You could go on the Master Cleanser - otherwise known as the Lemonade Diet. Here is a link to where you can find more info:
http://www.therawfoodsite.com/mastercleanse.htm
I have done this twice, and it works well. I know other people who have done it as well and it worked for them. The first time I did it I lost over 20 lbs by the time it was finished, which takes about 2 weeks in total. You won't likely keep most of that weight off once you go back to a normal diet, but you system will be much cleaner when you are finished.