When do you have to drop this weight by and does your instructor just want you to sweat out water weight or lose fat? I would reccomend, as manofkent has said cleaning up your diet and doing extra excersize to gradually get your weight down. You could probably sweat all of that weight out in a day in water, but DO NOT do it. It's extremely unhealthy and many people have died before. In fact, there are new regulations in my state regaurding weight loss for highschool wrestling because several young men died last year before they could even step on the scale.