Carbohydrates are basically sugar and starch. Apples, oranges, potatoes, grains, candy, bread… are all carbohydrates. Carbohydrates break down into glucose molecules. When used as energy, carbohydrates fuel become fuel for your muscles and brain. If your body does not have any use for the glucose, it is converted into glycogen and stored it in the liver and muscles as an energy reserve. Your body can store about a half a day's supply of glycogen. If your body has more glucose than it can use as energy, or convert to glycogen for storage, the excess is converted to fat.
Carbohydrates are divided into these two categories.
You can maximize glycogen storage by eating smaller and more frequent carbohydrate meals. Eating less food, more frequently, and cutting down on protein and fat will provide a steady supply of glucose to your muscles. This will aid in muscle recovery after exercise, as well as help you "load" carbs before a workout or climbing competition. See also Carbohydrate Loading for competition and endurance gains.
So, the amount of carbohydrate you eat determines the amount of glycogen stored in the liver and muscles, which in turn greatly affects your performance level. When you eat foods like fruit, cereal, or bread, glucose goes into your bloodstream quickly, ready to provide immediate energy to the brain, muscles, or other body tissues demanding energy. If glucose is not used right away, it is converted and stored in the liver and muscles as glycogen.
If you eat a low carbohydrate diet, it is less efficient for your body to store glycogen in your body. You may especially notice an energy drain if you do not take days off from your workouts routine. A glycogen drain will make you may feel listless and uninterested in exercising. You need to take a few days off from your work out to allow your body to recharge the glycogen stores.
Some climbers eat very little - or go without food altogether before a climbing competition. They think they will be lighter and therefore climb better - the fact is, reducing carbohydrates before a climbing competition will cause your endurance to drop by almost half. The end result is far worse on your performance than the effect of being a little bit lighter in weight. Cutting back on food the day before only uses up your precious glycogen stores. It takes less than 24 hours of fasting to completely drain your liver glycogen stores. Carbohydrates are the brain and muscle's fuel, so your body needs to use carbs even while you sleep. Even if you skip dinner the night before, your glycogen stores will be slightly less the next morning.
When you reduce your carbohydrate calories, your body will start to use up glycogen stores. Low glycogen forces your body to switch to using more body fat for energy and begin converting amino acids from proteins to fuel. Using fats and amino acids this way is inefficient - it pulls amino acids away from proteins. This has additional negative effects and potentially weakens your immune defenses. The amino acids and minerals found in protein are necessary in muscular development. Large amounts of protein is not necessary. Carbohydrates, especially complex carbohydrates are the most effecient fuel source for muscles and brain.
Long stretches of time depletes both your glycogen stores and vital body water lost as sweat. It takes anywhere from 24 to 48 hours for full recovery, provided you are eating a high carbohydrate diet and consuming plenty of fluids. An average man who weighs 160 pounds, for instance, needs about 2,400 carbohydrate calories to fill up his glycogen tanks. This represents 600 grams of carbohydrate, the amount found in 40 slices of bread. Eating this large amount of carbohydrate is usually manageable over a 1 1/2- to 3-day period. One gram of carbohydrate equals 4 kilocalories and a kilogram equals 2.2 pounds.
Eat carbohydrate within one hour after exercise. Research studies show that you can expect to achieve full recovery of glycogen stores only if you begin carbohydrate reloading almost immediately after exercise.
The more carbohydrate you eat, the more glycogen you store. This process will continue until your full capacity is achieved. The key to keeping your glycogen stores filled is easy:
Summary: Carbohydrates efficiently replace the glycogen stores in the muscles and liver. Glycogen is necessary for muscle contraction. If you do not eat enough carbohydrate or get enough rest, the level of glycogen steadily declines, leaving you fatigued and unable to perform effectively.
Books about Nutrition and Carbohydrates: