Carb loading is a method that is used by endurance athletes that are competing in a high intensity exercise that lasts longer than 90 minutes. The purpose of carb loading is to improve athletic performance. This is done by forcing your body to store more glycogen (storage form of sugar) for energy. The carb loaded muscle can store about 35-40 g of glycogen/ per 100g of muscle vs 32g of the same trained muscle.
How this is done:
There are several ways to carb load your muscles. Traditionally 7 days before the competition you would deplete the muscles of glycogen by performing exercise to exhaustion. For the nest 3 days you would eat a low carb diet with a low level of exercise intensity. Then the 3 days from the event the diet switches to high carb. (70%) This forces to muscles to take on as much glycogen as possible.
More recently the depletion phase has been discontinued. Carb loading works best when your diet has already been rich in carbs (3g per lb of body weight) because the body learns to more effectively use and store carbs. Three to four days before the event the carbs are increased to about 70% of your daily intake or 4-4.5 g/ lb of weight. For example if you are 160 lbs then you should take in about 650g of carbs a day divided into meals and snacks. Also to ensure that you are not depleting your glycogen stores your exercise will have to be tapered as well. It is important to mention that you should maintain a diet that contains .6- .7g of protein per lb of body weight. You may have to have 2 small servings of protein foods each day in addition to the protein you receive from daily meals. Fats should be kept to 20% of your intake.
Disadvantages:
With the benefits that come with increased performance there may also be disadvantages.
1. Weight gains. It is estimated that 1g of glycogen stores 2.7g of water. Therefore a well conditioned carb loaded athlete may be about 4 lbs heavier at the start of the race.
2. Digestive discomfort. Foods high in fiber may need to be decreased a few days before the event as will as any “gassy” vegetables. Also don’t try a new food or supplement on the day of the race.
3. Blood sugar levels. Carb loading may affect an individuals blood sugar levels, especially if you have diabetes.
Even if you carb load before a race remember that you still need to replenish then during the event to maintain your blood sugar levels and prevent “Bonking”. It is recommended that 25-60g of carbs be consumed each hour if you are exercising greater that 60 min. These carbs should come from a variety of sources to better absorption rate.
