Beef may often be "what's for dinner" throughout many parts of the world, but there's no doubt the habit comes at a heavy price. In addition to taking the lives of 16 billion or so animals each year in the United States alone -- yes, that's billion -- meat takes a significant toll on the environment. Roughly 16 pounds of grain and 2,400 gallons of water are required to produce just a single pound of meat, according to PETA. That pound might also account for the clearing of some 55 square feet of rainforest for grazing cattle.