Carbohydrates (Carbs) are pure fuel. Your body stores them as glycogen in the muscles and liver. Each gram of carbohydrate provides four calories of energy. At any one time you have about 400 to 500 grams or 2,000 calories worth of carbs stored and available to fuel your activity.
Carbs provide fast energy for your muscles because your cells can convert stored glycogen and glucose (blood sugar that is created when your body breaks down the carbs you eat) very quickly. The higher your exercise intensity, the more carbs you burn. Your body also uses some carbohydrates to assist with fat burning during lower-intensity exercise.
You’ll deplete your glycogen stores after two to three hours of continuous low-intensity training or within 30 minutes of very high-intensity training. During long rides, you can maintain your energy levels by taking in 30 to 60 grams (120 to 240 calories) of carbohydrates per hour after the first 90 to 120 minutes.
These foods contain carbohydrates: Dairy, Fruit, Grains, Legumes, Starchy Vegetables, Sugary Sweets.