A friend told me about this App.
I was never much for counting calories. Seems a bit unatainable as a pilot type, however My Fitness Pal has just about any airport type foods listed so you can keep track.

Between the calorie counting and exercise follow up I find I can keep things under control and am more apt to work out on layovers and be a bit more careful when considering what I eat on those layovers.

I also carry tuna packs, mainly for when a long day gets out of hand and my food choices at 3am are either that or 5 little bags of pretzels.