My second adventure race plus how ‘fat adaptation’ has made me a better endurance athlete

GC adventure race paddle 2My alarm went off at 4:30am… but I think I was already awake. I jumped out of bed ready to go, slightly nervous while quite excited at the same time. My breakfast on race day morning consisted of ½ cup of rolled oats with coconut milk, blueberries, yoghurt, cocoa powder, walnuts, coconut, whey protein powder and honey; far higher in carbohydrates than I typically consume, which I will discuss later. Oh and of course a strong cup of coffee. I am a huge advocate of the performance enhancing abilities of caffeine. My nerves calmed as I ate my breakfast.

Adventure race 1 copyWith fuel out of the way it was time to load up my car in preparation for my second adventure race. Well, technically this was a multisport race as true ‘adventure’ racing involves a navigational component. Although this race would be off the beaten track, the trail run and mountain bike courses were to be marked with tape. The race that I was about to embark on consisted of a 1.5km ocean swim, a 13km ocean and creek paddle, a 12km trail run, a 22km mountain bike and concluded with a 2km run to the finish line. It was the Gold Coast Adventure race, formerly the Anacoda Adventure race. This was a race I had fantasized about participating in for a few years. I contemplated the idea of entering as a team, perhaps with the boyfriend completing the paddle and mountain bike leg while I would do the swim and trail run. I also thought about doing Course 2, which lacked the ocean swim and ocean paddle. But earlier this year I made the decision that I would be completing the full event (Course 1) as an individual.

So back to loading up my small, hatchback Toyota corolla with my 14 foot (approximately 4 meters), 17kg paddle ski, the paddle for the paddle ski, my wetsuit, goggles, swimming cap, mountain bike, helmet, gloves, water pack, running shoes, towel and nutrition for the day. My nutrition took up barely any room as it consisted of one espresso gel and two pieces of a homemade oat and nut slice. This may seem like very little for what would be a race lasting over 6 hours, but I will discuss in more detail later how I am able to fuel my endurance racing by burning my own fat stores.

I packed my car, woke up the boyfriend to say goodbye and headed off for the first transition point to drop off my gear for the run leg. The next stop was the mountain bike transition then it was off to the start line. The race started at Currumbin Alley, the point at which Currumbin Creek meets the Pacific Ocean. Both the swim and the paddle were to commence from this point.

GC adventure race swim startThe weather was not great. There were some clouds looming overhead. It had rained during the night and my thoughts wandered to the mountain bike track, sections of which I imagined would be muddy and slippery. Oh well, there was nothing I could do about that now. The time for the race to begin was drawing closer so I put on my wetsuit and prepared for the race briefing. I noticed that there was only one other woman starting Course 1. I compared my ski to hers and felt somewhat deflated. I had a short, stumpy, plastic ski while hers was a long, slender racing ski. Did I stand a chance to beat her?

GC adventure race swimThe 14 of us participating in Course 1 headed over to the swim start. I felt nervous again. Gary, the awesome race director had earlier grabbed my shoulders and said “Lucy, what are you so worried about? You are here to have fun”. I repeated his words in my mind. What was the worst that could happen? If I lost my ski entering through the creek mouth then I would just have to swim after it; something I had done many times before. And I would just have to take it easy on the steep sections of the mountain bike course given the wet conditions. Everything would be fine I told myself.

GC adventure race paddle startThe swim started and I was pleased to find myself in the middle of the pack. We headed out through the waves around the first buoy. The surf was quite flat that day so the swim did not trouble me at all. I struggled slightly finding the final buoy but managed to get around it and started to make my way in to the shore. I tore off my wetsuit as I ran up the beach to where the skis were waiting. Again I was pleasantly surprised to see that my ski was far from the last one on the shore. But I knew I had the slowest ski so I wasn’t going to be surprised if I was overtaken by the majority of the field.

paddleski waveI paddled my ski out through the waves with no problems. Two guys passed me as we paddled through the ocean towards the creek mouth. I had arranged for the boyfriend to meet me at the mouth of the Tallebudgera Creek to guide me through the paddle in. He was there as promised. The tide was going out so I felt slightly concerned that if I lost my ski it would get washed out to sea. I lined up a small wave to catch in and paddled hard. I rode the wave and as it crashed behind me I tipped out of my ski. I quickly jumped back in and began paddling hard again. I was now in still water. What had I been so worried about?

GC adventure race paddle 3The boyfriend paddled with me for a bit, passing on words of encouragement. I saw that two more guys had passed me on much better skis. It was disappointing but what could I expect. The paddle seemed to take forever. At one point I feared that I had somehow taken a wrong turn in the creek and was off course. I was relieved when I paddled up to the bank and the wonderful volunteers were there to carry my ski up while I headed to the run transition.

