someone with a disgustingly unnatural appetite; someone who scarfs down a large amount of food in under a minute
Wow, that kid just ate 4 McDoubles in like 2 minutes. What a food slut.
Someone who dates exclusively for meals and after getting wined and dined to their satisfaction gives the purchaser of their expensive dinners sex.
Bob has taken Diane to dinner at Morton's 5 times this week, and she doesn't even like him. I think she is a food slut.