What is a good, healthy, tasty snack to eat between lunch and dinner?

I usually eat lunch at noon and dinner at 7. I find myself getting really hungry in the office around 4:00. What would be a yummy tasty snack that I could bring from home, that would be filling enough to get me through till dinner? I’m looking for something that’s not packaged (i.e. no power bars) and doesn’t have any added sugar.