@cadey @tomas @mmn well, there's two factors in my view: ethic and sustainability.

1. Plants AFAIK can't feel pain or suffer in any way. They do respond to certain stimuli but it's not to avoid suffering, but just to survive and grow in a better way.
2. In order to eat animals and/or their by-products (since there's no other alternative beyond veganism), more plants are necessary because these animals need to live, walk, breath, keep themselves warm, etc. (I can explain it in entropy terms if you want)

If you want more information just let me know :)