The calories don't count when . . . . .

[DirtDiva]

Of course they fall out. It's all to do with entropy.

Don't forget, of course, that a Diet Coke cancels out whatever calories may have been in whatever you had to eat with it.

[nuthatch]

The calories don't count when you've riden over 20 miles - glycogen stores must be rebuilt!!!

They also don't count when you are at the movies - something about the screen action seems to absorb them.