Low-calorie snacks?

I’m currently trying to lose weight and have been struggling with a constant urge to snack. Instead of fighting a losing battle, I want to find very low-calorie snack options that won't derail my progress.

The problem is that I’m a very picky eater. For instance, I find it extremely difficult to eat anything green. It’s not the taste—the color itself makes me feel nauseous.

If you have any tips or ideas, I’m open to suggestions.