I started an 'exercise' on my fitbit right before my last onsight started. Fitbit claimed that I burned ~6K calories that day. My 3 week running average is somewhere around 4K.
Im a recovering chunk monster. Im down 80lbs in 6 months and now I've got pretty decent cardio (6 miles in an hour on the treadmill 5 times a week), but still weigh 250lbs. If you're fat but move a lot you can burn some massive calories, or at least my fitbit says so.
