Written by Kai McClelland
In my freshman year of college cross country, there were eight girls in my recruiting class. Three of us had career-ending injuries before our sophomore year was over.
I learned the hard way that my own injury was linked to under eating. A burning pain in my hip turned into a stress reaction in my sacrum, which ultimately ended my career in the NCAA. I didn’t have an eating disorder and I wasn’t on a team where weight was a fixation; my coaches would even tell us that they’d prefer if we overeat instead of undereat. However, being a college athlete meant that I had an overloaded schedule and no time. I could barely remember to tie my shoes, much less make time to eat.
I was drawn back to that memory while chatting with Lindsey Cortes on a sunny Wednesday morning. Cortes is a sports dietician, a former competitive athlete, and most recently, a mother. She held up her 5-month-old son, Levi, to the camera right as we started our conversation, her hair draping over her shoulders next to his face. I asked her the question I ask all new moms: how do you have time to do anything? (Cortes’ answer: you don’t.)
Eventually, Levi fell asleep, and Cortes and I got to our main topic of conversation: RED-S. Relative energy deficiency in sport (RED-S) is a syndrome of poor health and declining athletic performance that happens when athletes don’t get enough fuel to support the energy demands of their daily lives and training. It impacts everyone, but it’s hit the women’s distance running community hard, taking many of us out of the sport for good. Below is a transcript of our conversation:
Kai: First of all, for people that don't know what it is, what is RED-S?
Lindsey: RED-S is a myriad of symptoms that your body might be experiencing when you’re underfueling. When you're pushing your limits in a game, competition, or race, your body goes into fight or flight mode. It can’t tell the difference between playing a basketball game and running from a bear, so it puts all of its energy towards physical performance as it would if you were actually in a life-or-death situation. So when you’re participating in sport, your energy isn’t going towards things like supporting hormones, metabolism, muscle recovery, bones, and GI health, which are essential for your life. That’s why even a slight amount of underfueling can start to cause problems.
So when people develop RED-S, they might start to notice issues with their hormones. They might develop a depressed mood, skin problems, GI issues, bone density issues, and other issues with internal health and metabolism.
I think a really big thing to note, though, is that underfueling doesn't have to mean that you're eating a small amount. A lot of athletes feel like they eat a lot, especially in relation to their peers, but how much you should eat is relative to what your body needs to fuel for your sport. People really underestimate the metabolic demand that exercise and training puts on your body, especially when it's [to the level] of an elite athlete.
Kai: So do athletes have to intentionally diet to develop RED-S, or can it be caused by something as simple as forgetting to make time to eat?
Lindsey: Underfueling can be completely unintentional. And that's why we see it a lot in the college population: student-athletes are so busy. When coupled with the fact that the jump from high school to college athletics is a big increase in the physical demand placed on your body, college students are very prone to developing RED-S.
Kai: What are some other eating patterns that are red flags for RED-S?
Lindsey: Skipping meals is absolutely a warning sign for underfueling. That's a big issue. Not eating before and after practice is another one. Eating “diety foods”, like going for almond milk or skim milk instead of whole milk, is also a red flag. There’s a lot of dietary messages floating around in our society that confuse athletes. People are told to choose the lower calorie option or low sugar option, but in the end, eating those foods instead of whole ones can hurt the athlete and lead to unintentional RED-S.
Kai: And once an athlete starts to develop RED-S, what are the consequences?
Lindsey: It's very individualized. For some people, even the slightest bit of energy deficit will start to cause underperformance in sport. Other people won’t see performance issues right away, but other internal health issues will pop up. They may say, “I’m still performing great, but I’ve been injured three times this year and my hair is falling out.”
Hormone suppression is another thing that comes up as RED-S progresses. For women and girls, they might start to miss their period, which is a big red flag that your hormones are being suppressed. For boys and men, their testosterone and thyroid levels will be suppressed. They don’t have the same monthly signal that women and girls do, but they’ll experience other symptoms, like decrease in libido, etc.
So where I'm going with this is that as your internal health changes and as your hormones get suppressed, you're not going to respond to your training as well. You are going to get injured. Estrogen and testosterone play a huge role in your bone development. In the distance running population, when those stay low, we start to see stress fractures.
Basically, whether you notice it right away or not, performance will take a toll eventually. For some people, it takes a little longer to kick in. And frankly, when it does kick in, it can be pretty severe.
Kai: So we’re both runners, and we keep going back to distance running. In the distance running community, a lot of athletes have been pressured to lose weight. There’s this idea of “skinnier equals faster” that’s been pushed on a lot of athletes. Is RED-S a potential consequence of subscribing to that mentality?
Lindsey: I think a really important side note here is that your body size is not a reflection of how much you eat. I'm not a big fan of BMI as a marker of health, but I will say that there is a point in BMI where underweight is underweight, and that’s a BMI of under 18. When you get too low, your risk of morbidity and mortality increases.
