DE may range from what is commonly perceived as normal dieting to reflecting some of the same behaviour as those with eating disorders, but at a lesser frequency or lower level of severity.

DE in an athlete sits on a spectrum between optimised nutrition and an ED, and may include some of the criteria for diagnosis of an ED. Both DE and dieting behaviour are common indicators for developing an ED.

The 2019 International Olympic Committee (IOC) consensus statement on mental health in elite sport compares characteristics of ED versus DE (Reardon et al. 2019)

Individual athletes can move back and forth along the spectrum of eating behaviour at any point in time over their career and within different stages of a training cycle (e.g. during the off-season, pre-season, when injured). Athletes are more likely to present with DE than a clinical ED, however, there are health and performance implications regardless of where an athlete falls along the spectrum, as risks increase when DE worsens into a diagnosable ED.

Behaviour that was previously ‘encouraged and rewarded’ such as losing weight to enhance performance, may result in a failure to maintain adequate energy availability required for training and competition demands. These behaviours may not have been maladaptive at first, but may develop into problematic eating behaviour and worsen to reflect ED psychopathology.

Familiarisation with ED diagnostic criteria among members of an athlete’s support network facilitates appropriate questions about eating behaviour. Feeding and eating-related disorders are defined by specific criteria published in the American Psychiatric Association’s (2013) Diagnostic and Statistical Manual of Mental Disorders (5th edition, DSM-5).

Disordered eating and low energy availability can occur together, or in isolation. Identification of one necessitates the investigation of the other.

Inappropriate eating practices can have detrimental effects on sports performance. In addition to the direct impairment of physiological and psychological function, DE can increase the risk of illness and injury, compromise training quality and consistency and indirectly interfere with competition goals.

When starved of energy, the body responds by reducing its metabolic rate. Since the human brain operates at a very high metabolic rate, and uses a substantial portion of total energy and nutrient intake, the brain is particularly vulnerable to inadequate fuel for its brain function. A person with DE may struggle to make decisions, solve problems and regulate their emotions. Restricted eating, malnourishment, and excessive weight loss can lead to changes in brain chemistry, resulting in increased symptoms of depression and anxiety.

All of these may affect the athlete’s performance, their ability to engage in day-to-day tasks, their capacity for insight into problems associated with their eating, and their ability to engage with psychological treatments.

Three categories of sports, defined as aesthetically judged, gravitational and weight class, are consistently identified as high risk for the development of DE and EDs. Successful performance in these sports generally involves individual, or combinations of, features such as low body mass, leanness, high power to weight ratio, subjective judgements on appearance and rapid weight loss for weigh-ins. It should be remembered however that athletes are at risk of DE and ED across all sports and these high-risk categories are neither exclusive nor exhaustive.