September 28 2011 2:37 AM
"about eighty percent of all corn grown in the U.S. is consumed by domestic and overseas livestock, poultry, and fish production."
also from that page, 72 million acres are used to grow corn in the us. so 52.6 million acres of land are being used to grow food for our food.
now this part im really just hypothesizing without any solid proof but i think it's plausible- if that land was used to grow food for humans we'd be able to feed about 5x as many people as we currently do with meat. most animals, especially the larger ones like cows, are not an efficient food source.
and i'm really not suggesting everyone go vegetarian immediately, but perhaps in the future we wont have a choice.