someone who is on a diet and only eats once a day
individual 1: is that freak sniffing food? what's up with that?
individual 2: they're a food cuck. they sniff food just to feel something
When someone is on the receiving end of ordering a crap meal (worst thing on the menu) and the rest of the table is enjoys their delicious food. All the while they sit and watch a their friends enviously like a cuckold.
Eddie sat and watched while his compatriots enjoyed their beautiful meals. He unfortunately had ordered the blt that the kitchen had not even bothered to put bacon on. In that moment he had been food cucked.
A Food Cuck is a person who finds sexual pleasure in watching other people eat.
This term can also be used as a general insult for someone who doesn't want to get lunch with you.