Stephen Seiler chats with Kilian Jornet

Not cycling specific, but fascinating insight in to possibly the world’s best endurance athlete. Just grabbing some popcorn for the comments on the fuelling section.


Saw that posted on Monday, haven’t had a chance to view yet.

I did read this:

don’t recall seeing any popcorn worthy fueling comments. Guess I need to listen.

On a related note, Seiler tweeted this before the interview:

something I found to be true as well.


I think it was mainly the no water/food during training for 4h training sessions.

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I’ve tried a couple of weeks fueling 2 hour rides at 90g/hour. There are a lot of 180-200W endurance rides, about 1300kJ work in total, and so far my conclusion is there are no advantages to pouring sugar water down my gullet.

I’d rather time my before/after fueling and eat real food. I’m also getting tired of the post-ride cleaning sugar water off the bike frame.

Yesterday went back to finishing lunch about 90 minutes before, and on the bike ate 300 calories (Blueberry almond Cliff Bar). Two bottles of water. No issues, just like in the past,

I’m ready to go back to only drinking calories on longer rides, starting around 2.5 hours and longer.

My gut has zero issues with 90g/hour in a bottle. But my metabolism doesn’t appear to like it - I cut back on food and still watching my weight slowly rise the last 2 weeks. Yeah its only been 2 weeks, but consuming 30-50% of kJ burned has worked really well for me over the years.

Maybe I’d be singing a different tune if I had a 350 or 400 watt ftp, and was doing 7-12 hour weeks. But mine is around 270W.


Same, for under 2 hour rides at endurance pace just water is fine or under 90g total. I do this even after an overnight fasts regularly due to time constraints with my long commute. I still like carbs for shorter intense efforts but this idea that all rides need 90+g/hr hasn’t seem to match up with my own experience


It was a treat to hear his comments about HIS training and HIS nutrition. Met him a few years ago, such a humble dude.

Key to his comments is that we are all unique and what works for one, doesn’t necessarily work for another person, but play around with training and nutrition to see what works best for you. All about perception, which he goes into.

Worthwhile to listen to this several times to catch the emphasis on key points instead of making our own prior conclusions. Trying to listen with a virgin ear. Remove the bias from what I have been fed previously.


Haven’t watched yet, but Kilian is famous for not eating. Years ago I saw some video of his where he was headed out for an effort that he expected to take maybe 18 hours, and someone asked what he was bringing for food and he said “one Snickers… well, it will be a long day, maybe two.”

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Same here. Happy to see others who don’t subscribe to the “Slam sugar all the time” writing about their training experiences.

Kilian strikes me as the kind of athlete who is just so darn good that anything works. Am never certain what is applicable to my world based on his but enjoy the stories. Amazing athlete and accomplishments.


Actually just listened to That Triathlon Show interview Dr. Poglacar (beloved by TR ) basically stating for average athletes (ie us) under 3 hours to consume way less than the 90+ g/hr. The Pros he works with are eating way more. Seems to line up with your experience. I am doing about 40 g at most per hour and doing great on my training rides…note also trying to lose necessary weight.


@WindWarrior completely agree. No need for that much fuel on shorter (endurance) rides is my expierence as well.

Wrote this in pro/elite thread where this video was also posted

‘‘16:50 - 18:45 was interesting to hear. I’ve been interested in fasted/low carb training again lately even though a few years back I thought I would never do it again. Ofc it’s important for ultra etc. But the health argument about metabolic flexibiliy is what i mean’’

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Agree with tailoring carbs to the length and intensity of the ride. I fuel the long rides and the hard rides well, but anything of 2 hours or less that’s mostly Z2 I don’t find it necessary.

I do also think though that there are a lot of differences between riding and running that would drive a different approach even at the top level. One is that eating and absorbing a lot of carbs is much harder when running than cycling due to the up and down motion. Second is that there is a higher cost of having to carry a lot of nutrition when you don’t have a bike to hang it on. Third is that running tends to be a very steady intensity as there’s no draft benefit, not much in the way of tactics, and even running downhill requires quite a lot of work. So if you’re doing a long running race you will likely do the entirety of it in a zone where you’re burning a high % of fat and eking out your glycogen stores. Whereas in an equivalent length bike race, even if it’s solo the fact that you’re getting a total break on descents means it’s better strategy to push higher intensity on the climbs which uses up more carbs. And if it’s a road race where you’re in the bunch then attacking or responding to attacks, your effort is going to need be much more polarised with a lot of high intensity necessitating a lot of carbs to fuel it. I don’t think the approach that Jornet describes would be optimal for any cycling event.


