Here are some questions often asked of vegans (Hey! Wait a second! I'm a vegan!!) After reading the wise, mature, measured responses of thirty-five year vegan Butterflies Katz, the well respected blogger of Veganism: A Truth Whose Time Has Come, this is how I would answer the same questions.
Humans need animal products for survival. You will die earlier. There are things in meat, which your body needs and you cannot get from any other kind of food.