I’d say not, Bunny - if we take the non-water fluids and put them with the rest of stuff in the body that’s not water, then all that remains - a given amount - will be water, no?
I’m still not sure about the advisability of dry-fasting, but definitely no drinking when doing it. Not sure of the harm of denying water to the body early on, i.e. when first thirst presents itself. Unless there are known issues, there could be benefits - improved kidney function and maybe improved blood circulation within the kidneys, as mentioned in that study?
Even just among the people on this forum, there’s a wide range of how much water is consumed, on average. Unless there is a medical reason like kidney stones, dark urine, etc., I see no rational need to drink when we’re not thirsty. There does seem to be a substantial amount of advice given to drink more than that - to start drinking before one gets thirsty.
My own anecdotal experience is that on many days I’ll just have a cup or two of black coffee, and that may be all the water I take in, especially if not eating.
The flipside was a day a couple weeks ago, working moderately hard in a slightly hot environment, and perspiring somewhat. Not much, a very small fraction of what maximum perspiration is. I got thirsty fast and drank 2 liters of water in an hour.