Do not do it, you need to lose the weight at the same rate you put it on, or you will have an endless battle with the weight issue. I would not recommend shifting weight at rapid speeds unless it is for surgery. I know it's one of those things you want to see the results instantly but, if you lose it slower, when you get to your ideal weight, you will be much happier. Lose it too fast, get to your desired weight and stop and you will put weight on faster than ever and you will more than likely weigh more than before.
Eating so little calories a day is so bad for your body, not only are you not getting enough nutrients but it will slow your metabolism down - so again, when you get back onto real food again, your weight will shoot up again.
A balanced diet and a bit of exercise works wonders, it will take longer but it will be so much easier in the long run. You will feel so much better for it too. I hated my weight, I have changed my diet to healthy eating and have one naughty day a week, you appreciate the naughty foods a whole lot more too. Ok I do a lot of exercise too but that just makes me feel so much better, three stone so far, one more to go.