Our last post we discussed carbohydrate (CHO) as a primary fuel source and factors that need to be considered. In this post we want to shed light on an alternative approach to fueling as an endurance athlete and how it stacks up against traditional methods.
With the growing body of literature investigating the current ‘traditional and text book’ endurance based nutrition, I wanted to take sometime to highlight some of the newer evidence along with an alternate strategy. I am not saying this is a strategy for everyone, as in so many areas of our sport (e.g. training and nutrition) there is so much individual variance. However, with my clinical and personal experience if done correctly, I have found an approach that works for the majority of clients and is something I highly suggest you consider and test out, not only from a performance standpoint but for your overall health as well.
Background/ Training Nutrition
Before talking about race nutrition (particularly Ironman) you must first understand training nutrition. The science has made some significant developments in recent years and I want to identify what these recent changes are and then compare them to traditional nutritional methods and try help you identify which is the best approach for you!
What is Traditional/Textbook Endurance Nutrition?
This nutritional method is based around the intake of CHO and the ability to load (before) and continually replenish CHO stores during exercise.
What does this mean?
Typically our bodies can only use ~1g of CHO / kg of Body Weight / Hour. We are constantly told that to perform at a high level or merely ‘last the distance’ in any endurance event requires us to be fueled solely by CHO. Go to any endurance event or even give “Ironman Nutrition” a quick google and you will see this is still a common thought. Ironman itself even puts on a pre-race dinner “Pasta Party” based around this concept, with the intention of CHO loading (I pre-ate before attending).
But sport science is a new science so we are always learning and older practices (nutritional or other) are being re-investigated and newer methods are always being developed and tested. In the case of nutrition for ultra events the science is evolving and initially these challenge all my previous beliefs, creating a lot of confusion (even for me, someone who has studied sport science). But, in taking a step back I was able to analyse from a non-bias standpoint and used a bit of logic to allow me to see the potential of this new nutritional strategy.
So, what was being suggested?
A flipping of the traditional method on it head! Out with the CHO during training and in with the fat! With CHO so ingrained in our culture not only as athletes but also in general day to day life, it can be challenging.
There are plenty of methods that now utilise this approach with some variance within them: High Fat Low Carb (HFLC), Very Low Carb and High Fat (VLCHF), Paleo, Ketogenic, Aktins or Modified Akins. Despite their differences (mainly in their name choice) they all work on a similar premise, that is to reduce CHO used during low- moderate intensity (sparing our very very limited body CHO stores for those rare times when we need to sprint finish) and increasing our efficiency at using fat as a fuel source. Some of the diets listed above are a bit more extreme than others. So which one is best? Again it comes down to you and what suits YOU best.
My goal: My focus is always on efficiency and maximising performance both physical and mental. Therefore, I put the high fat strategy to the test against Ironman, with the intention of be able to utilise fat a primary fuel source throughout the race.
Fat Adapted Athlete or Metabolically flexible
Put simply you have the ability to use fat as a fuel during exercise and this saves your bodies limited CHO stores (~500-600g even when you eat a lot of CHO in your diet). This shift allows you to move away from a limited and finite fuel source to one that is unlimited!!!!!
At the lower exercise intensities required during an Ironman (we are exercising for 8-17 hours) the increased use of our fat stores may mean less frequent refueling and less reliance on external fueling methods (now no stress now if you drop that one gel out on course). Another added benefit of using your fat stores is enhanced fat loss, great for body composition.
Your health is also improved by shifting to a ‘high good fat’ diet. This is due to the fact that when you use fat as a fuel you do not create the inflammatory response that we see with CHO. Less inflammation is great for supporting a healthy body (Let’s talk Science: High Carbohydrate Vs High Fat)
The ‘traditional’ CHO method would argue that fat use in exercise limits your ability to perform at the top end of your chosen sport (endurance and even anaerobic based power athletes). But the recent research has debunked that argument. Some of the best triathletes would consider themselves to be high fat/ low carb and they are winning events at an amateur and professional level.
