vx
I'd read a book on fasting. There are much more compelling reasons to fast than "losing X pounds" imo. It will give additional inspiration for doing it the fast to completion and doing it correctly.
If this is your first fast, day 2 and 3 it will be brutal. By brutal, I mean you'll be detoxing and you will likely need complete bed rest. You might not need it, but it's better to be safe than sorry.
Usually people lose 1 pound per day when fasting and gain up to 3-5
pounds back after it's over.