The Skinny on Sugar

By Scott Dwyer
Dec 23, 2005, 09:23

We have all looked at a nutrition label to find out exactly how much sugar our mid-afternoon snack has or have opted for a diet drink, because regular ‘has too much sugar’. But what exactly are sugars and what role do they play in an athlete’s diet?

Sugars are simple carbohydrates, and although there are numerous sugars that exist, there are a few that stand out in the athletic diet. First and foremost is glucose. Also known as blood sugar, or dextrose, glucose is a main source of energy for the body and the only source of energy that can be used by the central nervous systems. Fructose, or fruit sugar, is another monosaccharide (single sugar) the body uses after it is converted to glucose in the liver. Sucrose, an important disaccharide (double sugar) is a polymer of glucose and fructose and is easily recognizable to most of us as common table sugar. Maltodextrin is a polysaccharide (multiple sugar), a long-chain polymer of glucose. It is important because it provides glucose for energy, but as a long chain polymer, it does not have the sweet taste that is characteristic of the other sugars mentioned. All of these sugars are high glycemic index (HI GI) carbohydrates, meaning that they will cause a rapid increase in blood sugar. As an athlete, this is important for both “quick energy” during exercise and muscle glycogen restoration after exercise.

During exercise an athlete should be consuming about 30-60 grams of carbohydrates per hour. This applies to both training and racing events. A good portion of these carbs should be HI GI, especially later in a workout, and easily digested and absorbed into the body. Sugars are perfect for this. In most sports drinks, bars, and gels, including PowerBar products, you will find some combination of the sugars discussed previously. The key to differentiating between all of these products is to look at what specific combination of sugars they are using. All four sugars have been individually proven to increase performance when consumed during exercise; however a combination of sugars will have a synergistic effect. Fructose alone can be hard to digest and can even lead to GI disturbance, while glucose alone does not give the maximum amount of performance increase. When glucose and fructose are combined, they lead to the largest increase in performance.

It is also important to consider that for optimal rate of carbohydrate absorption to occur there must be an appropriate amount of sodium present.

This combination of sugars can also be found in most post exercise recovery drinks. The ultimate goal of these drinks may be different form sports drinks, but the concept is the same: rapid carbohydrate digestion and absorption. The quicker carbohydrates are absorbed after exercise, the faster muscle glycogen restoration will take place.

Sugars are not only beneficial to the athletes in the form of powder and gel. There are lots of sugar-containing foods that are essential to an athlete’s diet as well. The energy that comes from fruits and vegetable is derived from sugars. This does not mean that we can replace our daily servings of broccoli with cupcakes. Fruits and vegetables are nutrient dense; their sugars arrive in our bodies together with water, fiber and, and many vitamins, bioflavonoids and minerals. It is the foods that have large amounts of refined sugars and very few nutrients that you should be cautious about. Refined sugar is delivered in a concentrated form to the body, almost completely devoid of nutrients. 

They key to eating the right sugars is knowing what your body needs and when it needs it. During exercise, foods that contain a combination of at least two of the aforementioned sugars (glucose, fructose, sucrose, and maltodextrin) will quickly provide you with clean-burning energy. When snack time comes around, fruits and vegetable provide energy as well as the important nutrients your body needs. Refined sugars and nutrient-barren foods are fun and sometimes a tasty treat, but they shouldn’t make up a significant part of an active person’s nutrition program. Stick to the right sugars and you’ll have all the energy you need for a productive day and a great workout.

Scott Dwyer is a Resident Coach with Carmichael Training Systems, Inc. (CTS). He graduated from Virginia Tech with a BS in Human Nutrition, Foods, and Exercise; and competes in events ranging from sprint triathlons to expedition-length adventure races. To find out what CTS can do for you, please visit http://www.trainright.com.

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