I never did lose the 10 pounds I wanted to before the Whidbey half marathon. Now, ironically, I have an additional 3-5 pounds to shed, thanks to the carb loading and so forth that accompanied my month of races (Tulip, Whidbey, Robie Creek, Bloomsday).
But at least I can congratulate myself that I am not a gaunt-faced runner! One of my favorite running bloggers, Nitmos, has written a great piece about runners who are too skinny. I totally know what he means. I call these guys (although there are plenty of women too) "Skeletor." This look is especially popular in runners in their forties and up, I think because your face becomes more angular as you age, and if you are excessively thin, it really shows in your face. (I have really appreciated growing cheekbones in my mature years, but still have plenty of fat padding as well.)
Of course you especially notice this extreme thinness amongst elite runners, if you are ever in a position to see them. I think I have only seen true elites on TV and film. Deena Kastor in The Spirit of the Marathon is a fascinating example of this. In her narrative bits, which were presumable filmed when she wasn't training for a major race, her face is attractively normal, even a bit round, perhaps. In contrast, during the Chicago marathon segments, she is much thinner and hollower, appearing, by the end of the marathon, to be but a shadow of her former self. (And she claims to eat about 5000 calories a day when training for a marathon!)
Obviously the top runners are different from you and me. Well, me, anyway. Even if I ran a marathon, technically that would burn off 2600-3000 calories, not even a pound's worth of fat. I could make that up in cinnamon rolls, easy!
You won't be calling me Skeletor any time soon.