I agree with the comment above. I had an eating disorder for years. You will only keep the weight on because your body is in starvation mode. It's going to do anything it can to keep the weight and fat so it doesn't die.
Trust me. Once I started eating normally but healthy foods, I actually lost weight. Now I pretty much eat all day but healthy foods and I am in good shape.
STOP doing this right now. I wrecked my body. It was to a point that I was eating a quarter of a bagel the entire day. My immune system is shot as well as my digestive system. Please take my advice.
You are starving yourself. Anything under 900 calories a day will put your body into starvation mode. Even if you do lose weight it will be difficult to keep off if you start eating normally because your body will try to store every bit of excess energy it can get in case you starve it again. Not to mention all the health problems starvation can cause. If you find you are having difficulty/feeling guilty about consuming at least 900 calories a day (and thats net calories, ie. If you burn 300 calories exercising you should be eating at least 1200) I would advise a visit to the doctor before it gets out of hand. This could be the beginning of an eating disorder.