Why did God introduce animals for man’s consumption after the flood? Clearly that was not man’s original diet. God wanted righteous Noah and his family to live and populate the earth. He gave them the same instruction He gave to Adam and Eve and this time there was a Rainbow covenant where God promised not to flood the whole earth again. God wanted the eight people in the ark to survive and thrive and multiply.
There must have been reasons for allowing meat. Here are two probable reasons why God may have allowed meat in man’s diet.
Even though animals were not God’s original and best diet for man, God allowed man to eat animals in order to survive. It takes time to grow food from seed and finding a fertile area in which to farm may have been a challenge considering the devastation to the earth. Any flood, small or large, creates destruction. Noah and his family could not just go to an area that was not affected by the flood because every part of the earth was changed; they now had to toil to get their food. After devastation to the land the first plants to grow are grasses which man cannot digest. The animals can digest them and thereby provide nutrients for man to survive.
Another possible reason for God to allow man to eat animals is that because of the changes in the earth there would now be places where man could not live if he had only plants to eat. Areas such as the desserts, the frozen tundra or high mountains could not be inhabited without a food supply that did not rely on a temperate climate. Also, as man moved out from the area of Mt. Ararat where the ark landed, there would always be those people on the edge of civilization who would need animal food to sustain them until they organized and settled the area.