According to a 2009 poll, around 1% of American adults reported eating no animal products. In 2011 that number rose to 2.5%--more than double, but still dwarfed by the 48% who reported eating meat, fish or poultry at all of their meals. In this country, most of us are blessed with an abundance of food and food choices. So taking into account our health, the environment and ethical concerns, which diet is best? Are we or aren't we meant to be carnivores?