Carbohydrate loading maximizes the storage of glycogen in the skeletal muscles. Carbohydrates are the main fuel source of the body and help the overall muscle activities. Carb-loading is used by endurance athletes such as runners, for the purpose of maximizing the storage of glycogen in the skeletal muscles and the liver. However, carbohydrate may cause some discomfort or side effects, such as weight gain, digestive discomfort and also blood sugar changes.