Lunch: cheeseburger & fries, or a couple of pizza slices. Later in the afternoon pop-tarts or trail mix, but not lately, it's the over-eating season you know. I probably load up extra carbs, too many, in the evening.

This may sound picky, but you can't really bonk in 10-12 miles. Feeling low on energy may still be influenced by diet but I'd be broadening my investigation to include conditioning, environmental factors, or other possibilities.