I was thinking about what type of foods would the Dragon Slayers prefer. I started with wondering, because they aren't actually dragons, and that the dragons themselves are extint and all the slayers had to adapt to human society, if their instincts drive them to look for types of food most similar to their elements, and it all went downhill from there.
Natsu is the easiest, he likes very hot meals, but I feel like he'd be very picky with burnt food, he likes his food well done, NOT burnt.
With Wendy I thought perhaps her stomach is used to digest air faster than liquids so she'd prefer foods with barely any liquid. Her body still requires liquids but she usually takes them at night or at a time where she wouldn't need to be active, since digesting liquids takes longer for her, does that make sense?
Gajeel would definitely need to eat sturdy foods to maintain his teeth' strenght. I thought of Mira discovering this shortly after he joined the guild and, unbeknownst to him, she started using him as a trash can for uneaten scraps that have become dry and hard, not that he's complaining though.
I feel like trying to find the closest thing to eating a lightning bolt, Laxus would go for the spiciest thing he could find, he didn't know why he was obsessed with spicy food for the longest time (Ivan's knowledge about Dragon Slayers was scarce, even more scarce was his feelings of parental duty.) The only person who's come the closest to his spice tolerance is Natsu, but he still couldn't surpass him.
Sting and Rogue were the most hilarious to crack, because What Do You Mean they eat white/black stuff. The only explanation I could conjure was that Sting eats light-colored foods because they reflect more light, and the opposite goes for Rogue of course. On a side note, Rogue could technically simply go to a dark room to eat, he says it brings food more flavor, apparently.
And Erik eats trash, that's it.