A few questions about fasting rides (fasted training)

What podcast is that?

It was one of the episodes of “The Cycling Podcast” Unfortunately it was on one of the segments where the guy from SIS answers listeners questions in one of the bits reserved for the programmes sponsors and does not appear in the description of the episode so I don’t know which one.

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I do all my rides fasted. Even the 60 minutes V02 ones.

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This is my understanding of one of the few valid reasons for BCCA supplementation, leucine being the main component.

Rather than for muscle synthesis itself It’s role used in this way is to spare muscle damage while training in a fasted state, the theory being that taking the BCCA’s before a workout allows the body to remain in a fasted state but still offer that muscle sparing capability.

I haven’t used BCCA’s for a long time but when I did I used the 4:1:1 ratio of leucine, isoleucine and valine rather than the 2:1:1 variety for that reason but whether I was using an effective dose according to this I can’t remember.

Fasted is one thing. (No food intake in the near past, maybe 8 hours or so as a rule, but still has glycogen in the muscles?)

Depleted is another. (No food intake AND depleted glycogen stores from the muscles via hard efforts before with no refueling after?)

I am sure I haven’t probably covered this totally accurately, but I think it captures the essential difference.

Interesting idea, to clarify though it would seem to be crucial to ingesting BCAA’s that contain zero (0) sugar. Coach Chad mentions in this article that ingesting anything before a fasted ride besides caffeine will make the fasting ride pointless.

“Even though there’s not a ton of sugar in something like half and half or low-sugar coffee creamers, there’s still some, which will disrupt the entire fasting process if you consume it. Why? Because you’ve just introduced glycogen into the mix.”

Most BCAA’s have a lot of sugar (either fake or real), so you would have to go the sugarless route…

Interesting discussion on BCAA’s can be found here too

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I can’t believe" your fat metabolism shuts" down with the merest hint of carbs. If that were the case every time you went for ride and had any carbs you would not be burning any fat, which is absurd. I have assumed people say NONE to avoid the question “How little is a little?”


Yup. You would have to use unadulterated BCCA powder which is pretty grim stuff on it’s own as I well know!!

Again from my reading this is possible as while the absolute fast is broken the amount is minimal enough that insulin levels are raised but not significantly spiked as they might be from eating other food sources.

I guess one other point might be while you are breaking the fast it is broken by calories from protein rather than fat or CHO, so not a preferred energy source for the body, still allowing the body to tap more into fat sources for fuel during those ‘fasted’ workouts. This is just inference on my part though, I’ve not seen any research that supports it.

It all might still be snake oil though!!

Check out info from an elite cyclist & sports dietitian! http://www.thecadencekitchen.com/

There are better ways to boost performance and lose than to suffer through a fasted long ride. Try an overnight fast, time restricted eating, but do not starve the actual ride. This is when your body is most primed to effectively use calories.

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Didn’t want to create a new thread to ask this; do people find when they do fasted rides in the morning, even recovery such as pettit, that they sweat more? Or is this just me?

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Hmm…interesting question. I try to do 1-2 fasted endurance rides a week but I’ve not taken notice of the amount I sweat during those rides as I generally just sweat a lot any time I’m riding. I certainly haven’t noticed anything significant.

I don’t sweat more, but I have notably higher HR and RPE when fasted


I just listened to the TR Podcast on intermittent fasting and had to comment. I love the pod and the info they have is fantastic. But they’re giving poor advice on fasting and fasted rides which is unfortunate b/c the solution, according to the pod, is a gel before the ride, a gel 20 minutes in… and keeping sugar high will make everything easier. That is so much sugar! Sugar, even if you’re burning it, is so bad for you! Even elite athletes burn out on sugar or get diabetes (see Dr. Timothy Noakes). There is another way! Yes, jumping into a fast or a fasted ride would be difficult and not work well but you can totally make your body fat adapted. Becoming fat adopted takes about 2 weeks to start and maybe 6 months to optimize, but it’s worth it (and faster for athletes btw). Read “The Art & Science of Low Carbohydrate Performance” by Volek & Phinney. Such a healthier lifestyle! And no more gels, sugar water, etc… Just my two cents and I’m happy to share my experience with anyone if there’s interest. Last note… I routinely do my sweet spot rides and 3-5 hour mountain bike rides on an empty stomach and with zero calories. And I’m not special. Just fat adapted, which we all capable of.


