Not eating enough while undergoing tough training regimes is putting athletes’ health at risk, according to a Consensus Statement by international and Australian scientists, published by the International Olympic Committee (IOC) in the British Journal of Sports Medicine.
Relative Energy Deficiency in Sport (REDs) develops when athletes fail to consume as much energy as they expend over long time periods. Despite an estimated prevalence ranging from 15% to 80% across different sports, the syndrome often goes unrecognised because ‘sports culture’ encourages restricting calorie intake.
“Athletes themselves, their coaches, and team clinicians may unwittingly exacerbate this ‘sports culture,’ because of the perceived short-term gains on performance from intentionally or unintentionally limiting calorie intake,” the Statement said.
REDs was first recognised as a distinct condition by the IOC in 2014, and the new Statement draws on advances in REDs science over the past five years, with the aim of promoting wider recognition and prevention of the syndrome and improving athlete health, psychological wellbeing, and performance.
In particular, the Statement highlights new evidence on the emerging role of inadequate carbohydrate intake; the overlap between REDs and overtraining syndrome; the time course of REDs development; the interplay between mental health and REDs; and advances in the understanding of the syndrome in male athletes and para-athletes.
It includes a summary of practical clinical guidelines both for assessing persistent calorie deficit and for safe body composition measurement that deliberately excludes under-18s, plus an updated clinical assessment tool (IOC REDs CAT2) incorporating a 4-colour traffic light system to assist accurate diagnosis and assessment of risk/severity.
Lead author and IOC Games Group member, Professor Margo Mountjoy, explained that this ranges from full participation in training and competition (green) to continued monitoring (yellow) through to intensive medical interventions and monitoring (orange) all the way to full medical support, coupled with possible removal from competition and training (red).
“REDs is common in both male and female athletes in many sports, and although we understand a lot more about its causes, awareness of the syndrome and its consequences for health and performance is still low among athletes, their medical and performance support teams, and the public,” she said.
A deficit in the amount of available energy needed to maintain optimal health and athletic performance is referred to as low energy availability (LEA), and while in the short term, the body can adapt to this, it cannot cope with large, prolonged, and frequent deficits in available energy, which leads to REDs.
“While age, gender, genes, external factors, and behaviours may worsen or mitigate the effects, these can be many and varied as the body is forced to divert energy from processes involved in growth, reproduction, and maintenance,” Professor Mountjoy said.
“For example, the evidence suggests that although the outcomes of REDs are similar to those found in female athletes, it seems as if the threshold of available energy before REDs symptoms appear is lower than that proposed for female athletes: two emerging potential indicators of REDs in male athletes are low libido and decreased morning erections, both of which have been identified as physiological consequences of problematic LEA.
“We very much hope that this Consensus Statement will enhance awareness and understanding of REDs and stimulate action by sports organisations and scientists, and athlete health and performance teams to protect the health and wellbeing of the many athletes at risk of this syndrome.”
The effects of REDs can include:
- Hormonal disturbances, loss of periods, erectile dysfunction, low libido
- Weakened bones, susceptibility to stress fractures
- Abdominal pain, cramps, bloating
- Impaired energy metabolism
- Low iron, insufficient red blood cell oxygen carrying capacity (haemoglobin)
- Urinary incontinence
- Impaired glucose and blood fat (lipid) metabolism
- Depression, exercise dependence/addiction, eating disorders
- Impaired cognitive skills, such as memory, decision-making, spatial awareness
- Sleep disturbances
- Heart rhythm and blood flow abnormalities
- Reduced muscle function
- Reduced growth and development
- Impaired immunity
Not to mention the impacts on performance.
Evidence for the time it takes to develop REDs is still emerging, with short-term LEA starting to be defined as a few days to weeks, medium-term as weeks to months, and long-term as months to years.
“But further scientific validation is required, as the time course may differ between the sexes, and change according to the severity and duration of LEA,” the Statement noted.
However, recent research shows that low carbohydrate availability speeds up the development of REDs as it is associated with poor bone health, lowered immunity, and depleted iron, sometimes even in the absence of LEA.
Similarly, it has been demonstrated that there is considerable overlap between the symptoms of REDs and overtraining syndrome. This occurs when an athlete does not adequately recover after repetitive intense training, and can include fatigue, declining performance, and susceptibility to injury.
“This overlap emphasises the importance of excluding low energy and/or low carbohydrate availability before diagnosing overtraining syndrome,” the Statement said.
“Short term intentional or unintentional LEA can boost performance and garner approval from the coach and the sports culture, but these short term ‘positives’ make it even more challenging for athletes to recognise the longer-term implications of REDs.”
As such, disordered eating behaviours, eating disorders, and/or REDs are common among some athletes, and may be worsened by social media, societal pressures, the athlete’s training/coaching entourage, a belief that a specific physique/weight/appearance will improve performance and/or overall body dissatisfaction.
In terms of prevention, the Statement highlighted that there was a lack of solid evidence on the most effective ways of raising much needed awareness of REDs and its causes and consequences among athletes, coaches, parents, and athletes’ health and performance teams.
For example, less than half of coaches and physicians surveyed were able to identify the three components of the female athlete triad, and other studies reported similar knowledge gaps among physiotherapists and athletic trainers.
“But once diagnosed, the existing body of research on restoring energy availability for health and sport performance suggests that dietary interventions are the most effective,” Professor Mountjoy said.
“Notably, the various consequences of REDs improve at different rates, and the duration and severity of LEA may influence time to recovery. We recommend a comprehensive team approach for successful recovery, to include sports medicine specialists, nutritionists, psychologists, and sports scientists, together with coach and family involvement.
“And given the potentially serious outcomes of REDs, early identification and timely interventions should be prioritised.
“Future research—and there needs to be a great deal more of it, using standardised methodology—needs to triangulate data from cross-sectional, long term, and well-designed interventional studies, to uncover the complexity of the relationship between LEA and REDs.”