Losing weight during a fast has many different parts. First off if you are overweight, your fat breaking into water and oxygen. If you are adding a hold load of water on top of that your body isn't going to get rid of that water. That is why it is ALWAYS recommended to only drink to thirst. On every one of my fasts I may consume an 8 oz cup of water daily, and the longer the fast the less water I drink. Ones body doesn't need all that water.
Secondly ... if your diet consisted of processed and salty foods then your body is going to take time to adjust to the lack of those nutrients in those foods. It took years for your body to adapt to the toxic levels of junk you fed it ... it is going to take several long extended fasts to reset the system.
Often overweight persons come to this board thinking a fast is their miracle. Wrong ... fasting is only going to reset the system. Overweight people have many many things that are off in their bodies. A body must work hard to reset all the components that were damaged by a toxic and often calorie heavy diet. Having the assumption your weight will just fall off is the wrong approach. Instead you should be thinking about which part of your body it is going to correct first. I have got news for you ... it isn't going to be what you think it should be.
Simply sit back and relax. Understand your body is going to do what it wants to do ... if it holds onto weight, well then there is a reason. If it drops the weight, well then there is a reason as well.
The best thing you can do are several 14-28 Water Fasts over a 9-18 month period. In between the fasts eat a mostly vegetable and fruit diet.