ultrarunning nutrition

Key Takeaways from International Society of Sports Nutrition Position Stand on Ultrarunning Nutrition

By Jason Koop,
Head Coach of CTS Ultrarunning

In September of this year, the International Society of Sports Nutrition came out with a new position paper titled “Nutritional considerations for single-stage ultra-marathon training and racing”. You can view the whole paper, in its entirety, for free here. It’s about a 40 minute read and moderately digestible (starting off with the puns early) for any audience. If you want any further detail, I encourage you to check it out in the paper’s entirety.

Before we dive into the highlights of the position paper itself, I want to take a few lines of the blog to explain why these papers are important, and why athletes should pay attention. The research landscape is enormous, far too vast for a reasonable person to consume. All too often, coaches and other practitioners who work with athletes disseminate articles they come across on Twitter, Instagram and YouTube. This way of information dissemination, in many cases, create a very insular view of the landscape (you only follow who you choose, and the channel’s algorithms are tuned to serve you more of what you like).  Personally, it has been an effort to make sure that I am receiving a balanced perspective of the sports science landscape.

On the nutrition front, I follow RDs and nutritionists who work in team sports, combat sports, and the speed and power sports as well as endurance sports. Some of them laude ketogenic and low carb diets (and you know where I stand on that). I follow vegans, carnivores, whole-foodies and everyone in between. Position papers like the one I’m talking about this week generally do an excellent job of researching all aspects of a particular topic and then presenting a consensus of the literature. They do this by leveraging many people (there are over 25 authors listed in this paper) and many individual papers (nearly 200).

Furthermore, it would take me as an individual around 300 hours to consume and understand all of the referenced material, which is far more time than I have available. Yes, there is no substitute for reading and knowing all of the background literature. I try to get my eyeballs on as much as I can, and still I will fall short. The landscape is so vast, that it is impossible for a coach or athlete to consume it all. These papers take a lot of the leg work out of the process.

That being said, let’s dive right in! I am going to split the next two blogs reviewing this position paper. First off will be some general thoughts (which you won’t want to miss) as well as nutrition for training. Next week’s blog will focus on nutrition for racing and supplements.

Ultrarunners are getting it wrong

If you are trying to cheat by just reading the abstract or the highlights, you are missing out. Here’s something you won’t see in the highlights: ultrarunners are getting their nutrition wrong, and they get advice from unreliable sources. While the authors don’t take a deliberate position on this particular aspect, if you take a closer look, you will catch their drift. Riddled throughout the position paper are cheeky lines such as:

 ‘(Ultrarunners) tend to favour the insights of other athletes over qualified professionals’

And my personal favorite-

‘Despite the importance of sports nutrition for ultra-marathon training and racing, athletes and coaches face a number of obstacles including (sic)… poor education (of Coach/athlete/support staff).’

So in addition to the arduousness of training for ultramarathon events and the actual events themselves, complete with all of the associated trials and tribulations, athletes also have to overcome the terrible advice from the people who are trying to help them; their coaches, fellow athletes and support team.


But I actually agree. One needs to look no further than former Western States Medical Director Marty Hoffman’s 2011 research, which asked the simple question, “What were the main problems that impacted your race performance?” Athletes routinely answered that question with the usual cast of characters: Blisters, nausea (which is relevant to this topic) muscle pain, exhaustion, etc. Only 13% of finisher and 15% of non-finishers listed ‘Inadequately trained’ as one of the problems that impacted race performance. Since that study was released, my contention has always been that if you have blisters, nausea, muscle pain and are exhausted, you are also inadequately trained. All of the runners who listed those factors as impacting their performance should also say that they are inadequately trained, as those aspects are all trainable. The fact that they do not only reinforces the authors’ positions that ultrarunners still have a lot to learn. Coaches, athletes and support personnel can and must do better! The information is right in front of us, we just have to listen.

Recommendations for training

Matching energy demands is challenging

The authors state that “The foremost nutritional challenge (emphasis mine) facing the ultramarathon runner is meeting the daily caloric demands necessary to optimize recovery and permit prolonged and repeated training sessions.” Simply put, eating enough calories is your biggest challenge. It’s not so simple in practice though. Due to training demands, caloric requirements can easily double (or even triple) on a long run day as compared to an easy run day. While the authors compare one hour runs to three hour runs to demonstrate this point in the chart below, it is relatively easy to extrapolate from there.

