Nutrition - Carbohydrates
Carbohydrates are the main source of energy for an athlete. Carbohydrates are found in most foods, primarily in plant derived foods like fruit, vegetables, pulses and grains.
There are two kinds of carbohydrate:
- simple carbohydrates; sugar, soft drinks, cake, candybars
- complex carbohydrates; cereals, bread, potatoes, pulses
All carbohydrates are converted into glucose for immediate energy and into glycogen* for energy reserves. In general, simple carbohydrates are hydrolysed faster than complex carbohydrates. Simple carbohydrates provide “fast” energy, complex carbohydrates provide more continuous energy.
Carbohydrates are stored in muscle as glycogen. An average person can store about 400 grams of glycogen (1/3 in liver, 2/3 in muscles). By eating a diet high in carbohydrates and a proper training build-up, trained athletes can achieve glycogen stores of up to 800 grams.
Emptying and replenishing of glycogen is limited to the muscles which are active during exercise. For example: a right-handed handball player will mainly empty her right arm, a marathon runner will mainly empty his legs. Because the local glycogen store in the dominant working muscles is always empty first, the glycogen store is the performance-limiting factor in high intensity exercise (> 45 minutes).
When glycogen stores are low, proteins and fat will also be used for energy supply. When glycogen stores are depleted completely, the body can only use fat and protein for energy. In this case, your performance will decrease to 50% of your maximum.
This problem can be solved by using a carbohydrate-rich nutrition and replenishing carbohydrates during exercise. Therefore, carbohydrates are indispensable in an athlete’s diet.
eat mainly complex carbohydrates.