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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I think doing this can help you become fat adapted but I think it helps to also “sleep low” to avoid what qquincyjones brings up of stored glycogen. So do a ride, eat low carb after the ride then go to bed and train fasted the next day. You can also eat a high fat bar during your ride if you need help getting through a longer one. This definitely trashes you and would only do it in off season or early season base training and in a limited fashion. I did this a lot last season and became virtually bonk proof, improved aerobic capacity, but was limited in the top end. For sure do not do keto.

Ummm, no. you gotta eat to go long and to recover.

Carbohydrate! You are a Ferrari and even a Ferrari will go slow and stop if you don’t put gas in it.

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