No fat burning until 20 minutes?
You hear this said a lot that you have to do cardio for 20 minutes before your body starts burning fat. Ignoring the fact that calories burnt is more important than fat burnt during cardio this doesn't make sense to me
At low intensity activity (like just living or walking around) your body is burning primarily fat. So if you get on a piece of cardio equipment and workout at a low intensity your body will be burning fat right from the start.
With high intensity cardio or HIIT your body will burn primarily carbs due to the greater energy requirement and the fact that the body cannot metabolise fat fast enough. And if I'm doing high intensity then it is either for the CV benefits or the EPOC effect anyway.
So isn't this a pointless rule?