Fasted training sessions & fat adaptation

Nutrition Q&A [Moderated]
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Hey gang, I’ve shifted focus from solely strength/competitive PL due to new objectives in the next 12-24+ months. Specifically, my new focus will be mountaineering and high-altitude performance. My BBM coach is working with me on that programming transition and that is coming along well.

Nutrition-wise, some of the top folks in the field that I respect are advocating fasted training sessions and the important need to get “fat-adapted” in terms of burning fat for muscular fuel instead of the usual carbs/sugar. They don’t mean for impacting strength and high-intensity sessions, but rather for the aerobic-oriented sessions that are the foundation for these endurance endeavors. I don’t want to misrepresent their views, as I am learning these things and have limited knowledge. See references here: Train to Burn Fat | Uphill Athlete and here: Burn Fat to Go Fast: Fat Adaptation and Endurance Performance | Uphill Athlete

The above articles have some references noted as follows:

https://www.ultrarunning.com/features/health-and-nutrition/the-emerging-science-on-fat-adaptation/

The purpose of my question is to see where this falls in your views on the research and your current stance. The reason being that I am seriously considering following suit to these recommendations for the desired outcomes (better fueling endurance, higher endurance performance, staying warmer at altitude once glycogen stores are depleted, etc.).

Jordan, I have heard your frequent responses to “intermittent fasting” and the focus on making sure folks are getting all of the suggested nutrition per the accepted guidelines (veggies/fruits/protein/fiber/etc.) and, if so, you don’t really care so much how they go about it. I believe my question is different in that it’s much more specific in terms of activity, purpose, and key details that it’s not meant to negatively impact strength- or high-intensity activities, but much more focused during certain activities for a specific outcome.

Let me know if you agree, disagree, or just meh about this topic.

Regards,
Shawn

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I do not think the top folks in the nutrition field recommend fasted training as a strategy to improve endurance performance under the guise of becoming fat adapted, as this does not seem to be a good surrogate for improved performance.

Briefly, it doesn’t seem to matter for acute workout endurance performance if you’re fasted or not anyway. It’s a coin flip and mostly personal preference…particularly if someone is well-trained.

Fat oxidation can be most dramatically increased by following a low carbohydrate diet, but the subjects’ performances drop even after time to acclimate to the diet (and ramp up fat oxidation), especially compared to the group who ate more carbohydrates (and had lower fat oxidation rates.

Yes, fitter and more-trained people tend to be able to mobilize fuel sources better than untrained folks. This doesn’t mean that we can circumvent the training process by training fasted.

Additionally, 2 of the 3 references are blog posts and the 1 scientific paper does not suggest that fasted training improves fat oxidation rates leading to better training outcomes.

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Thanks, Jordan.