Much like "sick" or "ill" unhealthy is the newest word used to express awe or approval of something. It can be applied to any noun but is often used in a sequence.
1. Dude that trick was unhealthy
2. Yo, this samwhich is mad ill unhealthy sick nasty
The opposite of health food. You go to a "green" market for health food, and you go to a burger joint for food that is guaranteed to raise your cholesterol level to the top of the Empire State Building and load you up with a week's worth of sodium.
Losing something with no hope of every regaining possesion of it. Having something "stolen" from you by "the world". This is different from something that you have missplaced, or simply don't know where it is at the moment in that this item was lostforever.
I want to get an iPod, but I'm sure I'll unsteal it.