I know we defecate or/and urinate to rid ourselves of toxins and excess undigested food. If I was somehow able to get exactly what my body needed to function.

Let's say that I create a pill (or something) that provides the body with literally and exactly the nutrients and hydration it needs, would there still be a reason to carry out excretion?

Do humans or any animal, absolutely have to excrete?


closed as primarily opinion-based by kmm, James, AliceD, fileunderwater, Tyto alba Dec 13 '16 at 4:21

Many good questions generate some degree of opinion based on expert experience, but answers to this question will tend to be almost entirely based on opinions, rather than facts, references, or specific expertise. If this question can be reworded to fit the rules in the help center, please edit the question.

  • 2
    $\begingroup$ I'm not sure I understand the question because it is slightly unclear as it stands. But I think you're asking about a reasonably interesting and answerable topic; how much of our waste is from processing food and drink. A lot of your feces is bacteria, archaea, yeasts, fungi, viruses, and cells from your body. A fully fleshed out answer for this question could be useful, but we need a few edits! $\endgroup$ – James Dec 1 '16 at 3:30
  • $\begingroup$ @James yeah sorry. I have a basic understanding that we pee/poop to remove excess vitamins and toxins, so am just wondering if I have the most perfect diet ever, is there still a need to pee/poop? I'll try and think of how to edit this. I guess most broadly, why do we pee/poop? $\endgroup$ – BruceWayne Dec 1 '16 at 3:45

Yes; there are byproducts of metabolism and maintaining the body that must be excreted, which has nothing to do with taking in unneeded nutrients. For just a few examples, urea is produced normally as part of the constant building and break down of proteins, but must be excreted, the brown color of feces comes from the breakdown of red blood cells, and a substantial weight of the feces is gut bacteria, some of which are necessary for proper digestion of some of the nutrients you take in.

  • $\begingroup$ Hm, that's interesting. So given the fact that I have perfect nutrition thnaks to MiraclePill, would my feces generally be the same amount/weight/etc? You mention substantial weight is due to gut bacteria, so would I expect to poop just as often as now, but just not defecate as much (volume wise)? $\endgroup$ – BruceWayne Dec 5 '16 at 8:38
  • $\begingroup$ "Total parenteral nutrition" is the medical term for full IV feeding - this is not perfected to the "miracle pill" level and typically not used long term, but you can use this to try to find the information you are looking for. I couldn't find an ideal reference for you, in part because patients fed IV are usually quite sick, and in particular they often have serious bowel issues, hence the IV feeding. Just searching around I saw some anecdotes that suggest defecation still occurs but the quantity is reduced - not clear if this is because of frequency or the volume of individual stools. $\endgroup$ – Bryan Krause Dec 5 '16 at 16:15

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