What the other two said, also you may want to eat before running or right after, and get some really good protein in you, especially if your a morning runner. The reason way, is you sleep some where between 6 to 8 hours, and say you ate 2 hours before going to bed. that's that's 4 to 5 hours of being flat empty. If you run on top of that, it really makes it hard for your body to come up with enough carbs to burn fat, so then it switches over to protein, then muscle, if it runs out of the carbs to burn fat, and protein. So if your one of those and worry about burning muscle, get some protein and a little bit of carbs before you run. This will give you some fuel to break down and absorb while your running. I have two women right now who run on empty just so they can burn their muscle and not bulk up. Drives me nuts as they won't listen to how bad it is for them, they just too afarid of looking *bulky* and they look like they have no muscle, so I don't get it.
But really do make sure you eat good, as running burns a lot of calories, basically 30% more then walking so if you burn 70 walking distance X, you'll burn 100 running distance X. So that calorie burn adds up really quick, and you need to make sure you are eatting good food but enough calories, not to create a huge calorie defency, a little is good if you want to lose fat, but a big gap, is where you'll lose your muscle.
Kit