Moderation, of course, is key. Like all other oils, olive oil is 100 percent fat. This means it has more than twice as many calories as an equal amount of protein or carbohydrate. The difference among oils is not in their number of calories but in their composition. Among the plant oils, olive, canola and peanut oil are highest in monounsaturated fatty acids.
Olive oil is pressed from the fruit of the olive tree.
Both the type of olive tree and the conditions under which it is grown, such as climate and soil, affect the flavor of the olives produced, and thus the oil pressed from the fruit. Olive oils referred to as virgin are from the first pressing. Extra virgin is also from the first pressing and is the most common type of olive oil sold in the United States. It is a bit higher priced because it offers the widest variety of flavors and is produced in smaller quantities. Extra virgin olive oil is dark green in color and has a rich, fruity taste.