Can I Carb-Load with Diabetes?

Q I am a 50-year-old male and was recently diagnosed with diabetes. I have run on and off my entire life but have started running very seriously, enough so that I have registered for my first ever half marathon. I have seen many articles about runners and carb-loading, both in training and for the actual race. I am concerned that with my diabetes, carb-loading might not be my best option. What are the best foods for me to be eating? My race is in 22 weeks and I have just started a 20 week (plus two extra) training program. It is important to me that I complete the training and the race but it’s also just as important that I eat properly for my condition. – M.


A This is a great question that affects many who have the diagnosis of diabetes. I am going to assume from your age and the recent diagnosis that you have type 2 diabetes and that you are in reasonably good control. When you look for information on your question, there is not a lot out there to give you a definitive answer. Although we are getting better at finding type 2 diabetes earlier, the condition is often present for several years before the diagnosis is made. It is important to have an evaluation with your physician before you take on higher level exercise like training for a half marathon to make sure you do not have cardiovascular disease or other problems associated with diabetes and that your medications are the best for more intense physical activity.

Type 2 diabetes involves insulin resistance and inability to get glucose into the cells. The treatments are geared to improve the cell responses and glucose utilisation pathways. Exercise increases glucose uptake into the muscle and generally improves type 2 diabetes. Eating a well-balanced diet aimed at attaining and maintaining ideal body weight for your height will likely serve you well during your training and racing. A mix of complex carbohydrate, protein and healthy fats (from nuts, avocado and fish) should be good for you. An increase in your carbohydrate load the day prior to your race should be adequate to fuel your race.

The mainstay of medical treatment for type 2 diabetes is metformin when diet and exercise alone have failed. Metformin works by enhancing peripheral glucose uptake, decreasing glucose production in the liver, and increasing insulin sensitivity. This medication rarely causes hypoglycemia so it is a good one for those who exercise, but do not have adequate control from diet and exercise alone. You will likely develop your race day nutrition strategy during your long runs as your prepare for the race. You might try different carbohydrate loads the evening before your longer training runs, although the most important part of your plan will be how you replace carbohydrate during your runs that last longer than 60-90 minutes. Sports drinks during your runs may help level your carbohydrate levels available to the muscle while you are racing. Some of the gels made for racing can keep your glucose levels up to allow muscle utilisation and have the advantage of a small volume. For your usual shorter duration training days, you probably do not have to do anything different. If you are on medications that augment insulin secretion, like a sulfonylureas, you will be at more risk of hypoglycemia during your runs and you may need a different strategy.

It is prudent to carry a glucose gel tube or glucose tablets when you are on training runs and when you race to cover yourself if you become hypoglycemic. You may have to check your glucose a few times to see how the level correlates with how you feel. It will be important for you to discuss your exercise plans with your physician and maybe you would benefit from a session or two with a nutritionist who focusses on diabetes and exercise.

Bottom line, there will not be a huge benefit from carbohydrate loading, but you will need to focus on your intake during long runs.


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