Carbohydrate loading, commonly referred to as carb-loading or carbo-loading, is a strategy used by endurance athletes, such as marathon runners, to maximize the storage of glycogen (or energy) in the muscles. Carbohydrate loading is also used in healthcare to optimise the condition of patients prior to colorectal surgery. Carbohydrate loading is generally recommended for endurance events lasting longer than 90 minutes. Many endurance athletes prefer foods with low glycemic indices for carbo-loading due to their minimal effect on serum glucose levels. Low glycemic foods commonly include fruits, vegetables, whole wheat pasta, and grains. Many marathoners and triathlon participants have large pasta dinners the night before the race. Since muscles also use amino acids extensively when functioning within aerobic limits, meals should also include adequate protein. Large portions before a race can, however, decrease race-day performance if the digestive system has not had the time to process the food regimen.
