What Is the Role of Carbohydrates in Energy Storage?

Carbohydrates are your body’s preferred energy source -- think of them like gasoline for your car. While your body can use proteins stored in your muscles for energy, it will first burn through your carbohydrate stores. Knowing about how your body stores carbohydrates can help you keep up with your fuel needs, particularly if you regularly engage in physical activity.

How Your Body Stores Carbohydrates

When you eat a carbohydrate-containing food, such as a slice of bread or piece of fruit, your body breaks down the carbohydrates into sugars that are then changed into glucose, according to the Iowa State University Extension. The glucose travels into different areas of your body, such as your brain or muscles, to provide energy. However, if your body has enough glucose in it already, the remaining glucose will first be stored as glycogen in your liver and cells. If your glycogen stores are full, the remaining glucose is stored as fat.

Stored Calories

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Your body stores about 2,000 calories’ worth of energy as glycogen in your muscles and liver, according to Iowa State. This translates into about 90 minutes of low-intensity exercise, such as distance running. If you are engaging in high-intensity exercise, such as a sport that involves sprinting, your glycogen stores will last about 20 minutes. Knowing how your exercise levels affect your glycogen stores can determine when and how you should eat when engaging in regular exercise.

Low Carbohydrates

If you burn through your carbohydrate stores through extended physical activity or not eating enough, your body will start to pull proteins from your muscles as an energy source. This is problematic because you can lose muscle mass and tax your kidneys, which filter the waste products from breaking down proteins. Signs you may not have enough carbohydrates stored in your body include dizziness, fatigue and weakness.

Eating Plan

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To keep your energy stores from running low and burning through your stored muscle, you can eat for energy. For example, if you will be exercising longer than 90 minutes, eating a carbohydrate-containing snack 30 minutes prior to exercising can maintain glycogen stores, according to Iowa State University Extension. An example of such a snack is an energy bar with less than 200 calories. You also should consume carbohydrates every 15 to 30 minutes during a prolonged exercise bout. Examples include energy gels, fruits or energy bars that have less than 200 calories, 4 grams of fat and 5 grams of protein. Even if you are not exercising longer than 90 minutes, you should still consume carbohydrate-rich food after exercising. This includes a fruit smoothie, 16 oz. of milk or 8 oz. of fruit juice.