Put in to practice: Proof is in the pudding
Pro Athletes: It is hard to say exactly who is and who isn’t but those to the best of my knowledge are listed below. Along with being pro athletes a lot of them are also coaches themselves as well.
Simon Cochrane: 1st Rotorua & Karapiro Half Ironman, 3rd place IM Japan, 3rd IM Taiwan, 3rd IM Philippines. IM New Zealand PB 8:21
Jan van Berkel: 1st Ironman Switzerland (in record breaking time), 5th 2018 IM Texas (7.48.40); 4th 2018 IM New Zealand
Tim Reed: 1st 2018 IM 70.3 Vietnam, 2nd 2017 IM 70.3 Asia Pacific Championships, Western Sydney, 2nd IM Australia, Port Macquarie
Dougal Allan: 1st 2018 Motatapu Xterra, 1st 2018 Redbull Defiance, 2nd 2017 IM Western, Australia
Kyle Buckingham: 1st 2018 IM African Championships
Coaches / Athletes: Who are renowned for the High fat approach to training
Bevan Mckinnon (Coaching Service: Fitter): 1st 2016 Kona IM in Age group World Championships
This does not mean it will work for everyone!! I just wanted to highlight that this is a strategy being utilised by top athletes, showing that its does not reduce your performance, in fact it may have the opposite effect. These are just some of the top athletes well known for this approach but there are plenty more and it is a strategy that is continually growing in popularity as science proves the validity of this nutritional strategy in performance and health measures.
How does a Carbohydrate Athlete match up to a Fat Adapted Athlete
I wanted to keep it simple as I know this topic it can become overwhelming to most. Listed below are a comparison of the two strategies.
Key Things to consider:
Below are some key factors to consider before jumping into this approach and often the biggest mistakes I see athletes make.
- CHO Tolerance: Carbohydrate tolerances or insulin sensitivity (ability to produce adequate insulin when required, to ensure efficient uptake of carbohydrate) will vary from person to person. There is no one size fits all macro breakdown there are just guidelines!
- A-Type Personality: The biggest mistake I see especially in the A-Type personality world of triathlon is athletes going to extreme to quick. Just like physical training this shift in fuel substrate should be a gradual adaptation. I highly suggest easing into it, you should never be suffering (eg starving) if so you are pushing your limits too much! However, if done correctly the benefits to your health, performance and longevity will be profound!
- Female Athlete: Females must also be cautious in adapting this approach as you traditionally require more CHO and must consider the impact of your menstrual cycle and design your intake accordingly. For this reason there doesn’t seem to be too many Pro female Ironman athletes currently, I have heard that Melissa Hauschildt (1st Female 2018 IM Texas – North American Championships) is high fat athlete but that has not been confirmed. I think this is something we will see more as we learn how to better cater the approach to the specific demands female body. As quoted by Stacey Sims: “Women are not small men!”
- Train Low Race High: Once fat adapted, athletes to often approach their racing the same as there training void of or minimal CHO. If you want to optimise your performance you buffer your CHO stores so that you can utilise both CHO and fat substrates to their full potential. Although, this has been recently shown to be especially important in more competitive and elite athletes than those working at ;lower intensities
Take home message:
No detrimental effect in performance, less need for refueling, fat loss and faster recovery, it sounds pretty good to me!
I will say it again that as with any nutritional approach there is no one size fits all approach, you must find what works for you! Sometimes that means some long term self experimenting. Take it gradually don’t go all out and end up with Keto Flu.
Burke, L. M., & Hawley, J. A. (2002). Effects of short-term fat adaptation on metabolism and performance of prolonged exercise. Medicine & Science in Sports & Exercise, (2). https://doi.org/10.1249/01.MSS.0000027690.61338.38
Burke, L. M., Wood, C., Pyne, D. B., Telford, D. R., & Saunders, P. U. (2005). Effect of carbohydrate intake on half-marathon performance of well-trained runners. International Journal of Sport Nutrition and Exercise Metabolism, 15(6), 573–589.
