Random Unscientific Observations:
The goal of lower-class food is to provide calories as cheaply as possible.
The goal of lower-middle-class food is to taste as good as possible.
The goal of middle-class food is to be healthy and practical.
The goal of upper-middle-class food is to signal one's social and environmental credentials.
The goal of upper-class food is to embarrass any non-upper-class person who tries to eat it.
A couple comments on the last two, because many of my readers have probably never been subjected to upper-middle-class or upper-class food, or they were and didn't know what they were dealing with or why.
Some people really don't care about taste or cost or practicality in their food. They want to keep up appearances by sending the message that they are the 'right kind of person'. So their food will probably be some combination of organic, 'fair trade', and whatever the latest food fashion is. They may think that it is healthy and good for the environment, but it probably isn't.
Upper-class food takes the social games to an even more extreme level. Its goal is to make anyone outside the social circle uncomfortable and/or to make them look bad, thus reinforcing the bonds of the in-crowd. This kind of thing is typical of the upper class. They love to invent arbitrary complicated rules, and make things artificially difficult. Entry into the upper class requires that you spend a lot of time memorizing useless things and developing useless skills. This has been true for millennia. It allows them to feel superior to people who have to spend their time actually earning a living.
Here are some signs that you might be dealing with upper-class food:
1) There are no knives, no forks, and/or no plates.
2) You are expected to eat standing up.
3) The food is either very messy or too big to eat in a single bite. By itself, this is fine, but in combination with points 1 and 2 it is a real killer.
4) There are no trash cans in the room. You have to put everything on a tray that a waiter will carry off.
That's for receptions. At the sit-down meals, they have different ways to mess with you:
1) There are way too many forks and knives and plates.
2) The food requires special unique skills or utensils to eat properly.
3) The place is swarming with way more waiters than is necessary.
And the universal attribute of upper-class food: It is not healthy, good, cheap, or socially responsible. Anything that the lower classes might actually choose to eat on their own is frowned upon, because they might know how to deal with it without looking and feeling bad.
For example, at the conference I attended recently, there was a reception with a 'light refreshments' buffet. One of the things on this buffet was slices of hard toasted white bread, half the size of a slice of normal bread and twice as thick. There were also a lot of sauces and dips that you were presumably supposed to eat with the bread. If you tried to break the bread by hand, you would cover your clothes in a shower of crumbs. If you tried to eat it without breaking it, you would either have to bite through the hard tough bread or stuff the whole thing in your mouth. Both of these would be extremely unpleasant for both you and anyone who saw you.
I have no idea how we were supposed to eat this bread. Maybe finishing schools teach you how to break bread without causing crumbs or getting your hands dirty. Maybe you weren't even supposed to try. It could simply have been a a trap for the unwary. I stayed with the fruit. Even though the pineapple chunks were far bigger than was proper or comfortable, I was able to eat them in a single bite without any unpleasantness.