It is estimated 58 percent of athletes are at risk of a condition called RED-S, but what exactly is it? We asked the experts to find out more, what the symptoms are and how to avoid it.

Just a trigger warning here: we talk about eating disorders and weightloss in this article.

What is RED-S?

Pronounced ‘reds’ or ‘red-s’, RED-S stands for Relative Energy Deficiency in Sport. It occurs when an athlete’s body doesn’t have enough energy to keep up with the demands of their exercise, on top of their essential daily functions.

Lots of athletes can get into this state after a particularly hard run or race if they fail to fuel themselves sufficiently before, during and after.

This won’t necessarily have adverse outcomes if they fuel and rest well in the days to follow, as going into energy deficit isn’t too serious if it isn’t a regular occurrence. But if it happens repeatedly, a chronic energy imbalance will occur that can have major and long-lasting health implications.

Is RED-S only something that athletes experience?

No – it can happen to anyone who is exercising regularly. “Some people will get into energy deficit without even realising it,” explains Pippa Woolven, the founder of Project RED-S. “Low energy availability might occur if you have upped your training without also upping what you eat; if you have a suppressed appetite after running for longer distances so don’t eat for a while; or if you just didn’t have time for a decent meal after training.”

For others, it might occur because they have made the conscious choice to lose weight, or because they are following a certain diet that doesn’t include enough variation of nutrients.

What’s it like to suffer from RED-S?

Pippa’s story

Pippa, 29, experienced RED-S herself, which is why she has now dedicated her work to raising awareness, improving prevention, and increasing recovery from the condition. “I often find the best way to explain how easily RED-S can occur in anyone, at any time, is by sharing my story,” she says.

An early flair Pippa was a talented junior runner, winning English Schools titles and GB vests. When she was in her 20s, she took up steeplechase and hoped to compete in the Olympics.

She thought that, in order to get to the next level, she would need to be leaner and train harder. “I drew the conclusion that if I wanted to be an Olympian, I had to eat more healthily and increase my training,” she recalls. “At first it worked wonders, I lost a little weight and started to morph into the picture of what I thought an elite athlete looked like.

“I was getting compliments from coaches and teammates who thought I looked so lean. I started to perform well, which was unfortunate as it led me to believe this is what I had to keep doing to run well.”

A misunderstood condition

Pippa continues: “It wasn’t that I had a typical eating disorder like anorexia. I was still eating, but it wasn’t nearly enough to fuel the exercise I was doing, and not enough of a varied diet as I was always ‘clean’ eating.”

It wasn’t long until Pippa’s performance started to drop. She started getting more running injuries, more illnesses that took a long time to shift, and she felt constantly tired.

“I qualified for the Commonwealth Games in 2014 at the steeplechase and I really under-performed,” she said. “I couldn’t understand why. By this point,

I had lost my menstrual cycle but I hadn’t thought it was a big deal. When I told a doctor, they put me on the pill, which didn’t solve the problem but masked it.”

It got to the point where Pippa couldn’t string together a full week of training, or even get through the day as a student, as she was so fatigued. “I still thought training harder was the answer and my problem was lack of fitness,” she admits.

Pippa saw numerous doctors and had lots of tests but didn’t get diagnosed with RED-S because at the time it was a little-understood issue.

A lightbulb moment

“I finally came across the blog of an athlete who described exactly what I was going through,” Pippa said. “She used the term RED-S and it was a lightbulb moment. It was then I could get the help I needed via specialists, who helped me learn about nutrition and how to change my ways of thinking when it came to my body image and attitude to training.”

Pippa was able to make a full recovery and went on to represent GB again in cross country championships, but she still wonders what might have been. “I lost a number of years including two Olympics.

Who knows what I could have achieved if I hadn’t had RED-S? That’s why I am passionate about helping others so they can avoid going through what I did.”

What are the causes of RED-S?

The condition affects men as well as women, and it can impact anyone at any level of sport, not just the elite.

“There can be so many ways an athlete can fall into a state of RED-S. It can happen intentionally (by deliberately cutting back on calories), or unintentionally (if you don’t understand, or underestimate, the energy requirements of the exercise you are doing),” Pippa explains.

