Textbook of Sugar Chemistry

Sugar is a class of edible crystalline substances, mainly sucrose,
lactose, and fructose. Human taste buds interpret its flavor as
sweet. Sugar as a basic food carbohydrate primarily comes from
sugar cane and from sugar beet, but also appears in fruit, honey,
sorghum, sugar maple (in maple syrup), and in many other
sources. It forms the main ingredient in much candy. Excessive
consumption of sugar has been associated with increased
incidences of type 2 diabetes, obesity and tooth decay.