My daughter is 10 and was diagnosed with Type 1 diabetes a year and a half ago. She takes three injections a day, combining Humalog and NPH. She is on the swim team and for swim meets the coaches recommend carb loading the night before. What is the logic behind that and is that something a diabetic can or should do?

Carbohydrate loading, a particular combination of diet and exercise training, is commonly used by serious endurance athletes (physical activities that last longer than 1hour and are performed at high intensity). Carb loading, done correctly, results in improved performance and increases “time to fatigue” by increasing liver and muscle glycogen stores. In other words, the liver and muscles are “packed” to capacity with stored sugars, to be used during the upcoming intense endurance exercise. For those involved in activities lasting less than 75 minutes, normal levels of stored glycogen are more than adequate to sustain exercise. Normal levels can be assured by a well balanced diet — ingesting 60% of the daily caloric intake (7 grams per kg body weight) as carbohydrates.

Endurance athletes (i.e., marathoners and triathletes) with diabetes certainly can and do practice carb loading, however they also must know how to match insulin levels to the increased carb intake to keep blood sugars optimal. The other important concern, and particularly for those of us with diabetes, is maintaining optimal blood glucose and hydration levels during exercise. This is probably more important in your daughter’s situation than the carb loading. In athletes, ingesting carbohydrate at a rate of 30-60 grams per hour during exercise has been shown to improve exercise performance. This should also assist in avoiding insulin induced low blood sugar. Best of luck to your daughter on her swim team participation!

DMW