Carbohydrate loading and/or continuous access to glucose are important to provide energy for brain and body function during work in excess of general maintenance of daily life where the requirement will depend on the intensity and duration of work undertaken. Work depletes gradually glycogen stores where glucose needs to be replenished.
Sustained energy release from the digestive tract into the blood stream provides a valuable option to provide this glucose without the ups and downs of blood glucose concentration as a consequence of regular consumption of rapidly digestible forms of glucose - such as in drinks, gels and readily digestible food formats.
Sustained release glucose foods are more convenient to carry than drinks/gels containing sugars (typically soft drinks contain around eleven percent sugar although legislative changes in many jurisdictions with tax implications have reduced this to below five percent where artificial sweeteners may be added for additional sweetness); freeing space for water/electrolyte solutions to be carried as required.