Double the energy output means double the amount of foodstuffs an athlete will need to take in to perform the simple task of eating enough calories. Sometimes that volume can be overwhelming, and athletes just don’t feel like eating that 3rd apple or 4th slice of pizza. My recommendation, on big training days (>3 hours), is to keep your caloric deficit to a minimum during the training session itself (more on that next week) as well as to consume 20 g of protein every 3 waking hours, which is a suggestion the authors describe later in the paper. Also, athletes would be well advised to beef up their portions for any standard meal on any longer run days. If you are still short on calories from a heavy training day, make it up on a rest/recovery day. Bottom line, don’t skimp on the calories, particularly when the training demands are high.

You still need a high carbohydrate diet

Despite low-carb, high fat and ketogenic strategies continuing to make the nutrition and social media rounds, the authors still come to the conclusion that ultramarathoners should consume a diet consisting of 60% carbohydrate, 15% protein and 25% fat. I agree with this and allow the caveat that when the training intensity is very high (like during a RunningInterval phase) the percentage of carbohydrate can go up 5-10% from there, and when the training intensity is lower (recovery days or EnduranceRun days) the percentage of carbohydrate can go down 5-10%.

Specifically relating to a ketogenic diet, while the authors concede that there is a ‘degree of benefit’. They go on to state, “Ketogenic diets have been associated with acute negative symptoms, including; fatigue, headaches, poor concentration, lethargy, GI discomfort, nausea and weight loss.” It almost sound like a legal disclaimer for a prescription drug advertisement if you read it fast enough. Furthermore, the authors point out a little caveat of keto adaptation that I had not previously considered. Athletes who are not fully keto-adapted, and are still training, are doing so in a chronic glycogen depleted state. This forces the ultrarunner to be ‘acutely catabolic’.  Meaning, there’s all the breakdown and none of the building back up.

Still not dissuaded from partaking in a ketogenic diet? The authors go on to elucidate that significant increases in fat intake are also associated with poor intake of fiber and micronutrients such as iron, magnesium, potassium, folate and antioxidants, all of which are essential for health and performance.

I’m going to end it there.

‘Train low, compete high’ can be valuable, but has consequences

The authors state that, “Nutrition strategies that promote or optimize fat oxidation should be prioritized.” This means that specific training sessions completed with reduced carbohydrate availability (‘train low’) may be of some utility. This utility comes from the body’s ability to utilize fat more and carbohydrate less at any given intensity. The runner can therefore rely less on exogenous carbohydrate as prolonged intake is associated with GI distress. The two most common, and in my opinion feasible, ways to do this are:

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  • Fasted morning endurance session. If you are going out on a normal EnduranceRun you can do so before breakfast in a fasted state.

In most cases, there’s no harm to this as long as the run is <2.5 hours and kept at a lower intensity. If you plan to do intervals or any high intensity work, get some calories in beforehand so that you can optimize the session.

  • Training twice a day every other day

I’m honestly not as thrilled with this strategy. It’s logistically complicated, results in a lot of junk miles and the metabolic adaptations are prioritized over volume considerations (i.e. you are doing a second session not because you need the miles, but because you are trying to induce some sort of metabolic shift). Yeah, this strategy works at promoting fat oxidation, but if I put my coaching hat on, I think there are bigger fish to fry (staying healthy).

I do appreciate the paper’s pragmatic approach to the potential consequences of undertaking any of these fat oxidation strategies. All too often, when we are looking at one or two scientific studies, we fail to see the forest through the trees. This has been the case with some of the ‘train-low’ strategies researched. Sure, if you undertake the exact protocol used in the research design you might get some metabolic advantage. But, sometimes those types of session are not practical, or they prioritize the fat burning adaptation over what you would get with higher quality session. My advice? Read on….

