Various thivs are defined as an unclear quantity of assorted, unrelated food items that are eaten with the hands in a hideously barbaric fashion.
Separate from eating a meal, which is a formally arranged assortment of ingredients on a plate and is ordinarily done by people with self respect, various thivs are individual ingredients eaten by cavemen who don't give a fuck and can range from tortilla chip crumbs to an entire half of a sandwich.
Essentially, it is snacking until you're not hungry anymore and don't bother eating dinner.
Jackie: Did you eat dinner?
Joe: No I just ate various thivs