Current views on relative energy deficiency in sport (REDs)

Relative energy deficiency in sport (REDs) is a clinical syndrome which includes the adverse effects on health and performance caused by chronic low energy availability. This article explores the current view of REDs, highlighting the recent updates from the International Olympic Committee consensus statement issued in September 2023. Psychological factors and mental health are recognised as having a reciprocal relationship with both the aetiology and outcome of the chronic low energy availability that leads to REDs. This has important implications in terms of prevention and management for individuals experiencing REDs. Unintentional or intentional unbalanced behaviours around high levels of exercise and insufficient nutrition lead to a situation of low energy availability. Low energy availability is not synonymous with REDs; rather, cumulative and sustained low energy availability, particularly low carbohydrate availability, leads to the clinical syndrome of REDs comprising a constellation of adverse consequences on all aspects of health and performance. Furthermore, REDs is not synonymous with an eating disorder (ED), although some individuals may have disordered eating or an ED. REDs can potentially arise in both biological sexes, at all ages and all levels of exercise. This is of particular concern for the young aspiring athlete or dancer, where behaviours are being established and in terms of long-term consequences on mental and physical health. The mechanism of sustained low energy availability leading to these negative health outcomes is through the adaptive down-regulation of the endocrine networks. Therefore, raising awareness of the risk of REDs and implementing effective prevention and identification strategies is a high priority.