God created man according to His own image and and He gave to eat every herb bearing seed, which is upon the face of all earth and at the same time every tree, in which is the fruit of a tree yielding seed. (Bible, Genesis 1:29) In this way, in the beginning man became vegetarian. After passing some times, man became corrupt and their wickedness was great in the earth. So He decided to destroy them by bringing devastating flood on the earth. Everything destroyed in the forty days of devastating flood (Bible, Genesis 8:17) but He saved Noah through the boat, and at the same time to Noah’s wife, Noah’s son and their three waives and to every creature that was with Noah.
After devastating flood, nothing was to eat on this earth , nor herb nor any tree. Food was the biggest problem for the man. Then God said – I am giving you every moving thing that have life to eat like the green herbs and tree etc. But do not eat flesh with the life. In this way man became non-vegetarian to follow the God’s word.(Bible, Genesis 9:3-4)