Gut training

While the paper does not discuss training the gut much and does so primarily (and ironically) in the racing section, I feel this is a good point to interject some of this recent research in this area. Another way to alleviate the GI distress associated with taking in the foodstuffs necessary to fuel an ultra is to ‘train the gut’. By fueling specific sessions at a rate above what you think you can sustain during a race, the gut can adapt and improve much like the rest of your body adapts and improves to running more, harder and faster (Costa 2017, Cox et al 2010, Jeukendrup 2017). For example, if you plan to take in 250 cal/hour during your next race, you should pick key training sessions (>3 hours) and fuel at a rate 10-30% above that amount. Or, you can simply train by consuming 90 g CHO/hour using multiple transportable carbohydrates (which a combination of most gels, chews and drinks will contain) which will be well beyond what most ultrarunners will consume during a race. Conversely, a poor strategy would be to consume 200 cal/hour during your long runs and then think that magically your GI system will be able to handle 250 cal/hour on race day.

Once again putting my coaching hat on, I prefer these ‘training the gut’ strategies over the ‘train-low’ strategies to avoid GI distress, as they have fewer downsides and are generally less problematic.

Daily hydration: keep it simple

Leaving the simplest thing last, athletes can monitor their daily hydration status with a combination of the WUT self assessment (below) and by weighing before and after activity. WUT stands for weight, urine and thirst and athletes can monitor this upon waking. If two or more of these markers of dehydration are present (you weight is down, your urine is dark or you are thirsty), you are likely dehydrated. Post exercise rehydration (from both food and fluid sources) should be 150% of the fluid loss and contain 460 mg/Na/L coming from all sources. Practically speaking, this means that your post run beverage should contain some amounts of sodium, or you should get that sodium through your post run meal.

Figure 1- WUT diagram (Cheuvront and Sawka 2005)


And there you have it! All of your daily nutrition needs for ultramarathon training in a neat summary. Next week I will review the second half of the position paper- nutrition demands for ultramarathon racing and supplements. Stay tuned!


Costa, R. J. S., et al. (2017). “Gut-training: the impact of two weeks repetitive gut-challenge during exercise on gastrointestinal status, glucose availability, fuel kinetics, and running performance.” Appl Physiol Nutr Metab 42(5): 547-557.

Cox, G. R., Clark, S. A., Cox, A. J., Halson, S. L., Margreaves, M., Hawley, A. J., Jeacocke, N., Snow, R. J., Yeo, W. K. & Burke, L. M. (2010). Daily training with high carbohydrate availability increases exogenous carbohydrate oxidation during endurance cycling. J Appl Physiol, 109: 126-134.

Hoffman, M. D. and K. Fogard (2011). “Factors related to successful completion of a 161-km ultramarathon.” Int J Sports Physiol Perform 6(1): 25-37.

Jeukendrup, A. E. (2017). “Training the Gut for Athletes.” Sports medicine (Auckland, N.Z.) 47(Suppl 1): 101-110.


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Comments 9

  1. golikov1r@mail.ru

    I do not even know how I ended up here, but I thought
    this post was good. I do not know who you are but certainly you’re going to a famous blogger if you
    aren’t already 😉 Cheers!

  2. Pingback: Thoughts, Notes, and Shares for June 21st, 2020 | Life at 50K

  3. As a sub-50kg ultrarunner, I can assure you that “eating enough calories” to match my energy output is NOT my biggest challenge (or even my biggest nutritional challenge)! Running 60+ miles a week barely gives me a calorie intake requirement of 2,000 a day (and don’t get me started on the problems of avoiding weight gain if injury or illness means I can’t run).

  4. Pingback: Key Takeaways from ISSN Position Stand on Ultrarunning Nutrition - Part 2 - Jason Koop

  5. Concerning the section on “Matching energy demands”, is the data provided on Strava about the amount of calories burned during a run accurate enough to guide me on replacing calories on a long run?

  6. I specifically held off on reading your summary until I read the whole paper myself so I could see if I had the same key takeaways as you did. I did not LOL Mine were still way too mired in minutia and overcomplicated. Thanks for the teachable moment, Jason!

  7. Great article, immediately useful in application as I come off a road marathon and start training for a 50 mile trail event. I recall well, during my initial assessment/mini-camp with Jason Poole back when he was coaching with you, I was preoccupied with endurance, strength training and technique on technical terrain and he told me, after about 4-hours running Green Mountain and surrounds, “I don’t think any of those are limiters for you. I think you’ve got a nutrition issue—THAT’s where your fatigue comes from.” He, and your team, were dead right.

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