Fasting tomorrow

Starting another fast tomorrow.

Not sure why is it, that my first and second Water Fast long time back, I lose about 4 to 6 pounds on the first day, second about 3 or 2 pounds, and then on about 2 pounds until first week, (i wasn't in heavy weight), but now it seems I can't loose the same amount of weight.

I am loosing approximately 2 or 3 pounds on the first and second day, at the end I don't loose that much like in my first and second, what am I doing wrong ? or is it the body, may be used to fasting ?