Earlier quoted context omitted.
A beer is, say, 150 calories. A mile of running burns about 100 calories. When I ran, cruising speed was 7 minutes per mile. So a light 6 mile (10k) run would be about 45 minutes, 600 calories, or 6 miles.
And that doesn't even take into account the increased metabolism after the run is finished, nor the increased resting burn rate (over time) due to increased muscle mass.
One of the marathons I ran had a "carbo-loading" event. Basically huge vats of spaghetti were cooked, and runners would absolutely gorge. It's totally unnecessary, IMHO. It's good to eat enough and cleanly before a big run, but stuffing yourself just weighs you down. And come mile 20 or so, you're not going to be worried about how much energy you have to burn, but rather how much everything hurts.