Campbell, C., Prince, D., Braun, M., Applegate, E., & Casazza, G. A. (2008). Carbohydrate-supplement form and exercise performance. International Journal of Sport Nutrition and Exercise Metabolism, 18(2), 179–190.
Carey, A. L., Yeo, W. K., Carey, A. L., Burke, L., Spriet, L. L., & Hawley, J. A. (2011). Fat adaptation in well-trained athletes : Effects on cell metabolism REVIEW / SYNTHE Fat adaptation in well-trained athletes : effects on cell metabolism. Applied Physiology Nutrition and Metabolism, (April 2016). https://doi.org/10.1139/H10-089
Cipryan, L., Plews, D. J., Ferretti, A., Maffetone, P. B., & Laursen, P. B. (2018). Effects of a 4-week very low-carbohydrate diet on high-intensity interval training responses. Journal of Sports Science and Medicine, 17(April), 259–267.
Harvey, C. J. C., Schofield, G. M., & Williden, M. (2018). The use of nutritional supplements to induce ketosis and reduce symptoms associated with keto-induction : a narrative review. PeerJ. https://doi.org/10.7717/peerj.4488
Havemann, L., West, S. J., Goedecke, J. H., Macdonald, I. A., Gibson, A. S. C., Noakes, T. D., … Fat, E. V. L. (2018). Fat adaptation followed by carbohydrate loading compromises high-intensity sprint performance. Journal of Applied Physiology, 194–202. https://doi.org/10.1152/japplphysiol.00813.2005.
Jentjens, R. L. P. G., & Jeukendrup, A. E. (2005). High rates of exogenous carbohydrate oxidation from a mixture of glucose and fructose ingested during prolonged cycling exercise. The British Journal of Nutrition, 93(4), 485–492.
Jeukendrup, A. E., & Wallis, G. A. (2005). Measurement of Substrate Oxidation During Exercise by Means of Gas Exchange Measurements. Int J Sports Med, 26(S 1), S28–S37. https://doi.org/10.1055/s-2004-830512
Jeukendrup, A. (2008). Carbohydrate feeding during exercise. European Journal of Sport Science (Vol. 8). https://doi.org/10.1080/17461390801918971
Malatesta, D., Brun, J.-F., Astorino, T. A., Maunder, E., Plews, D. J., & Kilding, A. E. (2018). Contextualising maximal fat oxidation during exercise: determinants and normative values. Frontiers in Physiology, 9(599). https://doi.org/10.3389/fphys.2018.00599
Maunder, E., Kilding, A. E., & Plews, D. J. (2018). Substrate Metabolism During Ironman Triathlon: Different Horses on the Same Courses. Sports Medicine. https://doi.org/10.1007/s40279-018-0938-9
Maunder, E., Plews, D. J., & Kilding, A. E. (2018). Contextualising Maximal Fat Oxidation During Exercise : Determinants and Normative Values. Frontiers in Physiology, 9(May), 1–13. https://doi.org/10.3389/fphys.2018.00599
Newman, J. C., & Verdin, E. (2014). Ketone bodies as signaling metabolites. Trends in Endocrinology & Metabolism, 25(1), 42–52. https://doi.org/10.1016/j.tem.2013.09.002
Oliveira, E. P. De, & Burini, R. C. (2014). Carbohydrate-Dependent, Exercise-Induced Gastrointestinal Distress. Nutrients, 4191–4199. https://doi.org/10.3390/nu6104191
Painelli, V. D. S., Nicastro, H., & Jr, A. H. L. (2010). Carbohydrate mouth rinse : does it improve endurance exercise performance ? Nutrition Journal, 2–5.
