Low Calorie, High Volume snacks?

I eat a lot. And I mean A LOT a lot. I work in fast food so I get a lot of processed, unhealthy food for free and I'm realizing how much of a problem it's becoming. I think I just need something to chew on and it doesn't really matter what. Does anyone have any low calorie or healthy snack recommendations that will keep my mouth busy so I don't reach for the bad stuff?