How do you lose 5 lbs in 5 days?
In order to lose 5 pounds in 5 days, you would need to lose 1 pound per day. You would need to burn 3,500 calories each day.
It's not possible to lose 50 lbs. in 10 days. The safe rate of weight loss, according to doctors, is 1.5 lbs. per week. To try to lose more weight than that would be very difficult and definitely dangerous for health. I'm sorry to disappoint you but it's not possible. You cannot lose 50 pounds of body fat in 10 days by any natural means.
It is improbable to 18 lbs in 4 days, but not impossible. The question is, is it safe. If you were to even lose 18 lbs in 4 days it would have to be all water weight, you could not lose that much fat in the shirt amount of time. Here is a website that you may use as a guideline for quick water weight loss. http://www.everydiet.org/diet/3-day-diet