Carbohydrate loading
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In sports, carbohydrate loading, also known as carbo-loading, is a strategy employed by endurance athletes such as marathon runners to maximize the storage of glycogen in the muscles.
The protocol of carbohydrate loading was originally developed in 1967 by Swedish scientist Gunvar Ahlborg. The original theory of carbohydrate loading was that, if the body's glycogen stores were depleted, it would store more glycogen than normal when carbohydrate intake returned to normal. Consequently, the original carbo-loading regimen began one week before the event, and called for three days of minimal carbohydrate intake (about 10% of total calories) and intense exercise to deplete the body's carbohydrate stores. Then for the next three days, the athlete would consume primarily carbohydrates (about 90% of total calories), and reduce the intensity of exercise to allow for maximum storage.[1]
In the 1980s, further research led to a modified carbo-loading regimen that eliminates the depletion phase, instead calling for increased carbohydrate intake (to about 70% of total calories) and decreased training for three days prior to the event. [1] Most athletes now follow this modified regimen, and it is recommended by many coaches, although there are some athletes who still follow the original carbo-loading regimen.
A new carbo-loading regimen developed by scientists at the University of Western Australia calls for a normal diet with light training until the day before the race. On the day before the race, the athlete performs a very short, extremely high-intensity workout (such as a few minutes of sprinting), then consumes 12 g of carbohydrate per kilogram of lean mass over the next 24 hours. The regimen reportedly resulted in a 90% increase in glycogen storage.[1]
Carbohydrate loading is generally recommended for endurance events lasting longer than 90 minutes. For many endurance athletes the food of choice for carbo-loading is spaghetti. Because of this, hundreds of marathons and triathlons have huge spaghetti dinners the night before the race.
