel.
By Noah's time, violence had filled the planet (Genesis 6:11). Human bloodshed was not a rarity in Noah's day, it was the norm. Still, even in the midst of the violence and bloodshed, God had not permitted humanity to eat meat.
Humanity's Diet In The Post-Flood WorldGod permitted people to eat meat for the first time after the flood ended. The only rule given was that meat could not be eaten raw (Genesis 9:3-4).
The Bible's view of man's dietary history contradicts current evolutionary views. While many of today's scientists claim that primitive humans were originally hunter-gatherers, Christians can be confident in claiming that early humans did not hunt. Furthermore, early humans were far from "primitive". Cain, the second man mentioned in Scripture, is said to have been a worker or tiller of the ground (Genesis 4:2). Agriculture was not a later development in human history, but a discovery made at the very beginning.
Humanity's Diet According To Mosaic LawOver one thousand years passed before God again spoke about humanity's diet. In the law that God gave to Moses, He restricted the types of meat that the people of Israel could eat. A list of the forbidden animals can be found in Leviticus 11.
As a side note, it is possible that these animals had already been forbidden. People as early as Noah knew of a distinction between clean and unclean animals (Genesis 7:2). They might have, perhaps, assumed that this meant they were not to be eaten. Regardless, unclean animals were not explicitly forbidden by God until Moses' time.
Humanity's Diet In The Post-Christ WorldAbout 1500 years after the institution of the Mosaic Law, God again spoke about the human diet. This time, God spoke to the Apostle Peter in a dream, telling him that he could now eat previously "unclean" animals. This news shocked Peter, and God had to repeat the dream two more times for Peter to believe it (Acts 10:9-16). Peter's reaction to this dream indicates how deeply the prohibition of unclean animals was rooted in the Jewish consciousness.
Today, Christians are free to eat of any animal, both unclean and clean. The only prohibition remaining is the one that God gave to Noah: not to eat animals raw (Genesis 9:3-4).
The Future of Humanity's DietThere is a good chance that the prohibition against eating meat will return. In the New Heavens and the New Earth, there will no longer be any death— ever (Revelation 21:4). Therefore, no animals will be slaughtered, which means that no meat will be available (unless God provides a different, painless and deathless way to obtain it).
This change, however, should not be a cause for disappointment. Why? Because whatever we eat while living on the New Earth will surely be more satisfying than anything we've tasted on this fallen planet!
Then the angel showed me the river of the water of life, bright as crystal, flowing from the throne of God and of the Lamb through the middle of the street of the city; also, on either side of the river, the tree of life with its twelve kinds of fruit, yielding its fruit each month. The leaves of the tree were for the healing of the nations. (Revelation 22:1-2)