Paoli, A., Grimaldi, K., Agostino, D. D., Cenci, L., Moro, T., Bianco, A., & Palma, A. (2012). Ketogenic diet does not affect strength performance in elite artistic gymnasts. Journal of the International Society of Sports Nutrition, 1–9.
Peters, S. J., Amand, T. A. S. T., Howlett, R. A., Heigenhauser, G. J. F., Spriet, L. L., Ln, O., … Lawrence, L. (1998). Human skeletal muscle pyruvate dehydrogenase kinase activity increases after a low-carbohydrate diet. The American Physiological Society, (8).
Peters, S. J., Harris, R. A., Wu, P., Pehleman, T. L., Heigenhauser, G. J. F., Spriet, L. L., … Spriet, L. L. (2018). Human skeletal muscle PDH kinase activity and isoform expression during a 3-day high-fat / low-carbohydrate diet. American Journal of Physiology-Endocrinology and Metabolism, 1, 1151–1158.
Peters, S. J., & Leblanc, P. J. (2004). Nutrition & Metabolism Metabolic aspects of low carbohydrate diets and exercise. Nutrition & Metabolism 2004, 8, 1–8. https://doi.org/10.1186/1743-7075-1-7
Pfeiffer, B., Stellingwerff, T., Hodgson, A. B., Randell, R., Res, P., & Jeukendrup, A. E. (2012). Nutritional Intake and Gastrointestinal Problems during Competitive Endurance Events. Medical Science in Sports and Exercise, (7), 344–351. https://doi.org/10.1249/MSS.0b013e31822dc809
Pfeiffer, B., Stellingwerff, T., Zaltas, E., & Jeukendrup, A. E. (2010). CHO oxidation from a CHO gel compared with a drink during exercise. Medicine and Science in Sports and Exercise, 42(11), 2038–2045. https://doi.org/10.1249/MSS.0b013e3181e0efe6
Prado, E., Roberto, D. O., & Burini, C. (2014). Gastrointestinal Complaints During Exercise : Prevalence , Etiology , and Nutritional Recommendations. Sports Medicine, 44, 79–85. https://doi.org/10.1007/s40279-014-0153-2
Stellingwerff, T., Spriet, L. L., Watt, M. J., Kimber, N. E., Hargreaves, M., Hawley, J. A., … Pdh, D. (2018). Decreased PDH activation and glycogenolysis during exercise following fat adaptation with carbohydrate restoration. American Journal of Physiology-Endocrinology and Metabolism, 380–388. https://doi.org/10.1152/ajpendo.00268.2005.
Stuempfle, K. J., Hoffman, M. D., & Hew-butler, T. (2013). Association of Gastrointestinal Distress in Ultramarathoners with Race Diet Association of Gastrointestinal Distress in Ultramarathoners with Race. International Journal of Sport Nutrition and Exercise Metabolism, 2, 103–109.
Volek, J. S., Freidenreich, D. J., Saenz, C., Kunces, L. J., Creighton, B. C., Bartley, J. M., … Phinney, S. D. (2015). Metabolic characteristics of keto-adapted ultra-endurance runners. Metabolism, 65(3), 100–110. https://doi.org/10.1016/j.metabol.2015.10.028
Volek, J. S., Noakes, T., & Phinney, S. D. (2015). Rethinking fat as a fuel for endurance exercise. European Journal of Sport Science, 15(1), 13–20.
Zinn, C., Wood, M., Williden, M., Chatterton, S., & Maunder, E. (2017). Ketogenic diet benefits body composition and well-being but not performance in a pilot case study of New Zealand endurance athletes. Journal of the International Society of Sports Nutrition, 1–9. https://doi.org/10.1186/s12970-017-0180-0
Zügel, D. (2016). Carbohydrate Intake in Form of Gel Is Associated With Increased Gastrointestinal Distress but Not With Performance Differences Compared With Liquid Carbohydrate Ingestion During Simulated Long-Distance Triathlon. International Journal of Sport Nutrition and Exercise Metabolism.