Low energy availability and REDs - are recreational trail runners at risk?

You may remember seeing a blog I wrote about 18 months ago with the title ‘What you need to know as a trail runner about low energy availability and RED-S’ – if not, then click the link and have a read.

In the last blog, I invited trail runners and walkers to take part in an online survey for my master’s research – this blog is to share the research findings and some helpful resources. And on that note, a big thank you to everyone who participated in my survey as I couldn’t have done this without your valuable input.

What is low energy availability and REDs?

To start with, I think it’s probably good to do a quick recap from last blog to help clarify what these two terms mean:

An athlete can enter a state of low energy availability (LEA) if they have not eaten enough to provide energy for exercise and normal body functions. When our body does not have enough energy available for normal body functions (e.g. reproduction, muscle recovery), we start to see these gradually shut down. If this state of LEA is prolonged and/or severe, this can result in a range of health consequences, reduced sport performance and an increased risk of injuries.

To describe the effects of LEA on our body, scientists have grouped all the common health and performance symptoms and given it the name REDs (Relative Energy Deficiency in Sport). Since the last blog, the International Olympic Committee has released an update to the REDs framework, and now the two conceptual models (as seen below) have LEA in the centre showing how LEA is the main contributing factor to REDs.

REDs Health Conceptual Model (source: read here)

REDs Performance Conceptual Model (source: read here)

As trail runners, we may be at higher risk of LEA and REDs due to the high energy demands of our sport which comes from running over varied terrain, in various weather conditions, in remote locations, and over long distances and event durations. I think it’s important that we as recreational trail runners don’t solely rely on the general healthy eating guidelines of ‘eat less, move more’ – instead we need to ‘fuel for the training and event’ so that we always have enough energy for both running and normal body functions. As you can see in the diagram below, a well fueled machine results in optimal energy availability (EA) i.e. you have enough fuel for both running and normal body functions and reduce your risk of symptoms related to REDs.

Note: This figure is based on daily intake. Reduced EA may be tolerated for short periods; sustained periods of LEA can have severe health and performance consequences.

We also need to remember that we generally don’t need to have a high energy intake every day – on rest days or low intensity training days/periods our energy intake may be lower than on our long run days. So, it’s important to think about varying your energy intake with your daily/weekly training load and training purpose. If you would like personalised support with a nutrition plan, please seek professional advice from a Registered Dietitian or Registered Nutritionist who specialises in sports nutrition.

So, what was this research about?

We investigated the association between risk of LEA and nutrition knowledge in trail runners and walkers in Aotearoa/New Zealand. Nutrition knowledge is important for all athletes to ensure they know how to fuel for the training they are doing, which in turn may also reduce the risk of LEA. Studies have shown that both elite and recreational athletes, across both sexes and particularly in endurance sports such as running, can be at risk of LEA. However, limited research has been done in recreational trail runners and walkers. For this reason, we felt it was important to increase our understanding of how differing levels of nutrition knowledge may be linked to risk of LEA in recreational trail runners and walkers.

Data collection

Data was collected between June and December 2022. Participants were asked to complete an online survey in two parts – part one included trail running questions and a questionnaire to assess risk of LEA, part two included nutrition knowledge questions. A total of 217 participants completed part one of the online survey, 152 participants completed both part one and part two.

Results - low energy availability

Most participants were trail runners, with just a small proportion of trail walkers (for analysis we grouped these together as ‘trail runners’). The average age was 42 for females and 48 for males. Participants ranged from beginners to very experienced trail runners who participated in short 5-9km distance events through to ultramarathons.

In our study, 31% of females and 23% of males met the classification for ‘LEA risk’. Common symptoms of LEA include (but are not limited to) gut discomfort, frequent injuries, fatigue, low mood/motivation for training, poor performance and recovery, menstrual cycle changes (for females), and lowered sex drive (for males).

Our results showed that females in the LEA risk group were more likely to have experienced periods of absence from training due to injury in the past year and were more likely to suffer from abdominal bloating and stomach cramps than females with low LEA risk. Females with LEA risk were also more likely to experience menstrual dysfunction, compared to those in the low LEA risk group.

In males, those with LEA risk experienced lower sex drive and were also more likely to have suffered from abdominal bloating compared to males in the low LEA risk category. The scores from male participants with LEA risk also indicated issues with fatigue, recovery and energy levels. We did not find any evidence that female or male participants with LEA risk had lower nutrition knowledge than those with low LEA risk.

As all our data was anonymous, we cannot give individualised feedback regarding participants’ LEA risk scores. However, if you regularly experience any of these symptoms try out this checklist from the Australian Institute of Sport. If you feel you are ticking a lot of these boxes, it doesn’t necessarily mean that you are in a state of LEA, however it may be worth investigating. If you would like personalised support, please seek professional advice from a Registered Dietitian or Registered Nutritionist who specialises in sports nutrition.

Results - nutrition knowledge

Our results on the nutrition knowledge survey showed that the average score on the general nutrition knowledge section was 78 out of 100. Areas that were answered well (correct answers by more than 75% of participants) included identifying the roles of macro- and micronutrients and food groups; areas that were answered poorly (correct answers by less than 50% of respondents) included identifying food sources of calcium and understanding the roles of fat.

The results on the sports nutrition knowledge section, showed that the average score was 65 out of 100. The area that was answered correctly was around training/competing in hot environments; and areas that were answered poorly (correct responses by less than 50% of participants) included strategies for gaining lean mass, and fuel for during events.

How to fuel during events is a critical component in the overall concept of eating enough to fuel for performance. As this area received the lowest score of all (8.8% correct), we’ve created a brief practical resource to support recreational trial runners and walkers with some tips on how to appropriately fuel during events.

Click here to download the resource

Where can I learn more?

• Sports Dietitians Australia – Food for Your Sport: Trail Running and Ultra-Distance Running
• Sports Dietitians Australia Factsheets – e.g. hydration, recovery nutrition
• Australian Institute of Sport checklist – Are you eating enough to fuel your performance
• Mysportscience academy – sports nutrition blogs and webinars (free and subscriptions)
• Fueling Endurance – podcast on nutrition for runners, cyclists and triathletes
• The Female and Male Athlete Triad Coalition – information on LEA and energy deficiency
• PEAKS-NQ – free online questionnaire with individualised feedback summary to test your general and sports nutrition knowledge
• Athlete Diet Index – free online questionnaire with individualised feedback summary to assess your current dietary intake