If you want to compare what you weight with and without a full intestine
there is a simple process.  The next time you're at the doctors go to
the front desk and ask if they have the directions for how to prepare
for a colonoscopy.  Schedule a night that you only need a couple of
hours of sleep and a day you aren't expected to work and follow the
directions.  It will empty your intestines completely.  As good as any
colonic.  Don't expect the process to be pleasant but it will be very
effective.  Weigh yourself before and after and use the tape measure
before and after.

I recently had a colonoscopy based on my age and the recommended time
for a colonoscopy.  I lost several pounds of crap but under an inch of
belt size, and the pounds and inch were back in several days.
Definitely fat not built up crap.

I think that's a different issue.  Irritable bowel syndrome and Croens
disease are supposed to be caused by grain irritating the intestine and
causing it to leak.  If you have any reason to suspect either of those
try going grain free for a month and see if there is any improvement.

The problem with that approach is folks are often very sick just before
they die so the condition of their body at death can be very different
than what is was most of their life.  Consider Dr Atkins condition
before he fell on the ice (tall, arguably below his ideal weight,
healthy enough to walk to work each morning) and his condition after a
while on life support and intravenous carby feeding.