Actually I think you burn it because you use up carbohydrates while you exercise or when you just move and once those run out you use lipids (aka fat) and those start to burn away as well to give you energy.
Doctor Who explains science <<< He looks like he trying to understand rocket science in that second one.<<<Why can't science books explain things this way? They need a section for "Science Explained by The Doctor"
I cried so much in that moment. I actually began to wonder if 10 really was My Doctor, or could 12 slowly be stealing my heart? ♥ That was the moment.the moment we realized Twelve does in fact have not one, but TWO hearts.