Fasted endurance ride?

Searched all around for this topic and couldn’t find anything. I know you guys mentioned on an episode last year about pros going on fasted rides for like 5 hours. I’ve done some and heard somewhere that 90 minutes was either a min or a max time to go for.

By fasted, I’m referring to nothing for breakfast and going out on an endurance/“fat max” ride where you’re staying below aerobic/carb based energy sources.

What’s the shortest time that would be beneficial? Is there a max as long as you aren’t bonking?


90 was what came to mind to me too, but I can’t pull a citation from memory. There’s a big thread or two on it over at the TrainerRoad forum, over here it’s not readily endorsed over foundational changes and long-term lifestyle body comp management.

I do most tempo and endurance workouts fasted other than coffee regardless of duration as long as I don’t actually FEEL hungry, but I still have some remaining kg to lose as a priority in and out of cycling.

Unless you’re following a strict Keto diet it’s doubtful that your burning any fat doing a faster state ride even if you’ve been fasting for 12 hours. Especially a FS ride of 1-2 hrs. Your body can store up to 2,000 calories of glycogen (carbs) and even on a low carb diet, sleeping/resting for 12 hrs wouldn’t deplete your glycogen stores enough to revert to fat burning on a fasted state ride (most likely).

I have some limited experience with this, but I’d definitely be interested in the perspective of experts. I’ve done fasted zone 2 rides essentially to exhaustion. 4 hours was my limit before I reached for the clif bar and limped home. A couple observations…

  • It’s amazing how challenging zone 2 can be!
  • These are very stressful and difficult to recover from. 4 hours with no carbs is a lot for a non-pro, so I would not go any more than that. If you can lay on the couch when you get home, maybe it can work for you.
  • It takes a lot of self-discipline not to eat anything that isn’t tied down when you get home. #winninginthekitchen is hard when you have a 3000+ kcal deficit. This falls into the mentally-taxing bucket.
  • I’m not convinced that this helped me lose weight. Granted, I developed a huge calorie deficit, but I think the physiological stress / cortisol response may offset that benefit. If your diet is highly tuned and monitored maybe you can manage this better than I did
  • I became a diesel. If your race only requires sub threshold efforts, great. Otherwise, eat!

These statements are based on my experience with 3-4 hour weekend rides. Your experience may be different depending on your physiology or experience level. Again, the perspective/recommendations of those with more expertise would be interesting here!

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