yeah...there's a big difference in class AND the time of the flight... if you are even 30 minutes off from the 'offical meal' time
you won't even get a snack on coach class most of the time.
i remember when i was on the coach (reno-washington) class, for lunch, i got a ham bagel sandwich w/ coleslaw and a cup fo cheap fruit salad. however, on a first class 777 on the way back (was stand-by for business class, but it filled up, they ask me if i want first class instead with no extra charge, as if i'm going to turn it down), for lunch, i got a couple glasses of wine to start, pasta salad, grilled chicken sandwich, fruit bowl(with more fancier exotic fruits), and chocolate cheesecake.
looking at the price, it is not worth it ...for example, Richmond to Taiwan round trip coach can run about $800, while business class is $3000 easy. i think it might be cheaper to 'upgrade' once you get to airport. or bring your own 'first class' cooking.