The DNA molecule contains a lot of chemical structures that tell the ribosomes how to create new proteins (that have a lot of functions).
Plus, you can benefit from fat burning even after your run as your body keeps burning fat for 2 to 3 hours after finishing a run. If you want to shed a few pounds, make sure you only ingest liquids and maybe a little protein during that time frame. Training on an empty stomach.
It's not good to eat a meal before you exercise, but its good to have something on your stomach. Usually something high in carbs. I usually do a zone bar or something before I go jogging. I feel better after I'm done...I don't feel so zapped after the run.