i flew northwest first class ions ago for a red eye and I remember them coming aeround with small (but decent) snacks every couple of hours for the peolpe who stay up. I.e. a salad, antipasto, cookie, ice cream , etc. Same deal with American...

I would call NW and tell them you want to request a meal or that you don't plan to sleep...I'm curious to find out about this too! Good luck.