When you run your body needs energy. This energy comes from what you eat and what you drink. The body's preferred source of energy is carbohydrates that are stored in your muscles and liver as a 'fuel' called glycogen.

The body's glycogen stores are limited so, as a runner you need to ensure you eat plenty of carbohydrates to keep these stores topped up. When you are training, at least 60% of your daily calorie intake should come from carbohydrates (e.g. pasta, rice, bread, cereals and potatoes).

However, you should not base your carbohydrate intake on percentage alone, this is a good indicator, but it is best to also follow the below* suggested guidelines, which are based on grams per kilogram of body weight.

• Moderate duration/ low intensity training: 5-7g per kg per day
• Moderate to heavy endurance training: 7-12g per kg per day
• Extreme exercise performance: 10-12g per kg per day

Further information and advice

• Carbohydrates - The Facts
• Dehydration - The Facts
• Caffeine - The Facts
• Hydration - Is your body getting the fluid it needs?
• Runners' Training Pack

References:
*J Sport Sciences 2004; 22 57-63
**1. Murray, R. (1998). Rehydration strategies-balancing substrate, fluid, and electrolyte provision. International Journal of Sports Medicine 19(2S):S133-135
Food and Nutrition Board / Institute of Medicine (2004). Dietary Reference Intakes: Water, Potassium, Sodium, Chloride, and Sulfate . National Academy Press, Washington , DC . p.105-111.
*** In house/ unpublished data.

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