I am fasting on water {a little green tea {Black} } for 15 days and I am hoping to lose 20 lbs. I want to know if it's possible. I weight 133lbs right now and I have a high metabolism, I am about 5'5'' maybe 5'6''. Is it possible? I want to be about 115 for the holidays which, for me, start the 17th of Dec.