I chucked on my shoes, put on my water pack and slammed down my espresso gel. The caffeine hit was just what I needed after the 1.5km swim and 13km paddle. At that point I noticed my water pack had been leaking! There was a tiny dribble of water left which I quickly drank as I began the run. Again, there was nothing I could do about this now. Time to get running.

GC adventure race runThe run course was totally fun. I was running along the creek’s edge; crossing the creek multiple times. I ran over rocks, through thick shrub, under trees, through mud, down hills, up hills; I was having a ball! I passed several people during the run, which made me feel confident. I was sure that I had not seen the only other female competitor doing Course 1. I finished the run feeling strong but slightly thirsty. I asked another one of the fabulous volunteers in the bike transition if she had any water. She kindly poured some into my water pack only for it to start leaking down my back. I jumped on my bike, had a bit to eat and began heading for the first steep climb. Once I reached the top of the first climb the course entered the QLD/NSW border track; a rolling section of fire trails and single track. At this point I drank the last of my remaining water, ate the last of my food and began.

GC adventure race bikeAgain, I found this section of the race fun. I think that is my favourite part of adventure/multisport racing; I was actually having fun while racing. Although triathlon and marathon running do have moments of fun (like when you finish), these races are more about going as fast as you can physically and mentally stand. I am also thoroughly enjoying the training for off road races. Last weekend my training session consisted of mountain biking on some single track surrounded by trees and shrubs, followed by a run on the same track. I was thinking ‘This is great!” I definitely have not had as much structure in my training leading up to this adventure race. I haven’t been focusing on my speed or pace or how many reps in a session. This is very different to when I was training for triathlon or for marathons. I would ensure that just about every training session had a structure and a purpose. Now don’t get me wrong, I am all for structured training. Having a regimented training regime did wonders for my fitness and ability as a multisport racer. But at the moment I am enjoying the freedom of actually really liking my training. If you are a triathlete or road cyclist or a road runner but are seeking a new challenge, I suggest trying some off road races. There are plenty of trail runs, mountain biking events or paddling events to choose from – or a combine all three and do a multisport event!

run 2Back to the race. The mountain bike section went well. I enjoyed it. I only had a couple of minor slips and I felt pretty strong. I came into the final transition to see the wonderful boyfriend with his camera. The final leg was a 2km run to the finish. Due to my background in triathlon I was used to running hard off the bike – so that is what I did. I ran hard to the finish and I was absolutely thrilled not only to finish, but also to find out that I was the first female finisher! My final time was 6:10:52. I was 6th out of the swim but dropped back to 12th after the paddle ski leg. I made up some ground in the run and the bike to finish 10th overall out of a field of 14. My ski leg really let me down and now I want a faster ski. Nevertheless I had a great day and again I suggest that if you are looking for something to new to try give multisport racing and off road triathlon a go.

finish 2Now as I mentioned earlier, I want to talk about my nutrition for the day. I did not feel hungry or fatigued once during the race. Although I will admit that the pace of this race was not as intense as what I am I used to for triathlon or road running, there certainly was bursts of intensity, particularly during the mountain bike. But for a 6 hour+ race I felt good and my energy levels felt consistent. I honestly believe that my low carbohydrate diet, which includes a decent amount of fats is the reason for this. I have always avoided carbohydrates at night since the age of 18, however, last year when I was training for the Gold Coast Marathon I decided that I wanted to really reduce the refined carbohydrates from my diet. At the time I was eating oats and fruit for breakfast and often having fruit at lunch. Also, I had been vegetarian for 10 years and it was at this time that I started to introduce a small amount of meat back into my diet. I immediately lost weight, some of which was likely fluid as a result of reducing carbohydrates. But I have found that a whole food diet that is higher in fat with moderate protein, plenty of vegetables and limited refined carbohydrates and fruit helps me to maintain a healthy weight range. What I am now realizing is that this way of eating has helped me to also become a better endurance athlete as I am able to efficiently burn fat as fuel source and not rely on constant source of carbohydrates. Is this all in my head? No, the science is now showing that ‘fat adaptation’ can increase the rate at which the body oxidizes fat for energy and decreases the rate at which the muscles use glycogen.

Fat adaptation

Fatigue during endurance exercise, defined as a submaximal effort lasting greater than 2 hours, is associated with low muscle glycogen concentrations. Glycogen depletion is a function of the initial or pre-exercise glycogen concentration and its rate of utilization during exercise. Typically, nutritional strategies for endurance exercise focus on ways to increase the amount of available carbohydrates by maximizing carbohydrate storage in the muscles and liver in the days or hours leading up to an event, referred to as ‘carb loading’. In my personal opinion carb loading is completely over used, particularly by amateur athletes competing in events less than 2 hours where glycogen depletion is not actually a problem. An alternative strategy to delay fatigue and improve performance in endurance events is to enhance the ability to oxidise or burn fat as an energy source while reducing the rate of muscle glycogen utilization.

