Glucose, or blood sugar, is your body’s basic source of energy. You don’t need to eat glucose—your body converts any carbohydrates (sugars and starches) that you eat into glucose. If your body produces more glucose than you need at the moment, the excess is converted to either glycogen or fat for storage. How much glycogen you have stored has a big effect on energy availability and weight loss (or gain), so, depending on your health goals, you may be trying to maximize or minimize your glycogen stores.
Since part of what determines how much glycogen you have is diet, you need to know which foods have the carbohydrates you need to produce glycogen.
All About Carbohydrates
Carbohydrates are a group of substances, including both sugars and starches, that all are converted to glucose in the body. Sugars, like glucose, sucrose, lactose, and fructose, are called simple carbohydrates because they are chemically simpler and easier for the body to process than the complex carbohydrates, or starches. All carbohydrates contain the same amount of energy, four calories per gram, but differ in how quickly the body can access that energy. The glycemic index is a measure of how quickly a food causes your blood glucose level to rise—a high glycemic-index food causes a faster, more abrupt rise than a low glycemic-index food with the same number of calories.
Carbohydrates are one of the three groups of macronutrients the body needs, the other two being proteins and fats. Although the body can use all three for energy, burning protein and fat is inefficient, and both have other roles in the body besides energy. When you have more glucose in your blood than you need at the moment, the excess can be converted to either fat or glycogen. Your body can metabolize fat for energy, but cannot convert fat back into glucose. Only glycogen, a polysaccharide, can be converted back into glucose, and since there are bodily processes that can use no other fuel but glucose, you need your glycogen.
A Matter of Diet
Athletes need large quantities of glycogen, so they often eat diets very high in carbohydrates. Some research suggests that high glycemic-index foods are better for replenishing glycogen stores, so an athlete may look for foods that contain large amounts of carbohydrate and have a high glycemic index. In contrast, some forms of weight-loss diets depend on minimizing carbs of all types, while other weight-loss diets, as well as food plans for diabetes management, depend on choosing foods with a low glycemic index, even if the total amount of carbohydrate is not limited.
Recommendations for Carbohydrates
As a general rule, the Centers for Disease Control and Prevention recommends that 45—65% of your calories should come from carbohydrates, depending on how athletic you are. If you are eating a 2,000 calorie diet, that translates to 225 to 325 grams of carbohydrate per day—that’s the equivalent of about four or five bagels (not that five bagels per day with nothing on them would be healthy or enjoyable). Many women need fewer calories per day, and hence fewer carbs, and athletes of whatever sex often need more, sometimes much more.
Fruit and whole grains are healthy sources of carbohydrates, as a general rule, but not all are equal in quality.
Fruits and Vegetables
Most fruits and some vegetables are high in natural sugar, meaning both that they have lots of carbohydrate and a very high glycemic index. Fresh fruit and vegetables are also good sources of vitamins and many have plenty of fiber, which is good for your digestion and helps you feel satisfied for longer. If you’re trying to pile on the carbs, fruit is a good way to do it. If you’re trying to minimize carbs, fruit still makes a healthier treat than cake or candy.
Fresh fruit and vegetable juice has all the same carbohydrates and vitamins as whole fruits and vegetables, but without some of the fiber, so it’s easy to consume large amounts fast. Only a glass or two of juice is the equivalent of all the fruits and veggie you might eat with a whole meal. Be sure to look for 100%. A lot of juice-based drinks contain added sugar, and the type of sugar added is usually less healthy.
Potatoes, sweet potatoes, squash, and a number of other vegetables are high in starch, a complex carbohydrate, as well as vitamins and fiber. Complex carbohydrates often have a lower glycemic index than simple carbohydrates, though you have to look up the individual food to be sure.
Grains are very high in starch and generally have some sugars as well. If you want to shovel in the carbs, grains are a way to do it. However, processed grains, such as white breads or pasta, lack fiber, and many have very high glycemic indices. Whole wheat breads and pastas have more fiber and vitamins and are generally healthier. Whole, unprocessed grains, such as barley or quinoa, have more fiber and more protein, and often have lower glycemic indices, too.
Oatmeal is a great source of complex carbohydrate, but it also has a very low glycemic index and is good for helping to keep blood sugar stable. If you want to add more carbs to your meal, oatmeal tastes great with honey and fruit.
Yogurt is a good source of both carbohydrate and protein, although yogurt products can vary dramatically in both added sugar and fat. Some experts recommend low-fat yogurts for athletes specifically.
Athletes sometimes practice carb backloading, meaning that they time their consumption of carbohydrate for periods when the body is most likely to store the extra glucose as glycogen rather than as fat. If this is news to you, check out the article, Carb Load Diet for Beginners.
For backloading pros, there are carb-load supplements that many athletes use to help with energy and muscle building. Try Carb Load Boost™ to help your carb-load diet do wonders for your body.