How Often Should You Fuel During Long Runs?

Practical Applications In Your Training

With scientific evidence supporting long runs in both the fasted and glycogen loaded state, how do you decide which is best for your marathon performance? My suggestion is to methodically utilize both approaches in your training.

You should run your early training segment long runs in a glycogen depleted state. This will teach your body to boost glycogen stores and increase fat as a fuel source early in the training cycle. However, because the long runs won’t be too long, you don’t run a high risk of bonking and sacrificing a critical 20 or 22-mile long run.

Run your last three quality long runs in a glycogen-loaded state. In doing so, you will increase the overall quality of these important long runs, enabling you to finish faster, and recover more quickly. Likewise, you can practice your marathon nutrition strategy to acclimatize your stomach to processing simple sugars and fluids efficiently.

By implementing both glycogen-depleted and glycogen-loaded long runs, you can improve the critical fuel efficiency element of the marathon while maintaining consistency in your training.

Do you have questions about how to incorporate these types of long runs in your training? Let us know in the comments section and we’ll get back to you faster than Usain Bolt runs the 100 meter dash!


Rapoport, B. (2010). Metabolic factors limiting performance in marathon runners. Plos Computational Biology, 6(10), e1000960.

Burke, L. (2007). Nutrition strategies for the marathon: fuel for training and racing. Sports Medicine, 37(4-5), 344-347.

Stannard, S., Buckley, A., Edge, J., & Thompson, M. (2010). Adaptations to skeletal muscle with endurance exercise training in the acutely fed versus overnight-fasted state. Journal of Science & Medicine in Sport, 13(4), 465-469.

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