For those who deliberately underfuel, it could be because of a belief that thinner means faster, fuelled by comparisons to team-mates, role models and images in the media.

Perfectionists and those with a Type A personality can be more at risk because they are always striving for better, and more likely to have the ‘go hard or go home’ mentality that can be prevalent in some sections of the fitness industry.

In other cases, those with RED-S can have clinical eating disorders such as anorexia and bulimia, often caused by more complex psychological issues.

Some people won’t have been diagnosed with an eating disorder, but might have ‘disordered eating’, which means they are following a diet they believe is really healthy, but one that actually cuts out major food groups such as carbs.

What are the symptoms of RED-S?

Feeling constantly fatigued is a common symptom. Pippa says this is more than just feeling tired from training but an inability to have the energy to get through the day.

Running performance will start to stagnate and deteriorate, despite training harder. Sufferers are more likely to get injuries such as stress fractures, and illnesses like chest infections, because they have low bone density and a weak immune system.

The lack of energy available to the body means it will start shutting down functions that are not essential, such as the reproductive system. “It’s a bit like a phone shutting down background apps to preserve battery power,” Pippa explains.

As a result, women’s periods can become irregular or stop altogether. This has health implications not only for fertility, but because it can also make bone density weaker.

Digestive issues can also occur because the digestive system won’t have enough energy to run optimally.

Mood-wise, sufferers can feel depressed, irritable and have anxiety around their diet and body image. They might have body dysmorphia or be in denial that they are not eating well.

How can RED-S be prevented?

To avoid under-fuelling, there are a few things you can do. Firstly, don’t leave it too long between meals and have snacks in-between.

If you increase your training, increase what you’re eating too. It’s important for women to avoid fasted training so try to eat within an hour of exercising. If you find you don’t initially have an appetite, Pippa advises drinking a high-carb protein shake, or chocolate milk, and then following this up with a meal a short time later.

When it comes to your diet, she adds: “There is such a thing as eating too healthily. It’s much better to have a balanced diet which includes all the food groups you need for nutrition but also allows that bag of crisps or chocolate bar too.”

Factor in your other daily activities when it comes to fuelling too. This might be a strength class, a long dog walk, or pushing children around in a buggy. Also, take into account if you are under work stress, having major life changes such as moving house, or starting university. These might all influence when and what you eat and lead to under-fuelling. Here’s an expert guide on what to eat before running.

RED-S and mental health

On the mental health side, Pippa warns to be aware of the dark side of fitness culture. She explains: “There is a lot of nonsense we can be fed via the media and social media about having the perfect beach body or elite frame. Focus on skill and training, rather than weight and appearance.”

She continues: “‘You do you’ is one of my favourite quotes. You have to understand your own energy balance and your own body. Don’t compare your training and your body to someone else, as we are all different.

“I used to think the path to success meant training harder, making sacrifices and eating less. In fact, I’ve since realised that it should involve easy training, quality sleep and balanced nutrition. Of course there should be hard work involved, but tempered with these other things. Sport should be fun and we should be in it for our long-term health, not short-term goals.”

For further support with RED-S

If you are struggling with any of the issues raised in this article, then don’t suffer in silence. Reach out to your family and friends. Contact your GP.

Pippa’s Project RED-S website (RED-S.com) is jam-packed with more information on the condition and has recommendations for medical experts who can help. It’s well worth a visit if you’re an athlete, coach, or parent to a young runner.

The book More Fuel You: Understanding your body & how to fuel your adventures by Renee McGregor (reneemcgregor.com), is an excellent resource for understanding the nutritional requirements of exercise. Renee is a sports dietitian, specialising in eating disorders and RED-S.

BEAT is a UK charity offering information and support on eating disorders.

“Don’t ever think you are alone and that there isn’t someone who can help you,” urges Pippa.“The earlier you seek help, the better your long-term outcome. With the right support and knowledge, I got my health back, my menstrual cycle returned, and I was able to return to the sport I love again. Whatever your level or goals, don’t let RED-S stand in the way.”