Depends what you mean by snack. You could bake protein brownies/cookies with low carbs, stevia, whey powder, coconut etc. You could bake your own protein bars. You could carry food around with you (like many do) - boiled eggs, cooked chicken, rice, quinoa, sweet potato, cashews, are some of the things I bring with me daily to work, and they count as snacks/meals. Anything wrong with bringing whey with you and making a shake on the go?