Carbohydrates: The Good, The Bad and The Glycemic
The primary role of carbohydrate is to serve as an energy source, but this isn’t a revelation. Grains, legumes and rice have been dietary staples throughout history and are important enough to be mentioned in sacred texts of major religions. Scientific studies from as early as 1939 (Christensen and Hansen) linked high carbohydrate diets and subjects’ ability to perform sustained labor. Countless studies have followed and documented the effect of carbohydrate intake on aerobic performance, work capacity and intermittent activity. Carbs come in three forms, according to the number of sugar units they contain: monosaccharides, disaccharides and polysaccharides…I dated a girl named Polly once, but she wasn’t very sweet. I digress…Glucose, fructose and galactose are the single-sugar molecules called monosaccharides. In the body, glucose is the primary energy source for your cells and combines with other single-sugars to form sucrose (table sugar) and dextrose (found in sports drinks and IV drips). Fructose has the same chemical formula as glucose, but is much sweeter. It is the sugar found in honey, fruits and vegetables. Galactose combines with glucose to build lactose, which is the sugar in milk.
Lactose, sucrose and maltose are composed of two simple sugar units and are the disaccharides. Sucrose is the most common of these three and is a combination of glucose and fructose, which gives white, powdered and brown sugar its sweetness. However, if you love a cold one at the end of your day, maltose may be your favorite sugar because it is the primary carb in beer.
Polysaccharides are the “good carbs” or complex variety, which may contain thousands of glucose units. They are the starch found in grains, nuts, legumes and vegetables and must be broken down to glucose. Fiber, which is a part of a plant’s cell wall is also a form of carbohydrate, but is resistant to digestion in the human body. Glycogen is the form of sugar store in muscle and the liver and serves as a temporary energy source.
If you made it through the science…congratulations! Now let’s answer the questions you must have such as how many carbs should I have every day and what kind are best? There are two ways to choose how many carbs you should have each day and you can use the method which is best for you:
If you are a sedentary man or a woman try to obtain 14 calories per pound of body weight or about 45 – 65% of your total calories from quality carbohydrate sources. If you are a more active man and woman aim for 15-17 calories per pound of body weight or about 50 – 60% of your total calories. If you are very active as an athlete or in your job you can adjust these recommendations higher.
When deciding the source of your carbs you may want to consider the glycemic index (GI) of the food. The GI classifies a food by how high and for how long it raises blood glucose. The reference food for glucose is Bunny Bread, well, any white bread. In short, foods which digest quickly have a high GI, while foods which digest more slowly have a lower GI. Even if you do not have blood sugar challenges consuming foods with a low GI will ensure your carbs come from sources which are unrefined, have more fiber and deliver long-lasting energy.