I recently watched the video "Forks Over Knives" and my wife and I thought enough of what was said there to buy the book as well. What they advocate is a plant based diet which provides more than enough protein to fuel the human machine without adding potentially damaging elements of the "face-based" (anything with a face) diet. To be sure a vegan diet is difficult to maintain and we are big fans of the Friday night fish fry so we have not become strict vegans. But perfection being the enemy of good enough we have assumed that if we are able to eat a diet that is roughly 85% vegan (I guess that makes us vegetarians?) that we'll derive sufficient benefit to see an improvement in overall health.