Training Low Carb Training for Endurance

Low Carb Training for Endurance


Ed McNeely – Peak Centre for Human Performance

As far back as the 1960’s research has shown that dietary carbohydrate can be a limiting factor in endurance activities. As a result many endurance athletes follow a high carb diet or a diet that is designed to match carbohydrate intake with carbohydrate output.  This is based on the premise that the fuel needs of training sessions should be met with carbohydrate to prevent the oxidation of muscle tissue. While it makes a certain amount of theoretical sense there is no evidence from long term studies of trained people that high carbohydrate diets produce superior performance compared to low carbohydrate diets if similar amounts of energy are consumed.

Nutritional interventions can have a powerful effect on an athlete’s hormone profiles, recovery and training adaptations. There is a trend in true elite high performance sport to periodize nutritional programs to match the demands of the training year and the desired outcomes of the training program.

One of these interventions is to train for periods of time with reduced carbohydrate levels. Training with reduced carb levels has been shown to improve fat oxidation, enhance carb loading later, and increase the production of oxidative enzymes that are responsible for energy production in the aerobic system. In elite athletes low carb levels are usually obtained by scheduling a second training session of the day within two hours of the end of the first session. In this scenario even if the athlete does consume carbs in their post workout recovery drink they will not have time to fully replete between sessions, resulting in low muscle glycogen for the second training session.

It does take a couple of weeks of feeling a little tired and lethargic when trying a low carb training period, the results seem to worth the effort. Give it a try for a six week block and then switch back to a higher carb diet and see how it works. Make sure you keep track of your training and that for the first time that you do it over the winter, well away from race time.


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  1. Hey Ed, I’d love a little clarification on “As far back as the 1960’s research has shown that dietary carbohydrate can be a limiting factor in endurance activities.” because that goes against everything I know as an exercise physiologist.

    I think it may just be an error in my interpretation as I generally agree with the second half of your post – that low-CHO training increases the training adaptation ( even if the data seems to be equivocal so far.

    However, there is a lot of evidence that CHO intake during exercise improves exercise performance by affecting the muscle ( and even the brain (


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