Understanding Carbs by Sarah Gilmore
[This is a guest blog by one of our Athletic Interns, Sarah Gilmore, an Exercise Science student from UNC]
When the term “carb” is mentioned what are the first things that come to mind? Pasta? Bread? Potatoes? These are all indeed sources of carbohydrates in the average diet but they are not the only sources nor are they necessarily the best ones. The media has trained consumers to acknowledge whole wheat and whole grain as the best choice of carbohydrates. These options are better than white bread for the average meal but instead of solely focusing on looking for these whole grain/wheat foods in their diet, consumers need to be retrained to look at carbohydrates as either simple or complex.
Scientifically, a carbohydrate is identified as an organic compound that consists of only carbon, hydrogen and oxygen atoms. Carbohydrates are then generally classified into two groups: simple carbs and complex carbs based on their composition. What difference does this make to an athlete/exerciser? Simple carbohydrates are smaller strings of atoms that are readily available as an energy source to the body. While this may sound like an ideal thing to have right before exercising that is actually not the case. Because simple carbohydrates are so readily available, they are used up quickly giving athletes that instant high followed by a crash when the supplies have been depleted. Instead simple carbs are best after a workout when the muscles are damaged and benefit from the quick energy supply to immediately repair the muscle and replenish the glycogen supply that has been depleted. Complex carbs are the types of carbs best to eat before exercising as well as throughout the day. The reason for this is that complex carbs are more difficult to break down into an energy supply so they provide energy for longer. A good analogy for this relationship is that of fire fuel. Newspaper and dry leaves burn and are used up very quickly. When cooking with logs on the other hand, it takes a lot longer to get the fire going but once started it will continually burn for a long period of time. It’s the same with the simple and complex carb energy supply. Simple carbs immediately use up all the energy, which can be good if you need an immediate energy supply such as for a diabetic needing sugar or after exercising and complex carbs provide a smaller, continual source of energy, which is better when partaking in a long sporting event or carrying on daily life between meals. Simple carbs include foods such as sugar, milk, fruit, candy and soda. Complex carbs include vegetables, whole wheat/grain products, and beans/lentils.
As always, there are exceptions to the rule and some foods classified as simple carbs based on their composition actually burn energy longer than some foods classified as complex carbs. So while simple/complex is a better way of looking at food than just whole-wheat vs. not, the best way of looking at food is based on its glycemic index (GI). The glycemic index is established based on research evaluating how quickly certain foods affect the level of sugar in the blood stream. Higher glycemic foods enter the blood steam more quickly but as described before are depleted more quickly and may led to the crash. Since the average consumer will not memorize or know the GI for every food the differentiation between simple and complex carbs will suffice but a quick chart of some GI values is included below.