That is, if I ate and excreted normally (if anyone is going to ask me to define my terms, I will admit upfront that I have no idea what the average person’s poop schedule is), how “full” would my intestines be at any given time? Also, how much would the contents weigh?
There’s no “normal” when it comes to humans, just a large range that is considered to be healthy. Doctors consider anywhere from three bowel movements a day to three a week to be normal.
And there is also no normal for a digestive system. You can find a variety of figures for how long it takes food to go all the way from the mouth to the colon. The average figure is somewhere around ten hours, although it can be much shorter or much longer.
At ten hours, though, it’s pretty sure that there will always be something in the system. How much is entirely dependent on how much is being put in. However, you have to remember that the entire purpose of the intestines is to remove all possible nutrients from food. And water as well. A high percentage of the weight in almost all foods is water weight and the intestines absorb the water from food extremely effectively. Therefore the weight of the internal contents (known as chyme) will be reduced considerably from whatever you take in. It’s at its highest about an hour after a large meal and at its lowest after a fast. I don’t know how to quantify it beyond that.
It’s also important to remember that a large part of the intestinal contents is not food, but dead cells and bacteria on their way to becoming feces.
While we’re on this subject, I was wondering about intestinal length – I read in a work of fiction that the intestines become longer in those who eat heavily for a long time. Is this true, or did the writer make itup?
I think he’s asking, “How many pounds of shit do we carry around with us?” 
I’ve always thought those backpacking dudes who carry ultra-light A-frames and 3 ounce sleeping bags get secretly thrilled every time they shit so they can be a few pounds lighter. But people vary way too much (and the SAME person varies a lot with time, disease load, diet, metabolism, activity, access to facilities, water content of feces, etc.) to meaningfully estimate the Chairman’s Pow – ounces to pounds. Not that I’d want to.
Well, that was *one * part of the question.
But, the [first] question, as far as I can see it, is answered. Thanks for the info.
Three times in one day after thanksgiving sure, but three times a day, everyday?
Why Not?
If you (or he) keeps on stuffing it in, it has to be retained or push some out!
Three a day could be normal if they’re small; a healthy person probably isn’t having three giant ones a day. In another thread (I can’t recall which) someone posited that perhaps this is more common in women - they’re already sitting down to urinate, so if they find that there’s a bit in there, they’ll have a small bowel movement while they’re already there. Since men generally have to make a specific decision to sit down and have a bowel movement, they tend to have larger ones less often.
I have a friend who’s a geriatrician, and one day over lunch (I regularly went out on Thursdays with him and my father), he was discussing the usefulness of a quick-and-dirty way of figuring out how much an older person’s weight would fluctuate based on constipation.
After making the assumption, based on the premise that “Sometimes it sinks and sometimes it floats,” that feces can be assumed to weigh roughly the same as water, he did some math based on the length and diameter of the average intestine. I’m not doing it justice here, because it was truly very interesting to watch him figure it out on a placemat.
Allowing for some fudging [HA!] of the numbers, he came to the conclusion that at the upper end of the scale, it’s possible that a badly-constipated person may have up to 10 kilos of feces in them.
Holy crap. I vaguely recall a SD article on this (or at least John Wayne).
Geeze…I’m sure glad I wasn’t at the next table and within earshot of THAT conversation…