The average human adult has between 8 and 10 pints of blood in their system. Granted that a pint of water weighs approximately 1.25 pounds, and human blood is roughly equivalent in density to water (let's not get into too many decimals here), that means that most adults have between 10 and 13 pounds of blood in their bodies.
When any skinny little tart suggests that they need to lose weight, and they're not having much luck with a diet--or they just need to drop the pounds in a hurry--it occurs to me that they could lose 10 pounds in 10 minutes with a quick unzipping of the forearm.
Beat that, Atkins.
If you're curious, my musings were inspired by these gastronomical athletes:
extreme_diets