well my poop must be made of bricks then lol
one of my fave past times a couple years ago was doing before and after weigh ins for poop times (and pees, showers, eating a large meal, menstual cycles, workouts, etc, but i digress lol)
...and in the case of pooping, i almost always weigh less after. mind u i only poop every 3 days or so (a post-wls phenomenon for me), so i get pretty backed up.
there have been a couple/few times i went on vacay (or had surgery) and didn't poop for like 10+ days and when i finally did i would drop up to 2.5 lbs. *shudder*