Fasted training

I normally train at 5am riding for 60 to 90 mins generally, I have bike set up in my detached garage, get all my gear lined up night before so it is pretty much a case of rolling out of bed, get changed and I’m on zwift within about 5 mins.

I’ve got into the habit of training fasted just drinking water due to time I train which has worked well for me to get training consistently as allows me to fit it in without impacting family time or having motivation after day at work to ride.

Last food I’ve had is normally about 6pm to 7pm. I do mixture of structured training using erg mode and group rides.

I’ve able to hit numbers generally but must admit vo2 focused workouts are sometimes difficult but aren’t they always?

Just wondering what people’s thoughts are generally about fasted training like this and also what should I eat post workout, at minute I normally have a protein shake that is around 200 cals and 30g protein but wondered what would be best to eat post workout

Personally, I often do much the same, though not quite as quick to get on the bike after getting up. I do think that starting off with protein afterward is a good thing, but you might want to swap out the shakes for some high-protein food, instead. Post-workout carbs can be a reasonable choice, also (though still with some protein), as your muscle cells will be at least somewhat depleted and ready to absorb the sugars to ‘restock’ while not spiking your insulin.

My take, in general, is that - once your body is fat-adapted, training fasted works just fine. A have done a number of 100+ mile rides with only water (which is key, so that your body can process your stored ‘fuel’ into usable energy) and not noted much difference in performance over a carb-fueled ride. (This would be for a training ride or rally event. I would think a race, with the more significant energy demands would certainly benefit from some carb consumption.) You definitely need to make sure that you refuel properly afterward, though.

One other thing you might try is to drink a cup or two of water before you get on the bike (just keep that next to your bed so you can start on it when you wake, since it sounds like you’re pretty quick from bed to bike). This should get your body started a bit faster without creating a need to jump off for a ‘pit stop’ in the middle.

Hi @James_O_Carroll_ARCC

welcome to the forum.

I am doing the same as you and have done it for a long time.

Lately I started experimenting with having some fast carbs before training to see if I can feel a difference having more energy available for hard sessions.

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Keep us posted on the results of this experiment, @Gerrie_Delport_ODZ. Are you also experimenting with timing (e.g. 10 minutes before riding vs 2 hours before riding)? And what sort of carb amounts are you talking about? (Or is this, also, one of the variables?)

You might also look at “The Art and Science of Low Carbohydrate Performance” by Volek and Phinney.


I get up at 5am and on the bike at 5:10am so there is not a lot of time to load carbs.

Currently I am aiming for 30g carbs per hour, when doing hard workouts. For Z2 I’m having less.

Does coffee count? ;-{)

Black coffee: zero calories. That Starbucks “coffee” Donald posted: 2 million calories - mostly sugar! :rofl:

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That’s a meal. Black coffee.

avoid intensity if you’re gonna ride on an empty stomach

  1. you won’t hit your targets
  2. it feels like sh*t
  3. you won’t get faster or lose more weight doing that

just take it easy. if you want to do intervals then eat


Would you please cite your sources for your comments? I train fasted regularly and don’t experience any of the issues you mention. Yes, it requires transitioning to becoming ‘fat adapted’ before you can train as intensely (which can take from a few weeks to a few months, depending on how your body responds), but beyond that I have not had any issues. There are actually a lot of rides where I perform significantly better while riding fasted.


yep - same here.

It does take a bit of getting used to but I have been increasing my FTP with regularity these days*.

*this may say more about my previous FTPs than my current one!


I have never experienced that, hitting targets and feeling bad, never happens even with super hard workouts.

There are many sources saying you should not train fasted when doing hard training. But I have not experienced that, I am testing eating before workouts to see if I improve in performance.

Currently I don’t have any pro’s for or against fasted training. Although I have been doing it for many years.

Sources to papers are in the footnotes and comments. none of them recommend anything over endurance pace when training fasted. though i really think it’s just common sense…

How To Train With Restricted Carbohydrate Availability (RCA) — High North Performance pertaining more directly to this thread

I don’t truly agree with this. If I don’t feel like I need to eat before a hard workout then there is nothing telling me that this is a bad idea.

Training 5am in the morning and eating does not realty work out. Can I hit more PR’s when I am fueled I guess so but once all my PR’s is fueled I will stop hitting PR’s that often. Same with Fasted training.

so my current testing is will I get a lot stronger if I fuel before a workout?

if you’re going anywhere near threshold and certainly if you are going above it at any point in the session then i really recommend it

The same thing as @S_A_Cestria_CC says is also seen in the pro peloton where the focus on lowest possible weight and its okay to go a sleep hungry etc. is slowly falling out of fashion as well. For optimal training all evidence points to fueling being one of the most important factors. The use of Supersapiens might be banned from racing but its still an incredible useful training tool that is used by a lot of the world tour riders to actually insure they are properly fueled.

Fasted training can be good at endurance pace, but your body needs fuel to perform at the optimal level and that applies to before, during and after training

My guess it that a lot of this varies by person, as well as where in the fat-adapted process the person is and what the activity is. Personally, I have no issues performing at my top level in a fasted state. But could I do that for 4, 5, or 6 hours? Probably not. An hour or two is not an issue, though. Plenty of fuel available for that amount of time. And, as Gerrie has mentioned, not only is there not a lot of time prior to riding to eat if you’re trying to train first thing in the morning, but I also don’t want to do a hard effort with a load of food in my gut. I find that I generally don’t want to eat for at least two, and preferably 3, hours before a hard ride.

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I used to train fasted but would generally avoid high intensity sessions. 4x20 at 85% was okay (it had little sprints at the end of the 20min blocks), but something like 9x1 or a 6x3min (at 6.7w/kg) I wouldn’t do fasted.

I also used to do some Zwift sessions in the old days just long hilly rides and doing Epic KOM in mid-19 minutes, I wouldn’t do those fasted either, after 2 hours you end up wrecked.

If you must eat something then a clif bar will do.