Sugar is a type of nutrient which belongs to the class of food called carbohydrates. There are three major classes of sugar namely Monosaccharides (e.g. glucose), Oligosaccharides (e.g. sucrose and fructose) and Polysaccharides (e.g. starch). Many sugars exist such as sucrose (in sugar cane), lactose (in milk) and maltose (in cereals).