What is your Maximal Fat Oxidation Rate?

Photo credit AsiaTri

By Ed Maunder and Dan Plews


Straight off the back of some great racing at this weekend's 70.3 Vietnam Asia-Pacific Champs, we thought it was high time for another blog post. Some epic racing from some of our athletes last week, and greatly deserved. Berks taking second to current back-to-back World Ironman Champ Patrick Lange, and Assad Attimimi and Merle Talviste taking age-group wins (& 2nd spots in the age-group overall).

In the previous two blogs we talked about our paper in Sports Medicine last year where we made estimates of fat and carbohydrate utilisation rates during Ironman Triathlon at different performance standards (8, 9, and 13-h finishing times). We also published the spreadsheet we used to do this online, where individual athletes and practitioners could plug in their own measured values from laboratory assessments to enable more precise estimates.

However, we understand that many individuals do not have access to the...

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Becoming a Low Carb Endurance Athlete - Fat Oxidation and Race Fuelling (Part 2)

Uncategorized Mar 17, 2019

At the end of the last blog we talked about our paper published in the Journal of Sports Medicine. This paper showed that even at very high levels of fat oxidation, some exogenous carbohydrate is required during Ironman racing for professional and top age-group athletes even when fat adapted. However, upon publication, it was unfortunate that it seems the main message received by many was that Ironman triathletes at high-performance levels must ingest carbohydrate in order to meet their energy requirements, or risk bonking. However, this take-home message was incorrect. In fact, a better way to preserve those precious carbohydrate energy stores, through increasing our capacity to make use of fat as an energy source during exercise.

Our ability to make use of fat as an energy source during exercise can and will change with interventions in diet and training. Generally speaking, fitter athletes will have higher fat oxidation rates for a given speed or power output during exercise. For...

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How do I fuel my races with low carb healthy fat? - Fat Oxidation and Race Fuelling (Part 1)

F2wwc6rmr3wzvbdz6jo9 screen shot 2019 03 05 at 3.21.53 pmIt’s Monday, and we’re fresh from some great racing at Ironman New Zealand. It was really great to be down watching some racing again (and yes, I did miss racing myself!).

While down at the event, Prof Grant Schofield and I were invited to present on the low carbohydrate healthy fat (LCHF) performance for Ironman.

The link to the presentation can be found in this closed Facebook group here (anyone can join), and we think it was quite well received with 50+ people attending.

However, as always around racing, one of the main questions we always receive is “how do I fuel my races with LCHF?”. Luckily, along with two of my endurance physiology colleagues at AUT, we discussed this very topic in a paper that used theoretical energy fuel requirements of Ironman triathletes at different performance levels (~8 h, ~9 h, and ~13 h).

This paper was published in the Journal of Sports Medicine, and I’ve tried to summarise below. The science is quite heavy...

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My Training Numbers to 8:24 at Ironman World Champs

It’s been a while! After sharing my training for the 2018 Taupo Ironman, which was well received, I thought it was about time to do the same for the magical day I had in Kona on October 13th, 2018.  

Kona 2018 Ironman World Championships sure was one to remember, winning the age-group race overall and breaking the age-group course record in 8:24:36.   

Descending into the Energy Lab during the marathon. This KM was a 3 min 55 sec. 


I never wrote a detailed race report, however, I wrote a post shortly after the race called Kona Gems and also talked about the race itself on a number of podcasts such as Fitter RadioTriathlon TarenSwim Smooth and Oxygen Addict. At the end of the day, it’s all about the process. So...

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