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.
For high-intensity running, such as interval workouts, the body will rely more on carbs for fuel than fat because they're a quicker source of energy. For long, slower runs, your body starts using fat as an energy source.