More than 15 years ago, when I became a vegetarian, it was for "humane" reasons. Then in college when my cholesterol shot through the roof after I spent six months living in Italy, I chose vegetarianism for health reasons. Recently, I haven't really known why I stay away from meat. Sometimes I think it's to narrow my options. But tonight, after a brilliant and tasty vegan dinner cooked up by Art Eggertsen, activist and founder of ProBar, I'm thinking that maybe my newest raison d'etre is not just the humanity (nothing against meat eaters!), it's the sustainability of eating a plant-based diet. Did you know that food production accounts for more greenhouse gas emissions than transporting that same food? Pretty provocative. So. Why are you a vegetarian or vegan?