I do the same. I can do all workouts, even the VO2 60 minutes fasted. For me this has been a long journey. I am 52 and have to think not only about my performance but also health benefits. Fasted rides are great for keeping your blood sugar in control. This is one of the most important things to do to stay fit and healthy into old age.
If it would be that simple. I do not want sugar to be converted into fat. This gets stored in the liver and is not good. In particular if it is fructose. Also putting on sunblock everywhere and all the time will prevent the production of Vitamin D which is also not good.
Apart from that enjoy life and ride your bike.
Arguably better than cancer though. 
1 Like
This paper recommends doing fasted long sessions.
No thank you ā but, when I would train first thing in the AM, it would always be after not having anything since dinner 7-8 hours before.
Only one researcherās conclusions, but the paper ties fasted training to optimal celluar signaling (PGC1-a, and CA2+)
Baar2014_Article_NutritionAndTheAdaptationToEnd.pdf (913.4 KB)
I have tried fasted for 60 days now.
1,2 or 3 hour rides fasted, well black coffee before the start and one water bottle on the bike. Has worked pretty good for me. intensity varies to burn up to 1800 calories per ride.
I also have changed my menu drastically with less carbs daily and less food volume, too.
Lots of science about this, maybe Iāve found something that works for me.
1 Like
Want to revisit this topic with a question I havenāt found a clear answer to:
hereās the TL;DR : how long to you have to fast before the benefits of a fasted ride can be recognized?
I am implementing some āfastedā rides with the goal of enhancing my base training. I understand there is some evidence that doing a shorter endurance ride fasted can help replicate some of the adaptations made during a longer ride.
I simply donāt have 3-4 hours to do a low intensity base ride during the week, so my protocol has been doing 90 minute Z2 rides during the week, and doing higher volume rides (3-4 hours) on the weekend.
In an attempt to eek out a bit more from the shorter weekday rides, Iāve been doing them upon waking up before ingesting any calories.
But, is this considered āfastedā? I usually eat my last calories around 8pm. I eat a later dinner as my significant other works until 7pm, so thatās just the time we end up finishing dinner. I donāt generally monitor the macros of dinner, so sometimes it can be carb-heavy with something like rice or pasta. Iāll then start training at 7am the next morning, leaving only 11 hours of fasting. Surely Iām not āsleeping lowā, but do I burn enough glycogen during those 11 hours while sleeping to still get the benefits of a fasted ride, or am I likely topped up enough before bed that thereās no difference?
I saw some mention of this in this article, about how fasting overnight will deplete glycogen in the liver, but not necessarily in the muscles, but they said theyāll have a future blog post on it, that I couldnāt find.
Any links or insights anyone can share on this?
Thanks!
I think in the research and amongst coaches āfastedā == glycogen depleted, where to normal people āfastedā == havenāt eaten yet today. I donāt think youāre burning through 1000+ kCal of muscle glycogen overnight and your rides would not be in a glycogen depleted state and you would not get the benefits documented in the research literature. To do a glycogen depleted workout I think you would need a hard workout on day 1, then have a no/low carb dinner or no dinner, then workout the morning of day 2.
My personal opinion is that most people have low hanging fruit that is better to address before looking to do glycogen depleted rides. Maybe if youāre a pro ultra endurance athlete who is looking for those final marginal gains.
On the plus side, I do all my weekday workouts in the early morning (vo2max / threshold / sweet spot intervals, z2, z1) and donāt worry about trying to cram in breakfast and digest it before my workout as Iām topped off from the previous day.
1 Like
thanks for the response. I tend to agree with you on most of what you said, but do have a few comments.
I agree that Iām probably not starting the ride in a fasted state. But, from what Iāve read, the brain is a glycogen hog, so from 8pm-7am Iām probably burning a fair bit. Then, 90 minutes at 60-70% FTP = roughly 1,250kcal for me. Surely, at some point in that ride, whether its at minute 10 or minute 75, Iām depleted of glycogen?
Agree. My goal is performance, and not adequately fueling flies directly in the face of that. Should my workouts ore recovery suffer, this practice would be the first thing that gets abandoned. But, I would argue that if there are additional adaptations available, not eating before a 90 minute endurance ride is relatively low hanging.
Iām curious: Do you make a concerted effort to get yourself topped off the day before, or do you just believe you are? Speaking of low hanging fruitā¦ some carbohydrate before a sweet spot, threshold, or V02 session might make a big difference that you are missing out on.
Iām no expert on this subject by any means but I abandoned fasted training a long time ago, and it seems like the TR Podcast crew arenāt too keen on it these days either.
My understanding is that fasted trainingās main benefit of fat adaptation is more important for long events where it becomes more difficult to fuel. Not so much the logistics of refueling, but the bodyās inability to keep up with depletion.
If 10+ hour days arenāt your cup of tea, youāll probably see greater training benefit just sticking to normal rides and fueling them appropriately. Sugar is high octane fuel - why wean yourself off of it for no good reason?
GCN did a multipart series on keto. I think the conclusion was that it can be done without much detriment, but someone appropriately pointed at that there wasnāt much benefit either. So in the end, whatās your goal?
