Whether you walk it or run it, a mile is about 100 calories. So, give or take, ~20,000 calories. Divide by 3500 calories/lb. and he burned five pounds of fat he probably didn't have to spare. But not so fast, he was also consuming calories along the way, and consuming a lot.

So calculating the net burn would be quite difficult. But the gross burn was probably about five pounds/2.25Kg.

I don't know about that, it's probably not super precise but an hour running is 600-700 kcal burned, reported by Garmin Connect