You hear it a lot. PETA claims it. Others claim it. The basic claim is that if everybody went vegan, we could feed 10 billion people. However this only takes into account that we are currently feeding a lot of crops to cattle. What it doesn't take into account is that modern agriculture is not in the least sustainable (artificial fertilizers use fossile resources, top soil is slowly depleting etc). So, to phrase this correctly: Does anybody have numbers on how many people we could feed sustainably if humans went vegan? (Disregarding the whole science backing the claim that vegan diet is unhealthy etc, just assuming it were).