>>4305312um...this isn't healthy and it really depends on how much you need to lose but here is an option for you.
It's an old Military diet called the Grapefruit diet. You are not allowed to eat anything but 1 grapefruit for each meal of the day and then 4oz of bacon in the morning. Of course you need to avoid soda and no sugar on your grapefruit.
If you do this it will suck. You will feel sick and you will literally shit grapefruit. But it's effective and fast, albeit horribly unhealthy.