Actually, in the beginning, with Adam and Eve at Creation, mankind was vegetarian. After the Worldwide Flood, God gave mankind meat to eat. But, mankind will return to a vegetarian diet, once again during the world-wide government that Jesus, the Messiah of Israel sets up.
There was no fighting up any food chain. God is the one who set all this up. Mankind had nothing to do with it.
THAT is a mistake that many in this world make, thinking that they (or mankind) are in control, when it is God who is in control!
Of course many animals are clearly evolved predators equipped for hunting and can only eat meat. That’s another hole in the Eden fairy tale.