[neilep (OP)]

In the course of digestion and foody travelling through twenty thousand miles of intestine, does the weight of the food/substance remain the same until i poop it out ?


whajafink ?

[paul cotter]

In a word, no. As food transits the digestive system a large volume of digestive juices and bile are added to the grass you have eaten. Also as nutrients are absorbed bacterial growth on the remnants increases the mass that is in transit and the amount of fluid left in the droppings depends on how long they have resided in the colon. Ovine digestion is a bit more complicated that of humans as cellulose in the grass you eat has to be broken down but the principles are the same.

[Bored chemist]

It's a matter of definition. If you stand on the bathroom scales the answer will be nearly* "yes".
If we find a way to discount the mass of your stomach contents from the mass of "you" then no.

*
Not quite constant, because you lose mass by breathing.
You lose water and the CO2 you exhale is heavier than the O2 which you took in.

[Karen W.]

So are you saying it takes on more weight as it stays or that there is fluid loss excreted from urine and breathing etc.. but that overall it gains mass??? I'm kinda confused?

[alancalverd]

Since everything you eat or drink goes down much the same pathway until it is digested, you can say simplistically that the stomach initially contains the mass of your last meal, and the total of what is excreted by the various pathways has a larger mass (for an adult) due to the addition of oxygen in its combustion, but possibly a smaller mass in the case of a child as some of the intake will be stored as new bone, fat, muscle etc  (you are what you eat).

Since a considerable proportion of our intake is water, the mass of feces will on average be less than the mass of "solid" food intake as much of the water content has been extracted by the colon, cycled through the kidneys, and mostly excreted as urine.

[Karen W.]

Ok, so a tad less...