Everyone is really scared of weighing too much, but there’s actually a huge range of “healthy” that isn’t reflected by BMI. In fact, if you look at studies of all-cause morbidity and mortality, the healthiest population is actually in the “overweight” category with a BMI of 25 to 29.
I’m mentioning this to debunk BMI a little bit and make sure that people know that nutrition intake isn’t reflected by body size. You can have RED-S at any BMI or size. With that being said, especially in the running community, I think there is a good push right now to debunk the “skinnier is better” mentality. I think that's good. Everybody comes in different sizes, and our nutrition needs are separate from our size.
Kai: Going in a bit of a different direction: who is most at risk for RED-S?
Lindsey: Nobody is immune to it, but it can happen to women more quickly. Men and women have different physiology and different hormones. So if men fast for 8 to 12 hours, they might not see any negative long-term effects. However, when women fast for just four hours–literally just the difference between breakfast and lunch–we start to see changes in our hypothalamus that trigger something called the HPA axis, which affects our thyroid and metabolism long-term. Basically, it signals to your body, “hey, we’re in a state of energy deficiency” even just for that short period of time.
It doesn’t mean that men should try to “get away with it” or that men don’t get RED-S, but it does impact women more quickly. I think a better explanation is that if a man goes on a diet for a week but then stops, no long term harm is done. If a woman does the same thing, it might screw up her hormones for an entire month.
Kai: Are there specific sports where you see RED-S being more common?
Lindsey: RED-S can happen in any sport. The culture and physical demands of distance running can make it pretty common among runners. And for runners, RED-S can cause stress fractures and take people out of the sport completely. That’s devastating.
Gymnastics and dance are other examples where I see RED-S quite a bit. Other aesthetic sports are similar because athletes are judged for how they look as well as how they perform. In fact, any sport that has weight associated with it can put athletes at risk for RED-S, like lightweight rowing, cycling, boxing, etc.
In sports like these, under-fuelling can be unintentional. It’s just the culture of the sport. It's like, “well, my teammates are eating salad, so I'm going to eat salad, too”. We want to normalize plates full of pasta and proteins and fats so that these athletes are getting the fuel they need.
Kai: Does having ADHD put an athlete at risk for RED-S?
Lindsey: Yes, athletes with ADHD are another population at risk because they might be at risk for skipping meals accidentally or having a suppressed appetite due to symptoms caused by medication.
Kai: For the athletes that are reading this, what factors could allow them to self-identify whether or not they might be experiencing RED-S?
Lindsey: Diagnosing RED-S is very difficult. For example, GI issues aren’t just a RED-S thing. They can be caused by so many other things. If you’re wondering whether or not you have RED-S, it doesn't hurt to explore that possibility with a qualified sports dietitian. You can ask them how you can improve your nutrition, whether or not RED-S might be causing some of the symptoms you’re having, etc.
I also have a quiz on my website. It’s not scientifically validated, but it might help an athlete see if there’s a possibility that they have RED-S. But diagnosing RED-S requires consulting with a sports dietitian. I’d advocate for a sports dietitian in particular over other professionals: a doctor might look at blood work, a PT might look at injuries, but at the end of the day, the root of all the symptoms is whether or not you’re fueling enough to meet the demands for your sport. That’s what a sports dietitian specializes in.
Kai: Let's say an athlete goes and talks to a sports dietician and it turns out that they have RED-S. How should they start to recover?
Lindsey: It depends on what your symptoms are. For example, if the underfueling is unintentional, it might just take one meeting with a sports dietician to set up a better fueling schedule and learn some better foods. That’s if a person feels like they can hold themselves accountable for eating those foods and not falling off track. If someone is struggling with body image or is otherwise nervous to eat more, engaging in work with a therapist and dietician together may be more appropriate. And then if people are struggling with the physical side of things, like altered hormones, amenorrhea, or injuries, we've got a loop in an endocrinologist, a sports physician, or a physical therapist into your treatment as well. I’d also say an OBGYN for women.
Kai: How long would it take for their performance to recover?
Lindsey: That’s highly variable. If somebody has only been underfueling for three months, they might start feeling better in a month or three. If they’ve been underfueling for years, it might take longer. It just depends on their body. The sooner you start to recover, the better off you’ll be in all regards.
*The above transcript has been edited for clarity and conciseness.
Athletes with further questions can check out @female.athlete.nutrition to get in touch with Lindsey.
Lindsey Cortes MS, RD, CSSD is a sports dietician and nutrition coach living in Texas. She is a former Division 1 Track and Field athlete and the owner and founder of Rise Up Nutrition. Prior to starting her business, she worked as a sports RD at the University of Georgia, Florida State University, and as a lead tactical dietician with US Air Force Special Operations. She also contracts with the University of Texas at San Antonio and supports our US Military Troops with tactical nutrition. She is passionate about helping female athletes overcome disordered eating and use food as fuel to support optimal performance. Cortes also has an account with over 15,000 followers on Instagram (@female.athlete.nutrition).