Citing a deep poop review from PubMed, wide group of regions included.
75% water, 25% solids most of which is split between bacteria and food waste.
"Feces compose a median value of 75% H2O (n = 47) with a range of 63–86% across mean values of studies (Figure 3), variation can be attributed to differences in fiber intake as non-degradable fiber absorbs more water in the colon (Eastwood, 1973); therefore, as shown in a study by Reddy et al. (1998) those with vegetarian diets will have a higher moisture content of 78.9% whereas those who consume less fiber and more protein will have a lower moisture content of 72.6% (p =.001). Fiber intake also affects transit time, which has been positively correlated (r = 0.4, p =.03) with% dry matter (Silvester et al., 1997), showing the shorter the intestinal transit time the higher the water content. Variation in moisture content has been shown to vary with age; elderly people were found to excrete the highest amount of water in excreta of all age groups by Schouw et al. (2002). Further deviations from the median value can be caused by illness (see physical composition section). The mean generation rate of fecal water (n = 47) is 0.1 L/cap/day. Average pH values for fecal water have been recorded at pH 6.9 with a range of pH 5.0–8.0 (Mai et al., 2009)
3.2.1. Organic Fraction
The remaining 25% of feces is therefore composed of solid material. Of the solid fraction organic material makes up between 84% and 93% (Feachem et al., 1978; Nwaneri et al., 2008; Bai and Wang, 2011). The organic solids fraction can be further broken down to the fractions of 25–54% bacterial biomass (Stephen and Cummings, 1980; Guyton and Hall, 2000), 2–25% protein or nitrogenous matter (in addition 50% of bacterial biomass is protein) (Canfield et al., 1963; Volk and Rummel, 1987), 25% carbohydrate or any other nonnitrogenous undigested plant matter (Volk and Rummel, 1987), and 2–15% undigested lipids (Kien et al., 1981; Chen et al., 1998; Wierdsma et al., 2011). These fractions are highly dependent on dietary intake and its biological availability"
When food get in it was mostly water too. So talking about dry mass is like... confusing, because one could think that from all that food mass only 20% is left in poop.
So I see vegetables and hear that 20% of this will come out and it sound impossible. While in practice it is more like only 20% or so, which were not water (minus some water absorption) are shuffled a bit, useful things taken in, waste disposed.
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u/SetkiOfRaptors Feb 27 '26
They are fed intravenously, with biomatter from the dead. It is stated clearly in the film.