Being vegan will give us much much more farming grounds, so also much much more food. Which may solve world hunger. But also, as we learned in history class, the more food there is, the more money there is, the more time we have to spend on other stuff, everything will develop, also the way we help the poor people and the way they live. In the whole history of mankind, food let us develop, because the climate changed during Medieval Ages we didn't have food and we didn't have development, that's why they call it the dark ages.