Do cardio in the fat-burning zone (60-70% VO2 max) to lose the most fat!
Cardio is useless for fat loss unless you do it on an empty system, like first thing in the morning before you eat!
If you run too hard, you're burning muscle!
......aaarrggghhhh RYDAIN SMASH!!!!!
Back in the real world where real scientists collect and observe real data, we've learned that consuming fat as a substrate during exercise does not translate into increased bodyfat loss. Actually, the opposite seems to be the case. The 1994 Tremblay study demonstrated that high-intensity interval training (HIIT), in which trainees alternate short anaerobic work intervals with longer, lower-intensity recovery intervals, induces fat loss up to nine times more efficiently than endurance cardio although the HIIT trainees' cardio used mainly glycogen (stored sugar) as fuel and didn't even burn as many calories as the endurance program overall. I don't know all the reasons for this, but a simplified explanation is that HIIT causes your body to consume fat as it recovers from the exercise.
The empty system myth is just silly. Essentially, they're claiming that cardio doesn't "work" if you eat first because you're "burning off what you just ate". As I mentioned above, some cardio does its best fat-loss-related work when you're done exercising, so there's no point in worrying about what you're burning off. Even if you don't do HIIT, as long as you consume fewer calories than you expend, you're going to lose fat. Your body needs those missing calories to help it operate, and it can't exactly create them out of thin air. Claiming otherwise is tantamount to saying that you can take as much money out of your checking account as you want to as long as you do so after you deposited your paycheck. Unfortunately, money doesn't seem to work that way. Who'da thunk it?
In fact, if you're doing HIIT, you must eat first so you have enough glycogen to fuel the exercise. Myth #3 is actually more of a misconception because it can indeed be true if your glycogen stores are low, forcing your body to break down muscle in order to generate fuel for your workout. (The reason I put it on the myth list is that I generally seen it treated as gospel - i.e. if you work out too hard, you'll automagically start gobbling up that precious muscle tissue.)
(Hrm...this is actual content! Methinks me shall edit it and post it on Meow Mix later...)