How can you lose 20 pounds in 20 days?

Its impossible to lose 20 pounds of fat in 20 days, but it is possible to lose 20 pounds in 20 days- with much of it being water weight though.
Some sort of detox would be your best bet: lots of water, fruits and veg.
Btw dont bother with harsh laxatives, they may appear to help with the 20 pounds but infact they make you retain water more after a few days and can mess up your digestive system... so stick with natural stuff that the body can deal with more healthily and easily

Or you could lose 20 pounds of money :P