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Sugar and Performance

by Kim Wathen, M.S. Exercise Phys/Dietitian

New evidence suggests that sodas sweetened with high-fructose corn syrup may increase the risk of diabetes, particularly in children. (Credit: American Chemical Society)

How much sugar did you consume today? How much should you consume per day? What effects does sugar have on you? Does sugar make a difference in your performance on and off the bike? While Americans consume considerable amounts of this substance, many of us could not answer these questions.

The average American consumes 20 teaspoons of added sugar each day. This is double the USDA’s recommendation of no more than 10 teaspoons of added sugar per day. Sugar is readily available in many forms and is present in a vast number of foods we eat. It is found on ingredient lists under many names so it isn’t always obvious to the consumer. Sugars are often referred to as “simple” carbohydrates because they are smaller molecules than starches, which are “complex” carbohydrates. The major sugars (listed in order of relative sweetness) are:


Relative Sweetness (comp. to sucrose)

Fructose (fruit sugar) 170
Sucrose (table sugar) 100
Glucose (dextrose) 70
Maltose 46
Lactose (Milk Sugar) 35
Galactose 32

Fructose, sucrose, glucose and maltose are all derived from plants, while lactose and galactose are found in milk and milk products.

Once consumed, the body converts sugar to “blood sugar” or “blood glucose”, to be used as energy. How quickly blood sugar levels are affected depends on several factors, but in general simple sugars will raise a persons blood sugar more quickly. The effect that food has on blood sugar levels is referred to as the “glycemic effect”. Although it may seem that this glycemic effect may not be important to your riding and racing, it can have a big impact on your performance.

Optimal functioning, especially during athletic events, is only possible when blood glucose is within a certain range. Normal levels fall between 70 and 150 mg/dl. Levels are typically lower in the morning and higher after meals. If your blood glucose concentration falls below normal, you may become dizzy, tired, hungry and shaky; if it goes above normal you may become sleepy. If glucose levels reach extremely high or extremely low levels, you will end up in a coma.

Because sugar can have a significant impact on blood glucose levels, using it conservatively and paying attention to when it is consumed will have positive effects on your performance both on and off the bike. Sugary foods and drinks can cause spikes in blood glucose which are often followed by sharply falling levels. When these low levels occur we are often driven to eat sugary, salty, and/or high fat foods. This will not only sabotage your fitness/nutrition plan but can also affect performance. To avoid these spikes and “crashes” it is best to avoid eating or drinking sugary foods by themselves. If you do consume something sugary, combining it with lower sugar foods will lessen the impact. Eating every two to three hours will also help keep glucose levels within normal limits.

Cytomax Recovery contains sugar and carbohydrates which provide the energy sources to restore muscle and liver glycogen

Consuming sugar like that found in Energy Drinks and Sodas shortly before a moto or other exercise will often cause cramps, nausea, diarrhea and bloating. However, sugar consumption during a bout of exercise can improve performance provided the sugar is sucrose (table sugar) or glucose. Fructose (sugar from fruit) has been shown to cause gastric distress when consumed during exercise so it may harm performance. Although drinking sugars during a moto is not possible, you can maintain your blood glucose levels by using sport drinks like Cytomax between your races. These drinks contain primarily glucose and sucrose.

After heavy exercise it is beneficial to replenish the body’s storage form of glucose or glycogen. This is best done by consuming sugars with a high glycemic effect within 15 minutes after exercising. Sucrose and glucose both have a high glycemic effect, and are commonly used in sport drinks and recovery drinks.

Sugar in any form contains about 20 calories per teaspoon, and provides no nutrition (with the exception of some “natural” sweeteners which contain trace amounts of vitamins and minerals) so should be used sparingly. If you are eating high amounts of sugar it begins to take the place of other more nutritious foods you should be eating. Those extra calories provided from high sugar intake along with the high fat content of many sugary foods can lead to obesity. There is some evidence that high fructose corn syrup, which is now being added to many foods, leads to obesity and researchers are also linking it to diabetes in kids. Be especially careful not to buy foods with this ingredient, especially if it is close to the top of the ingredient list.

Check out this website for a comprehensive list of sugar content in common drinks:

Honey is often said to be healthier than other sugars but this is not so since all sugars, including honey, must be converted into glucose before the body can use them. Natural sugars typically have less effect on blood glucose which helps avoid the spikes and crashes mentioned above. Brown rice syrup and barley malt have the highest nutrient content of any natural sugars and have less effects on blood glucose. To learn more about natural sugars click here.

Points to Take With You

  1. Consume sugary foods in moderation.
  2. Limit intake of foods with sugars (especially high fructose corn syrup) listed high on the ingredient list.
  3. Get no more than 20% of your calories from sugar.
  4. For optimal performance, keep blood glucose levels within normal limits by eating every 2-3 hours and only consuming high sugar foods along with less sugary foods.
  5. Don’t consume sugary foods and drinks within 2 hours before exercise or riding.
  6. Use sport drinks containing glucose and/or sucrose within 15 minutes after exercise or riding to replenish energy stores and to re-hydrate.  This can be done up to 2 hours after exercise, but if done within 15 minutes will be much more effective.

That's it for now, until next time, good luck with your training and remember, if you have a question, log on to the Virtual Trainer Expert Forum and have your question answered by a panel of experts. In addition, be sure and check out the Racer X Virtual Trainer archive section. Your complete one-stop information zone for motocross fitness. VT Signature

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  1. Gravatar
    Bradley Segal May 10, 2010 at 7:25 am

    my trainers no.1 top tip for sugars...

    use honey and anything containing fructose because it gives you a later delayed energy boost compared to glucose, glocose is used up quickly by the body and is oftern stored and fructose gives a delayed energy release over a period of time.

    eg. . before a race eat somthing containing carbs and fructose.. such as honey on bread etc... simple things like that work like a charm :)

  2. Gravatar
    Racer X Virtual Trainer May 10, 2010 at 8:22 am

    Yep, for sure. Honey on Whole Wheat bread is a great pre-race snack. Thanks for the tip Bradley.

  3. Gravatar
    Bradley Segal May 10, 2010 at 10:24 am

    It's a pleasure.

    another really good pre-race snack (only if you can stomach it, its really gross)
    is a small 250ml plain yoghurt with half a cup of cornflakes, a teaspoon of honey and a tea spoon of (this is where it gets gross) cod-liver oil.

    its all good for you but man it tastes really bad :P

  4. Gravatar
    Racer X Virtual Trainer May 10, 2010 at 2:46 pm

    You had me up until the Cod Liver oil!

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