I have several times. Only thing I trully believe its the hydration part because you are losing water on a fast at first you may need extra... But in the back of my mind I wonder if its the toxins filtering through? I dont know but I hate them.. I just had my 9 one pass this Christmas and it made me soooo sick I was in the hospital. Mine cause infections etc... THEY ARE TRULY HORRIBLE.. Take it from a mother of 3 (natural births.) My heavist baby 9 1/2lbs and kidney stones CAUSE MORE PAIN THAN THAT!!!..
I am embarking on my next fast because i do want to detox and cleans my body and change my eating habits and I dont think they will come back after that.. This is why this time I am going to flood myself with water.. PS when mine was analyzed it was a calcium phosphate which i looked up and it said that the lack of acid in the urine cause some crystals to form to the stone.. So I dont know how well the whole water theory is.. I dont know if this helps but I do feel your pain.. Hope you never have them again.. Good luck..