A well-nourished adult can store approximately 500 grams or 2 000 kcal of carbohydrates. Of this, approximately 400 grams are stored as muscle glycogen, 90-110 grams as liver glycogen, and 25 grams circulate in the blood as glucose. In comparison, a lean adult with as little as 7 – 14% body fat, still has over 30 000 kcal of fat reserves. It makes sense to try and tap into this abundant fuel supply. How can this be achieved? ‘Fat adaptation’ is a protocol in which endurance athletes consume a high-fat, low carbohydrate diet for up to 14 days during their normal training schedule (1, 2). Studies have repeatedly shown that fat adaptation strategies drastically increase whole-body rates of fat oxidation during submaximal or steady state exercise (60-70% of VO2 max) in already well-trained athletes, exceeding the rates typically induced by endurance training alone. However, the impact that fat adaptation has on performance has shown variable results (3). This is because high-fat low-carbohydrate diets result in reduced muscle glycogen content, which can lead to fatigue in endurance sporting events (4). The ideal scenario is to follow fat adaptation with a period of carbohydrate restoration. Carbohydrate restoration is achieved by consuming a high-carbohydrate diet and tapering for 1 – 3 days thus restoring muscle glycogen levels in the athlete who now has a higher rate of fat oxidation (5-7).

The proposed mechanisms explaining fat adaptation include increases in fatty acid transporters in the membranes of skeletal muscle cells (8), increases in the activity of the enzyme that transports long-chain fatty acids into the mitochondria, mitochondrial carnitine palmitoyl transferase complex (CPT1) (9, 10), increases in fatty acid availability, increases in the levels of intramuscular fat storage (7) and decreases in the key enzyme controlling the oxidation of carbohydrates (11). Basically fat adaptation makes the muscles more efficient at burning fat as a fuel source and spares the amount of glycogen used; perfect for long, endurance events performed at moderate intensities.

Most studies have investigated short-term fat adaptation protocols, however, I am more interested in long-term fat adaptation. Although for the last 12 years or so I have typically tried to limit carbohydrates to earlier in the day, for the last year and a half I have really reduced my carbohydrate intake and consumed more fat. When I first began this strategy, I found that some training sessions seemed harder than usual. This is also reflected in the research. For example, one study evaluated the perceived exertion of subjects during training before and after a 7-week adaptation to either a fat-rich or carbohydrate-rich diet. Before the adaptation period there was no difference in the perceived exertion. In contrast, after the 7 weeks of diet intervention, training was perceived as more strenuous after the fat-rich diet compared to the carbohydrate-rich diet (12). This higher perceived exertion during training while on a high-fat diet has also been observed in elite-trained subjects (13). The reasons for this higher mental effort needed to sustain training while switching to a lower-carbohydrate diet are not clear, but may be due to altered autonomic nervous system activity resulting in an increased sympathetic and decreased parasympathetic response (12).

For a professional athlete, compromising training sessions could result in missing out on a pay day, however, for a top end amateur athlete such as myself, I have learnt to push through these tough training sessions in a carb depleted state, focusing on the long term benefits. You may also find that higher intensity sessions are mentally more challenging at first when switching to a low-carbohydrate diet, but again over time you can become used to this.

As far as I can tell, there have been no controlled studies investigating the effects of fat adaptation on endurance athletic performance beyond 7 weeks. I predict that long-term studies on fat adaptation will begin to surface as the field of sports nutrition questions the importance of carbohydrates to endurance performance. Professor Timothy Noakes is a sports scientist who is a huge advocate of a low-carbohydrate, high-fat diet, also known as ‘banting’ and has spent years conducting research in this area. I am a huge fan of his work and one of his more recent articles published in the European Journal of Sport Science this year entitled ‘Rethinking fat as a fuel for endurance exercise’ is a great read on this topic (14). Professor Louise Burke is another expert in this field who has published a substantial amount of work on fat adaptation in endurance athletes (4, 5).

