A low-carb diet: “I had enough energy throughout the whole race, which never happened before”


Kjell is an experienced marathon runner who has switched to a low-carb diet. But what’s it like running a marathon without loading up on carbs beforehand? Is it impossible or beneficial? Kjell knows:

The email

Earlier this summer I ran Stockholm Marathon for the 17th time. It is almost becoming a routine… But one thing that isn’t a routine is the fact that I’m following the low-carb high-fat diet since last fall.

But what’s it like running a marathon race without feeding on loads of carbs? I’ve heard and read all about it. People say everything from that it’s a great idea to that it’s almost impossible to run that far without carbs. Now I know :-) It works really well! Even better than with carbs.

I improved my time from last year with eight minutes (now 3.35). In all the earlier years, I’ve eaten loads of pasta and bananas prior to marathons, but this year I’ve eaten a minimal amount of carbs and more vegetables, meat, chicken, fish and butter and cream with natural fats instead. This year’s marathon breakfast consisted of scrambled eggs and bacon. And a little bit of sausage :-) Essentially no carbs.

During the race I just drank water. And the running went really well! I had enough energy throughout the whole race, which never happened before when I ate high carb. Then the energy tended to last for 25-27 km (16-17 miles), and then it felt much harder, when the carbs were depleted and my body wasn’t used to using fat as fuel. This year was different. During the second part of the race I passed around 900 people. My guess is that most people I passed towards the end had eaten carbs and were ‘bonking’ :-)

I’ve experienced many great things since I reduced my carb intake significantly: My endurance during long races has improved. I’ve lost weight, 8-9 kg (18-20 lbs) since September. I haven’t had a single cold during spring/early summer, which used to happen all the time before. No pollen allergies! I tend to feel especially sensitive to birch pollen, with symptoms like asthma, itching eyes and a runny nose. This year I haven’t felt that at all. I never become ravenously hungry which used to happen before, usually half an hour before lunch at work.

Today, I’m even more convinced that I’m on the right track when I’ve chosen to eat LCHF.


Kjell, congratulations to your success in the running track and with your health!

Get started

Do you want to try what Kjell has done? Sign up for our free 2-week keto low-carb challenge!

Alternatively, use our free keto low-carb guide, or for maximum simplicity try out our new low-carb meal planner service – it’s free to use for a month.



Do you have a success story you want to share on this blog? Send it (photos appreciated) to andreas@dietdoctor.com, and please let me know if it’s OK to publish your photo and name or if you’d rather remain anonymous.

It would also be greatly appreciated if you shared what you eat in a typical day, whether you fast etc.


The basics of low carb


Do you want to support Diet Doctor and get access to bonus material? Check out our membership.

More success stories

One comment

  1. Pieter
    As an LCHF runner I run all my races up to 50km totally carb free, iow only taking some water. No Cho loading etc whatsoever. 2 eggs for bf and a mug of coffee (Not bullet coffee) for 32km and longer. NO bf even for up to 32km.
    Because of 'unknown' territory at that stage I took 4 half cups of Coke and 2 small bananas on the Comrades ultra (88 km), guess approx 120g carbs in total for the day on the road.

    No bonking no nothing :) (Even much quicker recovery time it seems)

Leave a reply

Reply to comment #0 by

Older posts