From what I have seen the brain and some other processes are mostly responsible for the overnight liver glycogen depletion, but I havenāt seen anything that says it impacts muscle glycogen over night. At some point in your endurance ride youāll be glycogen depleted, but youāre not just burning 1250kcal of glycogen at that effort level, youāre burning a bunch of fat. To be really accurate youād need a gas exchange test to see what percentage fat/glycogen you burn at various effort levels and then calculate it out based on an estimate of muscle glycogen. I donāt know if Iām an anomaly but I have done 2hr sweet spot workouts (~1750kJ) within 15min of waking up without problems and occasionally some 2-3hr endurance rides (~1600-2400kJ) where I have a 200cal granola bar while riding and coffee. I donāt know what proportion of those cals is fat/carbs but its not all carbs. I will have a 100cal granola bar as Iām hoping on the bike prior to vo2 workouts, but Iāve also done them without and didnāt notice a difference. I think it is more of a mental thing for those kind of workouts (for me) or maybe it helps with blood sugar due to overnight depletion of liver glycogen.
Iām getting up before 5am and trying to be starting at 5am so I can ride for 2 hours and be cleaned up and ready to work at 8am. I have no desire to get up 1-2hrs before to have a proper breakfast prior to working out. Since I ride early I have plenty of time during the day to eat and replenish what I burned during the morning workout. I donāt do anything special, just make sure I have a well balanced diet and get plenty of carbs in during the day and at dinner. I track calories and am 55-60% carbs so I think Iām refueling appropriately even if Iām running a small deficit.
My understanding, from what Iāve read, is that if you want to improve āfat adaptionā you would want to do 1-2 depleted endurance rides during a week. These place a lot of stress on the body (from the initial glycogen depletion workout, the lack of recovery during the 10-12 hrs between workouts, and the second workout in a depleted state.) My personal opinion is that the risk is not worth the reward for most people to go through that.
1 Like
fyi
1 Like
Because, in many circumstances, itās either not needed, or even detrimental to aims of a particular session (e.g., increased signaling/mitochondrial biogenesis).
John Hawley has published some excellent work on the subject.
1 Like
Fantastic. Thanks for sharing this.
Most important quote from that podcast, IMO: āā¦ make sure you are actually depleting the tissue you are trying to stress. If you want to stress skeletal muscleā¦ an overnight fast and running without breakfast just wonāt do itā
I think @Craig_G said it in another way:
Fasted doesnāt equal depleted. I may think Iām getting an additional benefit from not eating before my morning endurance ride, but Iām just stressing my liver, not my muscles.
I think Iāll have my Ezekiel bread and jam before tomorrowās ride.
I was aiming to get PB on my local TT on March, ( best time around 34 minutes on 2017 , after that I was plateau until 2019 because too much intensity on every rides ).
I did structured training since last year ( polarized ), mainly only using HR as measurement.
Even though I donāt want to lose weight ( in fact I tried to gain weight from muscle ), I do fasted ride on endurance ride ( 2 - 2.5hr ) without even drinking. On the long ride ( 4hr ) I fasted until reaching half time and then refueling through the remaining time. Iāve still not really sure though if I done it right or not, But I felt the benefit when I do long ride ( 6hr with 1.45hr climb ) with proper fueling.
How do you thinkā¦
My opinion is not drinking for 2 - 2.5 hours does not sound good. Fasting is about fueling not dehydration.
Most guidance Iāve seen on ārealā fasted riding (i.e. glycogen depleted not just didnāt have breakfast) is to keep it short, like 60-90min. If going longer start eating after 60-90min and through the end of the ride. And 1-2 times a week max and carb up after the ride.
3 Likes
I see, thanks a lot.
Your comment is Screenshot material for me.
I did that because not only Glycogen issue, I often had hydration issue as well( I usually drank every ~ 30mnt ), so I came with that idea.
On 2 , 2.5hr rides I feel okay,
But on 4hr ride, I really struggle on the last hour.
Not only HR drift from around 145 to ~ 160 ( HR max 200) , my legs felt empty too
That depends on your overall constitution. I have to follow a relatively low carb nutrituon. And without much of long term carb input the basis for 1-3 hours of training is simply not there if the workout touches into higher effort levels. I would not make it through the sessions without short term high sugar intake right before or during the training.
If the 1-3h session is āonlyā Z2 then it might work for me, but I always have sugar with me.
1 Like
Today Iāve tried my first outdoor fasted ride. 5h total, first 1.5h fasted. I dont know if its optimus to start taking carbs halfway of the ride, but I was feeling able to spend more time fasted at z2 pace.
Yesterday I did a 2h easy indoor workout, lunch was low on carbs, for dinner I took some fat and protein too, but Iām no sure if my glyco stores were really depleted. Should have I incorporate some intensity the day/s before to burn carbs? Or slow ride plus little or no carb intake is enough?
I wouldnāt do fasted/low rides with a time budget that allows for 5h rides. And with 5h - even at low intensity - you get into the low glycogen status with eating (plenty) of carbs. Just my opinion though. I consider this only as tool for the very time starved or for long hair, bearded ultrarunners.
3 Likes