You cannot lose 5 pounds in one day. It takes a defecit of 3500 calories to lose one pound. You would need to do some pretty intense cardio for almost 6 hours to burn that. (1 hour of vigorous cardio=600 calories burned). To burn 5 pounds, that's 17500 calories, or a little over 29 hours of cardio. So, sorry, but it's just not physically possible, even if you were to exercise for all 24 hours in the day.