Tuesday, 27 May 2014

My quest to become a 'fat adapted' runner

Disclaimer: The following is purely a personal account of my experience of trying to become fat adapted. Please do not take any of the following as nutritional or exercise recommendations.

I have been aware of the paleo or primal diet for some time now. I didn't give it much attention as I believed that, as an endurance athlete (in the loosest sense of the term!), I required a lot of carbs to fuel my training and races. This is a common understanding/misconception. I didn't really see any reason to change and, let's face it, I like cake!

The thing that really changed my thinking on this was an interview with nutritionist Barry Murray on the Marathon Talk podcast. During the interview Barry speaks about the benefits of eating a higher fat / low carbohydrate diet and, in particular, how this way of eating can be beneficial to an endurance athlete. I won't go into the science of it here but if you are interested in the concept of the paleo way of eating and, in particular, how you can become 'fat adapted', I recommend having a listen to the podcast here.

This interview with Barry and also Tom's (one of the Marathon Talk presenters) account of his experience of becoming fat adapted and his subsequent performance at the Manchester Marathon was a complete revelation to me. The timing of this information coincided with my wife (who is not a runner) wanting to lose some weight. We both thought that 'eating paleo' seemed to make a lot of sense, if only for cutting out the processed foods and the amount of sugar we were eating. So, in early April 2014 we started eating paleo. I don't plan to go into what that involves here as there are people that are far more knowledgeable and better able to educate you on the subject. I would recommend visiting the superb Mark's Daily Apple by Mark Sisson as a great resource for everything paleo / primal.

I didn't make these changes to my diet as a means of losing weight (although I was probably a few pounds over what I believed to be a 'good weight' for me). At the beginning of April, I was pretty much bang on 11 stone and my body fat percentage was around 16%, so not exactly heavy for someone of 5' 10" and 39 years old. What appealed to me, was adopting a way of eating that would have long term health benefits and at the same time, allow my body to become more efficient at burning fat as a primary source of fuel during marathon and ultra marathon races.

Inside of 4 weeks my wife and I noticed an increase in energy levels and felt much better generally. I lost about 6 lbs, my wife (who is sedentary) almost a stone. The other thing to remark on was that I was (and still am) really enjoying what I am eating. The food is really tasty and satisfying. I have had a few 'treats' since and haven't stuck too rigidly to the paleo way of eating if I am at a function or having a meal out. I guess I am eating paleo on a 80/20 basis. Interestingly, things like a take-away curry or a chocolate dessert that I used to covert as a treat, really don't hold the same appeal to me anymore and I am someone who has always had a really sweet tooth! As such, I really don't miss the things that I thought I would struggle to give up.

In the last week or so, I have noticed that I am becoming more 'fat adapted'. I am no longer ravenous when I wake up and I am able to go 6 hours quite comfortably without eating. At the weekend, I only had 2 meals each day and I ran 8 miles each day (one run in a fasted state) and played golf once. My total weight loss, since starting in April is 10lbs (current weight: 10 stone 4 lbs) and my body fat is down to 13/14%. I am eating more fat and losing fat /weight. I wouldn't have believed it possible 2 months ago!

Now, I am not in training for any marathon's at present, although I did run the Dukeries Ultra recently. I wasn't sure about my level of fat adaptation at that stage and didn't feel confident enough to completely go low carb/no carb during the race, instead opting for a more 'natural carb' approach to my nutrition. You can read about my experience here.

I will begin training for the Chester Marathon in June. I am hoping by that stage, I will be more fat adapted and better able to tackle the longer training runs on less carbs. Watch this space to find out how I fair in my mission to become a fat burning machine!


  1. Thank you for sharing, I'm interested if you include any sa starches or if you're eating zero carbs?

  2. Hi Aaron, thank you for reading and for taking the time to comment. Your podcasts have been instrumental in me taking these early steps to becoming fat adapted.

    I am eating carbs. Other than vegetables and salad, I am having a small amount of fruit, some white rice and sweet potato. I've not measured it but I would estimate at less than 150g per day.

    Re: speed. I've not really tested my speed but I've got a 5 mile race tonight, which might be a good indicator.

  3. Fantastic David! Sometimes people go too low-carb when switching to a paleo-style diet, but it sounds like you are listening to your body and getting appropriate amounts of carbs