What its the best way for a 21 year old female to loose a drastic amount off weight? at lest 80 pounds, in the fastest amount of time.

Avoid drastic measur: You don't need drastic measure, as they won't help. You need to learn how to eat and exercise properly for the rest of your life, otherwise you're shorten it unnecessarily. You have to burn off 3500 calories you don't take in just to lose one pound. 80x3500= 280, 000 calories. That's the equivalent of walking across the United States 93 times. Good luck!