I am sceptical of the claim that you cannot grow vegetables (or other plant foods) on grazing lands. If it grows grass and wild flowers how come it is absolutely impossible to grow something else?!! Nowadays we actually grow, water and harvest grass just like we do so with vegetables simply because it is more efficient than letting cows trample all over the grass..., so why not just get rid of the middle man? I also think the water usage would be way less, not only because cows drink a ton of water, but also because we would need to use waaay less land to generate the same amount of calories... Less land means more natural wildlife and forests which translates to replenishment of underground aquifer... Meat eating is not only normal, but a major part of most cultures, so it is to be expected that we look for reasons that support the continuation of something so dear to our hearts, so this whole "we can only use grazing land for meat" kinda sounds like a convenient excuse to me...