I had no idea it was actually a word, albeit with nothing to do with PB. Interesting.
Believe it or not, the Heinlein- created word "grok" has more to do with PB than you would think. To grok something is to know and understand something so thoroughly and innately that you become "one with it", in Buddhist parlance. The idea behind PB is to grok your body and its desires and needs in order to help it run optimally and most effciently. The 10 rules mainly point you in the right direction; it is expected that you will edit and experiment and correct your way of life to what matches closest with your needs and desires.
"No fate but what we make"- Sarah Connor, Terminator 2
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, steak in one hand, chocolate in the other, yelling "Holy F***, What a Ride!"
My Primal Battle Tome