My favorite paragraph from Robb Wolf's book:
Plant sources of protein, even when combined to provide all the essential amino acids, are far too heavy in carbohydrate, irritate the gut, and steal vitamins and minerals from the body via anti-nutrients. Remember that whole chapter on the double-edged nature of grains and legumes? Beans and rice, nuts and seeds, are what I call "Third World proteins." They will keep you alive, but they will not allow you to thrive. Your protein needs to have the following criteria:
1. It needs a face.
2. It needs a soul.
3. You need to kill it, and bring its essence into your being.