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.
This makes calorie burn while walking slightly different from calorie burn while running, which is only distance dependent (i.e. while running it doesn't matter what speed you run a given distance, you will burn the same amount of calories as long as the distance is the same).