This question arose out of a discussion about fasting during Ramadan. Which, if you are not aware, involves abstaining from eating and drinking between dawn and dusk. Something which can be quite difficult in the summer time if you live far away from the equator. Particularly concerning is the effects of dehydration. I am interested in knowing how to ameliorate the effects of not drinking water for as much as 20 hours a day.
It occurs to me that the digestive process itself might consume a significant amount of water and that it might be beneficial if the persons observing the fast not eat very much in the short period of time they are allowed to.
But it's just a wild stab in the dark, I am by no means an expert, so I am looking for refutation or confirmation from an expert. Google searches have yielded nothing with all the results being about whether it's OK to drink water with meals. So here we are.
Just to be clear when I say digestive process I mean the processing of food to extract nutrients in the stomach and intestines, not the subsequent conversion of those nutrients to ATP in the cells (which I understand creates water).
I assume (perhaps wrongly) that the production of bile and stomach acid requires water, some of which will be lost during their interaction with the food and the body won't have a use for everything that enters the bloodstream from the digestive tract and some waste will have to be excreted as urine, causing water loss