Flat assertions of efficacy unadorned by empirical support may not be well received. However, I am sure that the idea is taken seriously by most, and that supporting evidence would be of great interest.
I used to back it up by quite a bit of data but I get downvoted to oblivion regardless of all the effort. Why bother anymore. I put it here, whoever is interested can research on their own.
Meaning restricting water intake? Or general fasting with only water consumed?
Usually general fasting with only water consumed. Many practitioners will allow unadulterated coffee or tea. I haven't seen much evidence to indicate that dry fasting provides additional health benefits over water fasting.