Any class is bad when you're sick. I know my parents got sick on a few TPAC due to spoiled food. When I picked them up during those times, they were always dehydrated and extremely tired.

If I could reheat the dim sum, then definitely yes. I mean it won't kill you eating it cold, but the vast majority of dim sum I can think of needs to be served hot to taste decent (and in some cases to even be edible). Sashimi and sushi would also be out of the question (unless they were something like veggie rolls). I would be interested in trying something like an ekiben, but I've been told the self heating packs/FRHs are illegal (I can understand that) so that's out of the question.

Sandwiches are a mixed bag as well. Haven't tried bahn mi, Most other sandwiches/burgers tend to turn out dried and hard after an hour or two up in the air.

About the only "fresh" things I can think of right now are things like char-siu or roast pork (or charcuterie board things) or maybe some cheese/fruits or salad (and pray the security check staff aren't going to confiscate your salad dressing).. Snacks are good too, but trying to eat healthier these days is always a good idea.

I will say this. Next AC flight I take, I'm bringing some of those Nong Shim ramen cups... If for nothing else, just the entertainment value of watching other passengers tell the cabin crew they want what I'm having instead of the generic chicken noodles is worth it. If I get out of Singapore/Taiwan/Japan, some of those Nissin cups will suffice as well.