What is a complex carbohydrate?

Carbohydrates serve as fuel and building material.. They include both sugars and polymers of sugars. The simplest are the monosaccharides or single sugars, also known as simple sugars. Disaccharides are double sugars consisting of two monosaccharides joined by condensation reaction. Polysaccharides are carbohydrates which are made up of many monosaccharides condensed together; they are also called Complex Carbohydrates.