Your brain, muscles and all the other cells in your body depend on carbohydrates for their primary source of energy. You need a regular daily supply, and a minimal amount of carbs, to stay active and healthy. Besides consuming a sufficient amount, it’s also important to meet your daily requirements with healthy, complex carbs, such as fruits, vegetables, beans and whole grains.
Carbs for Energy
When you eat carbohydrates, they’re digested into glucose, which is the form of sugar cells use for energy. Any glucose you don’t need for energy is stored as glycogen or fat. While fat can be metabolized back into glucose, glycogen has a more important role for sustaining optimal energy. It’s immediately available and quickly converted back into glucose as soon as your activity level increases. Your body has limited storage space, retaining only 2,000 calories, or 500 grams, of glycogen. About 400 grams of the total glycogen stored stays in, and is devoted to providing energy for, your muscles, according to Iowa State University Extension and Outreach.
Total Carb Recommendation
The two types of carbs that provide energy are sugar and starch. They both consist of molecules of sugar, but starches contain many thousands of molecules connected in complex shapes, while simple sugars consist of one to three molecules, according to Colorado State University. Since sugars are small, they’re quickly digested and absorbed into your bloodstream. During digestion, starches must go through several steps before they're broken down into individual sugar molecules. As a result, they take longer to enter your blood. The recommended dietary allowance for total carbohydrates is 130 grams daily, or 45 to 65 percent of your total daily calories, according to the Institute of Medicine.
Dietary Fiber Requirements
Fiber also contains thousands of sugar molecules, which are connected by a very strong bond. Your body does not have the enzymes needed to break apart these bonds, so the two types of fiber -- soluble and insoluble -- pass through your digestive system intact. Soluble fiber absorbs water, which makes you feel full and slows down the rate at which sugar enters your bloodstream. It also helps prevent cardiovascular disease by helping to lower cholesterol, according to Oklahoma Cooperative Extension Service. Insoluble fiber keeps wastes moving through your digestive tract. The Institute of Medicine recommends 25 grams of fiber daily for women and 36 grams daily for men.
Stored Carbs Support Activity
When your activity level increases, your muscles depend on their stored glycogen for energy. If you engage in endurance sports or other intense activities, you may need to boost your daily carb intake. You'll maximize glycogen storage by eating carbs prior to exercise and you should replenish glycogen with carbs after you exercise, notes Iowa State University Extension and Outreach. For light to moderate athletic training, the Academy of Nutrition and Dietetics recommends consuming 2.3 to 3.2 grams of carbs per pound of body weight. During high intensity training, increase it to 3.2 to 4.5 grams per pound, and if you train for more than four to five hours daily, go for 4.5 to 5.5 grams of carbs per pound.
- Iowa State University Extension and Outreach: Role of Carbohydrates
- Colorado State University: Dietary Polysaccharides: Structure and Digestion
- Institute of Medicine: Dietary Reference Intakes: Macronutrients
- Academy of Nutrition and Dietetics: Eat Right for Endurance
- Centers for Disease Control and Prevention: Carbohydrates
- Oklahoma Cooperative Extension Service: Dietary Fiber