The Cost of Under-Fueling: Eating Disorders, Amenorrhea, and RED-S in Athletes

Thanks to Isabelle Law (Dietetic Intern, University of Alberta) for writing this blog post!

References are in brackets.

The Pros & Cons of Sports:

Sports are often celebrated for its many physical and mental health benefits, with research confirming that participation in both team and individual sports can enhance mental well-being and improve social outcomes across populations of all ages and genders.1 Being part of a team and engaging in regular physical activity can provide structure, a sense of community, and stress relief (1-2).

However, certain aspects of sport can make it difficult for athletes to maintain their physical and mental health (2). Athletes face unique stressors including time constraints, performance pressures, and social isolation, that can increase their vulnerability to mental health challenges (2-3). While the physical demands and risk of injury in sport are well known, the cumulative impact of both physical and mental strain on energy balance and nutrition is often overlooked.

In recent years, the understanding of how under-fueling affects athletes' health and performance has grown significantly. Eating disorders, amenorrhea, and Relative Energy Deficiency in Sport (RED-S) are now recognized as serious health concerns rather than just unfortunate consequences of competitive sport culture (4).

Eating Disorders in Athletes:

Studies show that eating disorders are more common in athletes than in the general population. Reported prevalence rates range from 0–19% in male athletes and 6–45% in female athletes (5,6). Athletes participating in sports that emphasize leanness for performance such as gymnastics, figure skating, rowing, endurance events, and anti-gravity sports like ski jumping are at higher risk of developing eating disorders (7).

The wide variation in the reported prevalence of eating disorders in sport is due in part to the different methods used to assess eating disorders in research. Still, the true prevalence may be even higher, as athletes often underreport mental health and eating concerns (7). This underreporting is particularly common among male and transgender athletes, where stigma surrounding eating disorders may be higher (8). The underreporting of eating disorders in sport may partly stem from the normalization of disordered eating behaviours within athletic environments. Pressure from coaches or peers and a fear of losing performance advantages can discourage athletes from seeking help. These behaviours are frequently dismissed as “part of being an athlete,” which reinforces unhealthy weight control practices such as skipping meals, cutting out entire food groups, or caloric restriction with a goal number that is not adequate for athletes (7,9).  

Menstrual Dysfunction and Amenorrhea:

Amenorrhea is also known as “the absence of menstruation.” This is a common and serious symptom of low energy availability in female athletes (10). It can be classified as:

• Primary amenorrhea: When menstruation hasn’t started by age 15

• Secondary amenorrhea: When menstruation stops for three months (if cycles were previously regular) or six months (if irregular)

Some athletes also experience oligomenorrhea, which refers to inconsistent or irregular menstrual cycles (10).

Menstrual disorders are more commonly observed among athletes in sports like gymnastics and endurance events. However, athletes in team sports such as volleyball and soccer also experience these issues at rates higher than the general population. For example, up to 54% of rhythmic gymnasts may experience primary amenorrhea, compared to the general population prevalence of less than 1%. In sports like cycling and triathlon, secondary amenorrhea is especially common (10).

The overall prevalence of menstrual disorders in athletes may be as high as 61%, depending on the sport (11). However, these numbers are likely underestimated, as many female athletes underreport menstrual dysfunction. This may be due to normalization of amenorrhea by some (but not all!) coaches or medical professionals, the prioritization of athletic performance, or the mistaken belief that the absence of menstruation is a sign of fitness (11).

Understanding RED-S:

Over the last decade, the concept of Relative Energy Deficiency in Sport (RED-S) has replaced the previously used term Female Athlete Triad to describe the broader impacts of under-fueling in sport (12). While the Female Athlete Triad focused on the link between low energy availability, menstrual dysfunction, and low bone mineral density in female athletes, RED-S includes athletes of all genders and highlights a wider range of negative health outcomes (12).

RED-S occurs when an athlete's energy intake from food/beverages is not enough to support both the energy they use during exercise and the energy their body needs to function properly. This causes a condition known as low energy availability, where the body doesn't have enough fuel left over for processes like hormone production, bone health, and immune function (11). While RED-S may be caused by eating disorders or disordered eating behaviours, it can also happen unintentionally if athletes do not eat enough to keep up with the demands of intense training (4).

With no singular diagnosis of RED-S, the exact prevalence in athletes is unknown. Research suggests that up to 79.5% of female athletes and 70% of male athletes present with indicators of RED-S (4). You can have RED-S without an eating disorder, and it can affect both recreational and elite athletes of all body shapes and sizes.

Common symptoms for both men and women include: difficulty thinking clearly, negative changes to mood, frequent illness, a plateau/decline in performance regardless of training, suppressed sex hormones, or altered thyroid hormones. For women, amenorrhea is a common indicator of RED-S, and can serve as a both a sign or symptom of the condition (4). Low energy availability can be both a cause and consequence of disordered eating and menstrual dysfunction (11).  

