Researchers from McMaster University in Canada led a study to explore how a sustained dietary calorie deficit might influence key health indicators in athletes. The findings indicate that extreme or long-lasting calorie restriction, along with lower carbohydrate intake, can contribute to the emergence of physical and mental health challenges in athletes. These observations align with reports from MedicalXpress regarding the potential consequences of restricted energy availability.
The condition that arises when athletes do not meet their energy needs is known as RED-S, or Relative Energy Deficiency in Sport. The term was introduced by the International Olympic Committee in 2014 to describe a spectrum of health and performance issues that stem from insufficient energy intake relative to expenditure. RED-S can occur whether the energy shortfall comes from intentional dieting and weight control or from excessive energy expenditure through training and competition without adequate energy replacement.
In their analysis, the researchers reviewed prior studies on nutrition as a tool for achieving elite athletic performance, while excluding data from individuals under 18 years of age. They developed a grading framework to gauge RED-S severity. In this system, athletes in the green zone can train and compete without noticeable impairment. The yellow zone signals the need for closer health monitoring. The orange zone calls for regular medical oversight and intervention, while the red zone indicates conditions that may require serious medical treatment and potential exclusion from training or competition.
Findings show that athletes in the red zone may experience hormonal imbalances, bone weakness, low iron stores, urinary issues, disruptions in glucose and fat metabolism, weakened immune defenses, and heart-related problems. Prolonged energy restriction can also take a toll on mental well-being, with increased risks of depression, insomnia, reduced motivation, and disordered eating patterns such as anorexia and bulimia. Moreover, lowering carbohydrate intake tends to push athletes more quickly toward the red zone by amplifying energy shortfalls. Social and environmental pressures, including media emphasis on body image and peer influence, play a significant role in shaping unhealthy eating behaviors among sports participants.
Experts emphasize that environmental pressures and exposure to social networks contribute to unhealthy eating patterns, underscoring the need for supportive environments, education, and proactive screening to protect athletes’ health and performance. Early recognition of energy deficiency and its manifestations can help teams and coaching staff address risk factors before serious complications arise, safeguarding both physical health and athletic longevity.
An important legacy of this work is the growing awareness of signs that may indicate disordered eating in athletes or loved ones. Early education and conversation can help detect concerns and guide individuals toward appropriate care and support.