WHAT IS CARB LOADING?
Carb loading is the process of maximising your glycogen stores in preparation for a long endurance event, usually something longer than 90 minutes in duration. You can only store so much carbohydrate in the body, so it makes sense to maximise those stores to delay fatigue and optimise your performance. During your event, your body can comfortably process 60g of carbohydrate per hour. This only equates to 240kcal, which wont meet the amount of calories you’ll burn, which is likely to be at least 400kcal per hour. Therefore you’ll need to be drawing on your muscle glycogen stores to keep you running or riding. Carb loading is more than indulging in a large bowl of pasta the night before. It needs to be something you focus on for the 48 hours prior to your event starting. It also isn’t eating as much as possible for the two days before your event which will only weigh you down and leave you feeling heavy and bloated.
The technique was originally developed in the late 1960’s and typically involved a 3-4 day ‘depletion phase’ involving 3-4 days of hard training plus a low carbohydrate diet followed by an increase in carbs in the final couple of days. The initial phase was very unpleasant and not always proven to help performance as it was damaging psychologically. More modern research, led mainly by John Hawley et al (1997), has found that two days of carb loading with a tapered training program, particularly in the last 1-4 days beforehand, is sufficient to boost muscle glycogen levels.
DOES CARB LOADING IMPROVE PERFORMANCE?
Muscle glycogen levels are normally in the range of 100-120 mmol/kg wet weight. Carbohydrate loading enables muscle glycogen levels to be increased to around 150-200 mmol/kg wet weight. It’s estimated that this additional amount of muscle glycogen can improve your endurance performance by 2-3%.
WHAT DOES A HIGH CARBOHYDRATE DIET LOOK LIKE?
The following diet is a meal plan for a 70kg athlete aiming to carbohydrate load:
|Breakfast||80g of oats with milk, 1 medium banana and 250ml orange juice|
|Snack||1 xmedium size baked sweet potato, slice of white fish and 500ml sports drink|
|Lunch||6 rice cakes with ham,avocado and vegetable and 200g tub of low-fat fruit yogurt|
|Snack||Banana smoothie made with low-fat milk, honey and fruit cereal bar|
|Dinner||1 cup of creamy sauce 120g of chicken, 2 cups of cooked rice and 250 ml of orange juice|
|Late Snack||Toasted bagel with jam and 500ml sports drink, spoon of fish oil|
Carbohydrate loading will most likely cause body mass to increase by approximately 2kg. For every extra gram of glycogen stored you will also store 2 grams of water. This can be a concern for many runners, but the potential negatives of setting off slightly heavier are far outweighed by the potential performance benefits.