The most suffering we can stop

There are 7 billion people in the world. Even counting only birds and mammals, there are more than 10 times this many animals slaughtered to feed humans every single year. And this slaughtering continues not due to anyone having decided it's worthwhile for our nutritional needs, but due nearly completely to humans turning a blind eye to the suffering, and to the fact that so much suffering has been wrought only to please our palates. All of our nutritional needs can be provided, and more, without this, by switching to vegetarian or vegan diets.