ok i started taking my friend to the gym to keep each other motivated, and he bet me $10 i couldnt' burn 1000cals in 2 hours on a bike, well at 43min i got to 600, and boosted the level setting to max, and burnt the other 400ish in 25min, now. considering i took in about.. 800ish that day, is that unhealthy (btw no i didn't feel dizzy or weird after, it didn't FEEL unhealthy) but i dunno if thats a good thing to do lol, dont know how loseing weight could be BAD but then again im not a doctor, what do i know =D

burning that many calories isn't, but only eating 800 definately is unhealthy. You can survive doing that once in awhile, but forget about using straight numbers like that to reach a weight-loss goal. When using the simple subtraction method of calories, you have to remember that you burn a lot of calories throughout the day. And, the less you eat, the slower your metabolism gets to try and conserve energy ... it's a self-defeating process.