One time I found a decent place serving tasty food to taxi drivers at Toronto's airport (a short walk outside to where the limo drivers park). They're mostly South Asian, so the place had good basic oily "sweets shops" type Indian fare like thali, nan and so on. Of course once you go through security you lose that option.
Similarly, years ago, when I frequented Taipei's airport I found a "secret" cafeteria that served up excellent basic Chinese food to the workers at a fraction of a price of the big (usually empty) restaurants.
To find that kind of venue, you'd have to ask someone (they might not tell you) or do some in-depth research of the particular airport.
Not sure if either is still there, both were more than 10 years ago. I don't eat that much these days, and if I do anything I usually just bring a few security-compatible snacks in my carry-on. Gorp, chips (crisps), fresh or dried fruit, jerky, that sort of thing. Sometimes apples, instant oatmeal and powdered 3-in-1 coffee for arrival so I don't have to go searching when I get there. If it's an international flight with customs at the destination you can consume anything in-flight that might cause them to raise their eyebrows (especially meats). Most of the flights I take these days have edible meals so I don't need to worry about being hungry after the doors close.
Many airports these days have food from well-known chains (albeit at higher prices, usually) so it's not so much an unknown as it once was. Not so much better, but predictable. I'd rather plan out a place once I arrive (if the time is suitable), rarely is anything at an airport very memorable.