I used to lose on average 2 pounds per day while fasting for 14 days. Got nice and skinny, then put it all back on over 3 months. The weight loss is not the same each day and continues for a few after the fast.
My opinion is that fasting would be the fastest and best way to lose weight, even if you do put it back on again. Minimum should be 14 days because if you fast for short bursts too often it could become like anorexia.
My feeling is that you learn from fasting and gradually alter your eating habits as you realise that bad food is not the best for you.
It is critical that you end your fasts slowly. I like to begin about 6pm with a tablespoon of orange juice, a full orange squeezed about 7 or 8pm, small slice of other fruit 9pm and go to bed.
I start in the early evening to stop myself from binge eating before my body has fully kicked in to dissolving food again. That should happen slowly overnight while I sleep.
The next morning I might begin with two small slices of some fruit chewing a lot to make it very well dissolved and follow every 2 hrs with a little bigger portion each time of various foods, mainly easily digested foods that I chew very well. I might even have a full meal that night except it would be about a quarter of my pre fast size.
After that it is up to you to resist improper foods. What I have found is that natural foods taste delicious until you have something processed like a sauce. The flavours in processed foods suddenly make you dissatisfied with natural foods and you want to eat some junk again.
If you put on too much weight try fasting like that again each 6 months and you will slowly change your habits.