Two or three years into my eating disorder, I also began to restrict my water content. If I was restricting my food intake, I would usually be much harsher on the amount of water I would allow myself to drink.  (Meaning that I would only allow myself to drink a certain amount of water a day.) When I had a blood test my doctor told me I was dehaydrated, which was when I realized my restriction of water.  Sometimes I would drink say 3 glasses of water a day, and then go on "water binges" in which I would drink half a gallon of water almost without stopping.
But, I do this no matter if I am binging or restricting. 
I'm thinking it correlates somehow with the need for control, as well as the need to not properly take care of my body.

Has anyone else gone through this?