Something else that I have always done, even many years ago when I was competing in muay thai, is train on an empty stomach in the morning. Occasionally I will have a very small snack of some nuts or a teaspoon of nut butter, but I am able to train up to 3 hours without eating. I always did this intuitively thinking that this would enhance my endurance (plus I am not hungry at 5am), and now the research supports this. Endurance training in a fasted state, where blood glucose levels are low, stimulates the rate of adipose tissue lipolysis (the break down of fats) (15), stimulates the breakdown of intramyocellular lipids (fats stored within muscle cells) (16) and upregulates the capacity of muscles cells to use fat oxidation for energy production (17). Training in a fasted state is another strategy to enhance your ability to utilize fat as a fuel source, although it can be difficult mentally at first.

run 1So in summary I believe that a long-term low-carbohydrate, high-fat diet combined with fasted training sessions has metabolic benefits for endurance athletes. Following this mode of eating allows your muscles to more efficiently burn fat as a fuel source while reducing the amount of carbohydrates that are utilized, referred to as ‘glycogen sparing’. In races lasting up to 6 hours I have never once ‘bonked’ or ‘hit the wall’ and I need very little calories. In my latest adventure race lasting over 6 hours I consumed one gel after the paddle then ate 2 pieces of oat and nut slice during the run and during the mountain bike. My energy levels felt consistent throughout the entire race. I did consume carbohydrates the night before and at breakfast the morning of the race, which I believe are essential for optimal performance when following a low-carbohydrate diet. Topping up your glycogen stores prior to the race ensures you can get through those bursts of high intensity, such as steep climbs on the mountain bike. While I am not quite following a ‘ketogenic’ diet because I do eat quite a lot of non-starchy vegetables and I enjoy beans, which provide me with some carbohydrates, my diet is pretty low carb. I rarely eat refined carbohydrates, meaning no refined sweeteners or grains, and I limit my fruit intake.

This way of eating may not be suited to all types of athletes, especially those participating in more explosive, intense sports of a short duration. But if you have long term goals for competing in endurance events then I believe that training your body to utilize fat more efficiently as a fuel source can be beneficial to your performance. There are some caveats that go with the transition to a low-carbohydrate, higher-fat diet; firstly your training sessions may seem harder at first and may suffer in the short term, but you will adapt. Secondly fat takes longer to digest than carbohydrates or protein, so I find that I need to wait longer for a high fat meal to digest before training. For this reason, fat is very satisfying and will keep you feeling full far longer than any carbohydrate rich meal. Keep these points in mind when you embark on a low-carbohydrate higher-fat diet. I believe that this way of eating is well suited to endurance athletes. You can find plenty of tasty, nutritious low carb meals on my blog to get you started.

  1. Lambert EV, Speechly DP, Dennis SC, & Noakes TD (1994) Enhanced endurance in trained cyclists during moderate intensity exercise following 2 weeks adaptation to a high fat diet. European journal of applied physiology and occupational physiology 69(4):287-293.
  2. Phinney SD, Bistrian BR, Evans WJ, Gervino E, & Blackburn GL (1983) The human metabolic response to chronic ketosis without caloric restriction: preservation of submaximal exercise capability with reduced carbohydrate oxidation. Metabolism: clinical and experimental 32(8):769-776.
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  7. Yeo WK, et al. (2008) Fat adaptation followed by carbohydrate restoration increases AMPK activity in skeletal muscle from trained humans. Journal of applied physiology 105(5):1519-1526.
  8. Cameron-Smith D, et al. (2003) A short-term, high-fat diet up-regulates lipid metabolism and gene expression in human skeletal muscle. The American journal of clinical nutrition 77(2):313-318.
  9. Fisher EC, et al. (1983) Changes in skeletal muscle metabolism induced by a eucaloric ketogenic diet. Biochemistry of exercise, eds Knuttgen HG, Vogel JA, & Poortmans J (Human Kinetics, Champaign), Vol 3, pp 497-501.
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  11. Peters SJ, St Amand TA, Howlett RA, Heigenhauser GJ, & Spriet LL (1998) Human skeletal muscle pyruvate dehydrogenase kinase activity increases after a low-carbohydrate diet. The American journal of physiology 275(6 Pt 1):E980-986.
  12. Helge JW (2002) Long-term fat diet adaptation effects on performance, training capacity, and fat utilization. Medicine and science in sports and exercise 34(9):1499-1504.
  13. Stepto NK, Martin DT, Fallon KE, & Hawley JA (2001) Metabolic demands of intense aerobic interval training in competitive cyclists. Medicine and science in sports and exercise 33(2):303-310.
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  15. Horowitz JF, Mora-Rodriguez R, Byerley LO, & Coyle EF (1997) Lipolytic suppression following carbohydrate ingestion limits fat oxidation during exercise. The American journal of physiology 273(4 Pt 1):E768-775.
  16. De Bock K, et al. (2005) Exercise in the fasted state facilitates fibre type-specific intramyocellular lipid breakdown and stimulates glycogen resynthesis in humans. The Journal of physiology 564(Pt 2):649-660.
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