Run in the morning

This week I run sometimes in the morning, even before the breakfast. I get the advice of some friends that it's good to run, just once in a while, in the morning, before you eat anything. The reason if something like to teach your muscules to get the energy, not from the normal energy source because you don't have it (you don't eat), but get it from the energy reserves in the fat or muscules. With this training the muscules will improve the way they collect the energy and use it more eficient in the other runs. I'm trying this approach during this week, because I have time.