I am trying to imagine another 200-300 lbs on my body and it scare the shit out of me. Carrying 2 boxes of cat litter it hard on you from the shop to the house. Imagine 5 times that much EVERY DAY!!! Blarg blarg blarggg TEN BOXES OF CAT LITTER. ON YOUR BODY. ALL THE TIME.  edit: I am now measuring weight in cat littler. Only slightly more logical than stone.