These sugars derived from dietary carbohydrate are utilized in three ways . 1- Metabolized to produce energy . Much of the glucose leaves the liver in the blood stream and is conveyed around the body to be used as a fuel for the production of energy for cell activity . 2- Converted to glycogen is synthesized from glucose in the muscles and stored to be released when it is required for the performance of muscular work . Glycogen is also synthesized by and stored in the liver . Liver glycogen is synthesized from glucose , galactose , fructose and the break- down products of protein and fat . 3- Converted to fat . When muscles and liver are stocked with glycogen , excess carbohydrate is converted to fat , which is stored in the adipose tissues .