Olives are a great choice for a low-calorie snack or recipe ingredient. They add flavor and variety with only 5 calories per large olive (25 calories per serving). Most folks think olives have more calories than other foods. Recent research reveals that many consumers think black ripe olives have more than five times the number of calories than they actually have. The truth is olives are a great, low-calorie food. This just goes to show that not everything that tastes good has too many calories.