I say do what feels best for you. Personally, I find that a 2 hour middle to upper zone 2 ride is not a trivial ride. Averaging 220 for 2 hours feels better to me when I have fuel. It may not be necessary, but how it feels is important to me. Now most of the time I’m riding straight out of bed, so perhaps that fuel just wakes me up, but even when I’m riding later in the day it seems to help. I mean that is 1500 calories or more burned. Now maybe this is more noticeable inside rather than outside because the lack of other stimulus to distract you from the fact that you are getting hungry or feeling depleted, but either way, I prefer to eat. Also not saying I need 90 grams or anything like that, but 40, 50, 60 or something seems to help


The other thing I’ll ask here although may be a different rabbit hole, but do folks think that he’s burning fat instead or that his glycogen stores just sustain longer than we expect, or maybe a mixture of both that allows his glycogen to stretch further. This is obviously not a question about short rides as glycogen will sustain those whether optimal or not.

I was coincidentally watching GTN video of a no food ironman experiment. They said that a normal person that hasn’t trained fat adaptation could burn 1 gram of fat per minute and that a well trained person could do up to 1.5 grams of fat per minute. With the assumption that 1 gram of fat = 9 calories (which I believe is correct), that equates to about 540 calories from fat an hour up to 810 calories. If you subtract basic body functions, maybe 70-80 cals per hour, that wouldn’t get me very far. On the low end 470 cals of energy. If 200 watts is roughly 730 calories or something like that, then I’d only be able to push 130 watts if I was running off of fat only. If I was well adapted I might could push into Z2 at close to 200 watts. Now maybe the answer is, even on a 4 hour ride, you may not be ever running off of fat only, but the guy in the video sure did bonk hard.

This paper:

has some interesting charts comparing fat oxidation rates between moderately active (exercise a minimum of 3x per week and 150+min) and world class cyclists:

yes, elites have high fat oxidation rates.

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He has been doing a lot of high altitude stuff in recent years. When you’re talking about 8000m ascents, long efforts with almost no nutrition are pretty much a requirement, and he is far from alone in this. There is barely any digestion at that altitude. The body is barely just staying alive.

Coming from the running world, I was always puzzled by how much cyclists eat. I used to race marathons on 3-4 packets of gu and never bonked. It was always explained to me that when you’re going just below threshold for 2.5-3 hours straight, digestion slows down to a point where anything more than that will just slosh around in your stomach. The jostling doesn’t help either. A packet every 30-40 minutes was pushing my GI limits.

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Listening now, and around 14 minutes in he stated that his body is highly fat adapted.

Everyone is different. My ftp is around 270. My typical rides are around 2 hours. Endurance rides are 1200+ kJ. Yesterday I did 2 hours with a 1x30 minutes a little over 90% ftp, about 1600kJ, and no problems fueling with only 600 calories and then dinner an hour later. I’m a bigger guy at 90+kg and 185cm, seem to have good on-board storage for my ftp, and decent fat burning.

I don’t need any gut training to do 90g/hour or 100g/hour. Haven’t tried 120g/hour.

Fueling should be personalized, we aren’t robots. Everyone is different.

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My understanding from the vid is hes only fasting on relatively shorter runs(<4 hours) and still using carbs for races. So think its a combo of higher fat oxidation with some glycogen utilization along with increased mechanical efficiency

He was on Sonyal Looney’s podcast a month ago, haven’t listened to it yet but i find him to be a good listen. Maybe its the southern accent based in Norway

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I have been struggling with this as well and also find if I time my off the bikes meal right I do not need much fuel for 2hr endurance work either. Lately I have been brining fig newtons and just water. Two are 20g/cho and if I do get hungry they seem to hit the spot. Fueling with real or semi-real food (processed) seem to work better for me vs just straight sugar. I have fueled with 60-90g/carbs of just sugar water (Gatorade mix) and then even craved sugar later in the day. It is a hard balance and from a longevity point of view, it doesn’t make sense pounding sugar is the right way to go even though your body might need it.