I'm training for my first half-marathon (1 month to go), and I've definitely fallen into the weight gain issue that many articles discuss (see below). It's just really hard not to over-eat after a long run. You need to eat more the day of, but I've been ravenous the day after, which is usually a rest day where you don't burn many calories at all! And, the added weight just makes running harder, of course.
The only thing to do is double-down on logging. It's easy to get sloppy when you have 1000+ "exercise calories" to eat.
Anyone else working this problem?