Sugar is the generalized name for sweet, short-chain, soluble carbohydrates, many of which are used in food. They are composed of carbon, hydrogen, and oxygen. There are various types of sugar derived from different sources. Simple sugars are called monosaccharides and include glucose, fructose, and galactose. Sugars are found in the tissues of most plants, but are present in sufficient concentrations for efficient extraction only in sugarcane and sugar beet. The world produced about 168 million tonnes of sugar in 2011. The average person consumes about 24 kilograms of sugar each year, equivalent to over 260 food calories per person, per day.