RED-S

by GRP dietician Megan Chacosky

With the latest update to the International Olympic Committee’s Relative Energy Deficiency in Sport (RED-S) Consensus released last month, it feels pertinent that sport communities of all kinds take time to better understand RED-S, how it occurs, who it might affect, and how we can continue to learn to take better care of ourselves and our teams while we chase athletic pursuits.

What is RED-S?

Relative Energy Deficiency in Sport, or RED-S, refers to impaired physiology, psychology, and sport performance as a result of an athlete experiencing problematic low energy availability. In a prolonged state of low energy availability - when energy expenditure consistently enough and drastically enough exceeds energy intake - the body starts to make metabolic shifts to preserve the most vital, energy-requiring functions; this results in decreased (or entirely halted) functioning of other physiological roles within the body, as well as barriers to peak performance: 

Why does RED-S occur or continue?

Low energy availability that leads to RED-S is most often a result of decreased energy intake or increased energy expenditure - or a combination of the two - from either an intentional (e.g. eating disorder, restricting certain types of foods or food groups, excessive exercising, etc.) or unintentional (e.g. transitioning to a new training plan, limited access to food, lack of awareness around nutrition needs, etc.) origin. While acute phases of low energy availability may occur, like missing a few snacks or meals with a busy schedule or being a little bit behind on energy balance throughout a multi-race weekend of competition, these are often quickly correctable when adequate nutrition is consumed and may never lead to greater RED-S effects. However, extended periods or patterns of low energy availability will almost always lead to negative outcomes in health and performance.

Who does RED-S affect?

While the origins of RED-S research began with the 2005 International Olympic Committee’s findings of the Female Athlete Triad affect (low energy availability leading to amenorrhea and low bone mineral density in women), perhaps one of the most impactful updates since 2018 of investigating more athlete populations is the greater comprehension around a similar, but more difficult to identify phenomena of disrupted hormones and low bone mineral density in male athletes as well. Regardless of sex, athletes in general - compared to their non-athlete peers - are more likely to experience low energy availability, RED-S, and/or eating disorders. Adolescent athletes, in particular, are at a higher risk of experiencing acute or long-term phases of low energy availability due to their elevated basal metabolic needs throughout growth and development, limited access to or interest in nutrition information about reaching energy balance, and social pressures to alter weight or food practices.

Beyond age, stage of development, and sex, the types of sports athletes compete in can potentially predispose some athletes to be at a higher risk of experiencing RED-S:

  • High training volume sports (ultra-endurance, swimming, distance running, etc.)

  • Athletes entering new training environments or entering a heavy phase of training without effective fueling and recovery strategies

  • Eating disorders/disordered eating behaviors (intentional low energy availability)

  • Participation in weight sensitive sports:

    • Aesthetically judged sports – rhythmic and artistic gymnastics, figure skating, diving, artistic swimming, aerial skiing

  • Endurance sports – long distance running, cross-country skiing, biathlon, road cycling, triathlon

  • Gravitational sports – mountain biking, sport climbing, ski jumping, horizontal/vertical jumping

  • Weight-class sports – horse racing, lightweight rowing, weightlifting, combat sports, (e.g., wrestling, boxing), bobsled, skeleton

As an athlete, or a person around athletes (e.g. parent, coach, teacher, etc.), what can I be doing to help prevent RED-S in my sport communities?

First and foremost, RED-S is not something that can be supported or mended alone; ideally, this process includes a team of medical professionals (e.g. a physician, psychologist, and dietitian) to work alongside athletes and coaches, setting best practices for training and fueling to better protect athlete health. Even though as coaches or parents you might be the first to notice or address a RED-S related athlete concern, reaching out to a team of clinical providers for more guidance around physical and mental health parameters is a critical initial step.

Within a team setting, whatever your role, creating and strengthening an environment of safety for athletes to share or address concerns related to eating disorders, body image, and mental health is another deeply impactful way to reduce RED-S incidence and provide proper support for any existing issues. Some actions that can help facilitate a safer environment:

  • Make sure staff/coaches are setting a clear, consistent message that athlete health is (and always will be) more important than athlete performance. We will not sacrifice an athlete’s health in exchange for greater performance; in fact, athletes should understand that they cannot truly reach peak performance if they are in poor health.

  • Remember that authenticity is more important than authority - even when you don’t have all of the answers, just listening and being present with an athlete who is struggling is a great first step. Offer to find more information to help, or continue the conversation, and follow through.

  • Be intentional about the culture you are contributing to around food, weight, body image, etc. Understand that you might also have some biases around nutrition or body image; be extra mindful about if, when, and how you discuss or demonstrate these beliefs.

  • Have parents, coaches, and athletes take the WithAll pledge to reduce harmful weight and diet talk in sport settings. Or, create your own team contract or code of conduct for all to sign.

In a more immediate, day to day sense of how to support athletes, see below for guidance on patterns of shifts to athlete behavior that might signal a deeper issue:

While the IOC’s 2023 release expounded upon the previous 2018 RED-S research - to include a deeper understanding of mental health precursors or additional outcomes, RED-S in Para athletes, RED-S in lactating or post-partum athletes, and better identifying RED-S in male athletes - this will continue to be an area of sport research we are learning about for many years to come. If you are an athlete, or work with athletes, the first step towards preventing or rectifying RED-S is familiarizing yourself with RED-S, and associated signs, symptoms, and outcomes. Hungry for more? Check out the links below for further reading and resources outlining RED-S and the pursuit of prioritizing athlete long-term health.

Where can I learn more about RED-S?

Biathlon, Cycling, Running, Sculling, Skiing, TrainingLuke Browndiet, RED-S, Megan Chacosky, nutrition, coaching