this subject of weightloss on a water-only-fast has been discussed many times on this forum in the past, so worthwhile having a look at some of the subject headings in the history.
Weightloss stagnates on a WOF because the body instinctively preserves its food reserves in the ultimate prevention of starvation, whereas a reducing diet will allow the body to burn more calories and therefore result in more weightloss.
Water-fasting per-se has not been considered by many fasting supervisors to be an ideal method of losing weight, if that is the only goal, so you will find that there will be plateaus of little to no weightloss during a fast. One pound per day on average is the norm for most.
If weightloss is your only goal, you are best (in my opinion) to follow a Nutritarian diet, which is essentially one that is low-calorie but nutrient dense. On top of this, if you combine your foods correctly, this will accelerate weightloss, whilst simultaneously allowing yo to eat as much as you like (within reason).
Sounds good to me...........a diet where you can eat with impunity and still lose weight.