Will I lose 15 pounds in a month from doing this ?

This sounds very unhealthy! Your only suppose to loose 2 lbs a week or 10 lbs a month. You could be damaging your organs with a diet like this. I think you should do it the right way and stay health and don't worry so much about loosing weight so you can look good in a swim suit. Your life is more important then loosing 15 lbs.