First fasted half marathon! YEAH!


I’ve been lurking around these threads gleaning gems of information for the last two years, it’s been a fantastic education! I’ve slowly been building up my running mileage again (injured ultra runner here) and I have just completed my first ever fasted half marathon today.

I’d like to report that running fasted I ran stronger AND faster than I have in the past unfasted. And I had a weird moment at mile 8 where something (ketone boost? Gluconeogenisis?) kicked in and I felt absolutely brilliant, it was very odd but GREAT!!

I’m interested to see how my body recovers this week, fingers crossed I don’t have to fall onto the toilet seat or bum shuffle down the stairs :crazy_face:

Have a fantastic week everyone :grinning:


Congrats!!! I like to hear such experiences :slight_smile:
(If I can’t have them due to the fact I can’t bring myself to run regularly :frowning: But I am only 47, it still can happen :wink: )

(Robin) #3

Wow, that’s fantastic!

(Bob M) #4

That is great! Congratulations.


@Alecmcq how goes you? Running the world also. I thought this post by Ali would be along your path.

(Alec) #6

I am AOK! Not posting much, but I promise to get back to it soon. I retired a week ago and am loving it. Still running. Although I have had a couple of injuries in the last 6 months which has set me back a bit. But still going! I hope you are OK and doing well?

I can absolutely believe it, and I have experienced the same. I do all my runs fasted and feel fantastic (when I am not injured!). I always laugh when I hear all the social media runners talking about the importance of gels and carbs and all that rubbish… I shout at the screen: “ALL UNNECESSARY!!! Just get fat adapted, and run on fat!!”

Congrats on the return to running and your excellent HM :clap::clap::clap::fire::fire:

(Doug) #7

Right on, alimc. :slightly_smiling_face:

Former runner here, and that all sounds good. It’s a bit counter-intuitive, but I remember ‘runner’s high’ times where suddenly I felt great after enough distance that it was really surprising.


My baby runs not even can be called running but I can’t imagine eating before. I always do my workouts well-fasted, food lowers my energy and mood to move, carnivore food too. I don’t even like walk right after eating and doing much walking/hiking is only okay when I am well-fasted, again.
But running is more intense than anything I did this far (I mean, if it’s a proper, not super quick run. my intense exercise is always short-living, my cycling has easier times after the cardio parts and I need those…) so I am very interested about other people’s experience about it.
I am not sure I ever will run a marathon but I would like to do half. And eating during any exercise is pretty much out of question for me, it feels very abnormal to me. Of course it’s needed for long things but I never did those and never wanted to. But I never run before fat adaptation and don’t care much about my speed so even if food would have benefits, I still wouldn’t need it for my modest goals.


I’m such a tech idiot I’ve no idea how to reply to people in posts :joy:
Honestly, maybe one of these days I’ll get it!

Thanks guys n gals for all your replies! :grinning:


Hey Alec, congratulations on your retirement. No longer do you have the shield of work stopping you from getting busy. I’m doing OK. I am carrying some work stress in some physical aches and pains, but a low carb, low inflammatory WoE sees me in better shape than work colleagues 2 decades younger.

(Bob M) #12

One way is to copy something from someone and use that to start the post.

Another is to type an “at” symbol and a list of names will pop up. Select the person from there.

I used “Reply” here, but the issue with this is that (at least for me) it’s hard to figure out which post is being replied to.


What was your time in the half-marathon? The body has about 2 hours worth of onboard fuel when exercising. This can vary depending on the intensity of the effort. Both keto and carber have about the same amount of carbs in the muscle at the 45-minute mark (Phinney). This has been confirmed with muscle biopsies. The dreaded bonking can and will occur without food at longer durations and at higher intensities. You will reach a point where the body simply cannot supply enough energy to continue.


@ffskier We came in at 2hrs and 25 mins. It was a trail half, with a fair bit of elevation.

There was no bonk for me at that time, and I was running harder than my usual pace. So we shall see…

I felt stronger at the end than at the start, which was what I was aiming for… I’ve no idea what the surge was at mile 8 but it felt great so I’d like to experience THAT again please :joy:

I’ll def be taking some fuel for longer distances. It’s all an experiment at this point :grinning:


Thank you! I’ve just replied to your comment so hopefully that works. This is why I stay quiet on forums because I feel like such a tech nugget :joy: