Fasting... not the best idea.. at all. I know it's been said enough times but people aren't getting the message clearly, and it is horrible for someone to fast for a long time to drop weight and then gain more back. We've lived in the age of plenty for not more than a few hundred years, at best a millenium, but we are a product of millions upon millions of years of evolution, and take it from someone who has studied this, in alot of situations, your body is smarter than you are

.
it is used to living in a time where food can be scarce, and if it recognizes that situation, it starts to conserve energy and the first things to go are your muscles. hell, your experiencing famine, what do you need your muscles for? but fat, fat you need because you store more energy as fat than muscle. so now you start eating again, is your body gonna give you back that muscle? never, its gonna deposit it directly into fat and then wait for more food to deposit into fat.. so this may get people saying "but you see, your body has to use some of that energy to live off of, so its not all going to fat" unfortunately when you starve yourself, your body goes into a mode where you use as little energy as possible, only that essential to survive. What does this mean? you wake up tired, you spend the day tired, your in a depressive state of mind, everything seems harder to do, you have decreased fatigue, you'll notice a major loss in stamina, and these were all once things that used up energy but are now no longer there so the energy that was required for them is no longer needed.. which means you get enough to live off of, and the rest goes directly into fat.
trust me, fasting to lose weight.. BAD idea. I tried it when I was like.. 16, I didn't know any better. I lost 10 lbs, crazy eh! In a month I was 15 pounds heavier lol, trust me it doesn't work. I know more about the body now, i've lost nearly 60 lbs and its a breeze to keep it off, and I don't starve myself either. On the contrary... man do I eat good food
take care, seriously now.. take care.