@Djf500 To become fat adopted in that timeframe (2 weeks to 6 months), did you do this every time you got on the bike? Even if the workout called for VO2 Max intervals?

Absolutely. The 1st couple of weeks of LCHF (low carb, high fat), while your body is learning to run on fat instead of just sugar (carbs) are a little rough. Your energy may dip during your daily activities and you’ll feel it on the bike during hard intensities. There’s little tricks, like drinking water just before you ride and adding electrolytes to your water (not sugar… just minerals… there’s several good products out there). I learned a lot from the book I mentioned.
Winter or off-season is a great time to do this. I switched in the middle of the riding season which wasn’t super smart :slight_smile: Ideally, I’d time the dietary switch with some down time or at the very least, sweet spot 1. Exercise will help you adapt quicker but don’t get discouraged if you dip in efficiency at 1st it’ll come back. The longer you go, the more fat adapted you’ll be. You can absolutely do VO2 Max intervals after a few weeks. There’s tons of videos and podcasts about keto. Youtube has a ton of free info and the book “The Art & Science of Low Carbohydrate Performance” is an easy read and invaluable resource since they’re really talking about endurance athletes… so it speaks directly to what we do. And they have the science to back it up. Ultimately, once you can run on fat, you’ll be ‘Dual Fuel’ where you can run/bike on fat for hours and you’ll still have your sugar burning system of course so if you do take a gel… it’ll be like rocket fuel! I haven’t had a gel in about a year probably… but I don’t race. I could see it coming in handy for the last push in a race or something like that. Or even just to use as you fat adapt if you’re really struggling. It’s been an awesome journey for me. So much healthier w/o sugar, cheaper (sorry Hammer Nutrition… don’t need you anymore) and I can ride without eating/crashing/eating/crashing. It’s a life style change but very worthwhile for those willing to put the work in.


Here is my opinion on this.
Maybe at the elite and pro level it may be useful but for the rest of us it is junk. The questionable benefits if there are any, are negligible. The 1% benefit you may gain, you will definitely lose on the course because of simple mistakes (equipment choice, wrinkles, getting out of aero 10s too much, fueling, etc). I put it in the category of altitude training. If you ever get to the point of needing it to win, do it. Otherwise listen to the pros who eat a hearty breakfast and then go ride.


I realise to am replying to this months later.

As I understand it, the presence of carbs/plentiful glycogen don’t shut down fat metabolism during exercise, but they inhibit the mitochondrial synthesis that is observed after fasted/depleted training.

If one of the goals of the training session is increased mitochondrial density then fasted/depleted training could be beneficial.

On the other hand, I might have completely misunderstood.

@Djf500 Is there a scientific way to empirically measure fat adaptedness? (besides your N=1 comment. I don’t mean this as a criticism. Genuinely curious.

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I agree. All that sugar over 20+ years riding is not good! As usual, there’s a big middle area between sugar all the time, and full Keto. You can absolutely become less reliant on sugar without going full Keto/fully “fat adapted”. The link in one of the posts above offers suggestions.

Yes - or at least, fat vs carb use during exercise can be measured. The standard way is through an RER test. I’ve seen some people post results of their tests on this forum, but I can’t find the post. It was very interesting. Showed a lot lower fat betabolism in the year the person had been on a carb heavy diet (if I recall).


Found it. This post highlights why for long rides you need to have robust fat metabolism. Awesome post by the way - thanks @konradkowara for sharing.

I love the TR product and podcast, but this is something I think the TR crew have not given enough credence to. A sugar and carb approach is great for 1-2 hour rides, and absolutely should carb load and eat during long rides, but to make it through long rides, you need robust fat metabolism. And the ways to train this don’t always align with just getting the highest FTP.

Take a look at the 2017 vs 2018 fat vs carb profiles for the person who posted this. It’s very telling. Imagine trying to do the LT100 with a profile like the 2018 one.