In addition to compromising athletic performance, RED-S impacts multiple body systems. It can lead to decreased muscle strength and endurance capacity, and increased risk of injuries. Long-term consequences may include hormonal deficits, or decreased bone density which increases the risk of stress fractures (7).

The treatment for RED-S seems simple: restore energy balance by eating more, reducing training, or both. However, this may be difficult to do if the athlete is experiencing symptoms of an eating disorder, such as fear of weight gain, or anxiety when making food choices. It can also be difficult because diet culture (and an obsession with thinness) is deeply engrained in our society.

We need to raise awareness to foster a shift in sports culture.

In conclusion, the intersection of eating disorders, amenorrhea, and RED-S highlights the serious impact of low energy availability in sport. While performance may be the initial concern, the long-term health consequences can be far more significant (4). Increasing awareness of the prevalence and underreporting of eating disorders, amenorrhea, and RED-S among athletes is essential for improving detection, prevention, and ultimately fostering a shift in sports and athlete culture to one that prioritizes proper fueling and long-term health over short-term performance gains.

References:

1. Eather,N.,Wade,L.,Pankowiak,A.,&Eime,R.(2023).TheImpactofSports Participation on Mental Health and Social Outcomes in adults: a Systematic Review and the “Mental Health through Sport” Conceptual Model. Systematic Reviews, 12(1), 1–27. https://doi.org/10.1186/s13643-023-02264-8

2. Vanderkruik,R.(2024,July19).MentalHealthinSports|MassGeneralBrigham. www.massgeneralbrigham.org; Mass General Brigham. https://www.massgeneralbrigham.org/en/about/newsroom/articles/the-importance -of-mental-health-in-sports

3. Gavrilova, Y., Donohue, B., & Galante, M. (2017). Mental Health and Sport Performance Programming in Athletes Who Present Without Pathology: A Case Examination Supporting Optimization. Clinical Case Studies, 16(3), 234–253. https://doi.org/10.1177/1534650116689302

4. Mountjoy, M., Ackerman, K. E., Bailey, D. M., Burke, L. M., Constantini, N., Hackney, A. C., Heikura, I. A., Melin, A., Pensgaard, A. M., Stellingwerff, T., Sundgot-Borgen, J. K., Torstveit, M. K., Jacobsen, A. U., Verhagen, E., Budgett, R., Engebretsen, L., & Erdener, U. (2023). 2023 International Olympic Committee’s (IOC) consensus statement on Relative Energy Deficiency in Sport (REDs). British Journal of Sports Medicine, 57(17), 1073–1097. https://doi.org/10.1136/bjsports-2023-106994

5. Bratland-Sanda, S., & Sundgot-Borgen, J. (2013). Eating disorders in athletes: Overview of prevalence, risk factors and recommendations for prevention and treatment. European Journal of Sport Science, 13(5), 499–508. https://doi.org/10.1080/17461391.2012.740504

6. Eichstadt, M., Luzier, J., Cho, D., & Weisenmuller, C. (2020). Eating Disorders in Male Athletes. Sports Health: A Multidisciplinary Approach, 12(4), 194173812092899. https://doi.org/10.1177/1941738120928991

7. Aron, C. M., LeFay, S., & Rodriguez, R. R. (2023). Eating Disorders in Sport. Springer Nature Link, 247–267. https://doi.org/10.1007/978-3-031-36864-6_16

8. Nickols, R. (2024, March 8). Eating Disorders and Athletes - National Eating Disorders Association. National Eating Disorders Association; NEDA. https://www.nationaleatingdisorders.org/eating-disorders-and-athletes-2/

9. Fatt, S. J., George, E., Hay, P., Jeacocke, N., Day, S., & Mitchison, D. (2024). A systematic review and meta‐synthesis of qualitative research investigating disordered eating and help‐seeking in elite athletes. The International Journal of Eating Disorders/International Journal of Eating Disorders, 57(8), 1621–1641. Wiley. https://doi.org/10.1002/eat.24205

10. Gimunová, M., Paulínyová, A., Bernaciková, M., & Paludo, A. C. (2022). The Prevalence of Menstrual Cycle Disorders in Female Athletes from Different Sports Disciplines: A Rapid Review. International Journal of Environmental Research and Public Health, 19(21), 14243. https://doi.org/10.3390/ijerph192114243

11. Verhoef, S. J., Wielink, M. C., Achterberg, E. A., Bongers, M. Y., & Goossens, S. M. T. A. (2021). Absence of menstruation in female athletes: why they do not seek help. BMC Sports Science, Medicine and Rehabilitation, 13(1). https://doi.org/10.1186/s13102-021-00372-3

12. Nazem, T. G., & Ackerman, K. E. (2012). The Female Athlete Triad. Sports Health: A Multidisciplinary Approach, 4(4), 302–311. https://doi.org/10.1177/1941738112439685