I never eat on board aircraft, just because I am a fussy eater and tend to eat a light meal before I board and on 12+ hour flights will take a snack to munch if I get hungry.
I normally fly business class, and during night flights the crew tend to be absolutely fine when you don't take a meal. But the confusion during day time flights, particularly with any of the Asian airlines can be ridiculous. I have had the Cabin Manager/Purser/CSD come up to me to find out if there is something wrong, do I have a problem with the menu or am I sick. It seems to be beyond comprehension at times that I am just not hungry and a black coffee with perhaps a biscuit will suffice.