Whether you’re eating them whole as a snack or chopping them to top a salad or pizza, black olives add a bit of extra nutrition to your diet. The tiny fruit , olives are considered a fruit because they contain a seed and develop from a flower is rich in monounsaturated fat, fiber, beta carotene and vitamin E. However, as a high-fat fruit, black olives are a concentrated source of calories, and they're also high in sodium, so enjoy them in moderation.