Sugar is sweet because it consists almost entirely of sucrose (C12H22O11), which is a solid white disaccharide that alters the flavor of foods. Sucrose is a carbohydrate. Sucrose is broken down in the body into glucose and fructose. When digested, sugar provides approximately 110 calories per ounce (4 calories per gram).
Many processed food products such as Twinkies, children's breakfast cereals, and candy bars contain large amounts of sugar. When consumed in large quantities, sugar is unhealthy, may lead to tooth decay, obesity, or diabetes.
Until the 1990s, it was generally believed that consuming sugary foods caused hyperactivity in children. This notion was never tested scientifically until a study was done in 1999. The study found that sugar consumption was associated with children moving around a lot but was not the cause. For example, kids get excited a lot at birthday parties, where they also eat cake and ice cream. But it's actually the party atmosphere that prompts the extra activity.