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From Florida, USA:

My son, 15 years old, has had diabetes since 7 1/2 months. He is such a good boy. A great student and athlete. He races off road mountain bikes (actually in Florida it should be hill bikes). I need nutrition help. Do you know of any research centers that I could e-mail? We need to figure out when he should eat before a race and what he should eat. He trains hard, but can't keep up with friends, and being a teenager, and exercising so much, he has started to eat "junk" food. I tell him he needs to eat twice as healthy as his friends as his body is already stressed. We have no medical help around here who are avid exercisers - it has to be more than a nutritionist telling us "oh, just eat carbs." It's also a matter of timing. I want to learn more. Do you know any books?


First things first: Be sure that your son is in good control of his diabetes and that he checks his blood glucose levels before and after exercise. An exercising body uses carbohydrate as it's main fuel source. Carbohydrate, stored in the muscles and the liver as glycogen, breaks down and circulates in the blood stream as glucose. Remember, the effect of exercise will depend on whether enough insulin is available to allow the muscles cells to use glucose for energy.

Food intake may need to be increased to accommodate his off road mountain bike races. Regular periods of activity should already be planned for in his meal plan. Well-trained individuals who exercise regularly will usually need less added food than individuals who exercise only occasionally. Be careful not to eat too much food before exercise.

Guidelines for increased food should be based on blood glucose levels before and after his off road mountain bike races and on how close to regular scheduled meals and snacks the races occur. The effect of exercise on blood glucose levels varies greatly! Everyone exercises at different intensities and uses insulin and food differently.

Here are some general guidelines that may be of some help to you and your son:

  1. On the day of his off road mountain bike races, he ml>
  2. On the day of his off road mountain bike races, he may want to eat a light breakfast, such as toast, juice or fruit, and cereal with skim milk.

  3. If blood glucose is below 100 ml/dl, a snack should be eaten before exercising. In general, 10 to 15 grams of carbohydrate (one fruit or starch exchange) should be eaten before exercise of moderate intensity lasting for about 1 hour. Examples of moderate intensity exercise are tennis, swimming, jogging, cycling.

  4. For more strenuous exercise, such as Phil's off road mountain bike races lasting 1 to 2 hours, 30 to 50 grams of carbohydrate (1/2 meat sandwich with 1 milk or fruit exchange should be eaten).

So in essence, a light pre-event meal should be eaten 1 to 2 hours before starting time of your son's off road mountain bike races. The meal should contain mostly carbohydrate and some protein, but a minimal amount of fat.

Athletes with diabetes often become so preoccupied with replacing carbohydrates that they forse, let alone an off road mountain bike race: water!

Here are a couple of references that may be of some benefit to you:

  • Nutrition and Sports Performance: A guide for Physically-Active Young People, a pamphlet put out by the American College of Sports Medicine, P.O. Box 1440, Indianapolis, IN 46206-1440

  • In Control -- A Guide for Teens with Diabetes by Jean Betschart, M.N., R.N., C.D.E. and Susan Thom, R.D., L.D., C.D.E. ISBN 1-56561-061-X.

Lastly, just as your son practices his off road mountain bike racing skills and builds his endurance level which will lead to better performance, learning his insulin and food needs and his response to exercise will be a major part of reaching his athletic potential.


Original posting 18 May 97


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Last Updated: Tuesday April 06, 2010 15:08:54
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