It really depends on your current diet. If you drink everything but water, make the switch to nothing but water.....that can take you there by itself....increasing your fiber intake naturally or with psyllium husks is also something to try, as well as taking 2 doses of stacker or something similar every day until the meet....(you can take one day off a week to keep your tolerance low)
It's only 8 lbs man, no need to get crazy.