The red zone: low energy availability in male athletes

Low energy availability is well-recognized in female athletes. However, aesthetic, weight class, and lean sports may require male athletes to achieve and maintain unhealthy body-composition profiles. Marianke van der Merwe takes a deep dive into low energy availability in male athletes and discusses how pushing them into the red zone may be detrimental to their long-term health.

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Aesthetic, weight class, and lean sports require athletes to have a specific weight and physique for optimal performance(1). Unfortunately, this pressures athletes to look a particular way and causes them to adapt to unhealthy eating, exercising, and weight monitoring patterns(2,3). As a result, disordered eating (DE) starts to arise and moves along a spectrum from health to disease(4).

The DE leads to low energy availability (LEA) due to a significant difference between energy intake and expenditure during exercise, causing insufficient availability for growth, health, and homeostasis. The abovementioned is known as relative energy deficiency in sport (RED-S). In female athletes, RED-S leads to the female athlete triad, which is a combination of LEA, low bone mass density (BMD), and menstrual dysfunction(4). However, male athletes only present with LEA and low BMD, making identification and treatment of disordered eating patterns extremely challenging(5).

Disordered eating continuum

Eating disorders (ED) have high mortality rates and are serious mental illnesses that negatively impact an individual’s quality of life(3). The DE continuum starts with healthy eating and exercise behaviors, which then progresses to more extreme weight loss and dieting to meet the required standards of the sport. The pathological continuum starts at subclinical EDs such as anorexia athletica (AA) and ends with clinical EDs such as anorexia nervosa (AN), bulimia nervosa (BN), and eating disorders not otherwise specified (EDNOS), along with other medical complications that impair performance(2). The signs and symptoms of disordered eating impair an athlete’s performance and become a part of their daily living and significantly impact their family, social life, and work or school (see table 1)(3).

Table 1: Signs and symptoms of disordered eating(7)

Systems Signs Symptoms
General·         Sudden weight loss/gain or fluctuations·         Hypothermia
·         Failure to gain/grow weight as adolescent for growth ·         Fatigue
Oral/dental and throat·         Oral trauma/lacerations·         Recurrent sore throat
·         Dental erosion/carries
·         Parotid enlargement
·         Perimolysis
Gastrointestinal·         Diarrhoea ·         Abdominal pain
·         Hematemesis ·         Delayed gastric emptying
·         haemorrhoids·         Gastroesophageal reflux
·         Constipation
Endocrine·         Infertility ·         Loss of libido
Neuropsychiatric·         Memory loss/concentration·         Depression/anxiety
·         Insomnia
·         Obsessive-compulsive behavior
·         Self-harm
·         Suicidal attempt
·         Oedema
Cardiorespiratory·         Palpitations ·         Chest pain
·         Shortness of breath·         Hypotension
·         Oedema ·         Bradycardia
Musculoskeletal·         Low bone mineral density
·         Stress fractures
Dermatological ·         Lanugo hair
·         Hair loss
·         Yellowish skin discoloration
·         Russell’s sign
·         Poor skin healing
·         Self-harm evidence
Genitourinary and renal·         Electrolyte disturbances


High-risk sports for disordered eating(6)

  1. Endurance sports.
  2. Weight category sports (judo, boxing, and wrestling).
  3. Aesthetic sports, gymnastics, and high board diving.


Disordered eating leads to increased injury risk and inconsistent performances(6,4). Inadequate nutrition, impaired bone health, and hypogonadotropic hypogonadism start to arise, which causes overall health and performance decrements(4). The ‘male athlete triad’ has been proposed as a combination of LEA, low BMD, and hypogonadotropic hypogonadism(4).

Health and performance consequences

Health and performance consequences in elite athletes with DE depend on the form and duration of DE behavior and the physical demands of the sport(2). Unhealthy nutritional habits, sudden weight loss methods, excessive exercise, and pressure to perform or look a certain way results in DE(2). It is important to note that not all athletes will present with a psychological component, but this does not mean they do not suffer from DE(2).

Extreme weight control methods include fasting, counting calories, abuse of diuretics, obsessive weight checking, vomiting, laxatives, and excessive exercise(7,5). This causes electrolyte disturbances and, combined with self-induced vomiting, laxative and diuretic use, and extremely low body weight is the main reason for death from cardiac arrhythmias(7). Furthermore, stressing about the right body composition, denying hunger, and fearing fatness and weight gain is mentally exhausting and places the athlete in a vulnerable psychological state(7,3). Male athletes with low energy availability are predisposed to bone stress injuries such as stress fractures, electrolyte abnormalities, and dehydration, which ultimately lead to poor sports performance(7).

Bone health

Peak bone growth for males occurs at 14 years old, emphasizing the importance of healthy nutritional behaviors for optimal bone strength, function, and density (8). Bone marrow adipocytes secrete leptin and adiponectin (adipokines); however, DE causes leptin levels to be extremely low, resulting in diminished reproductive function and altering bone turnover(8).

Neuroendocrine changes

Hypogonadotropic hypogonadism refers to the measurable hormonal changes that influence reproduction and metabolism(4). Prolonged nutritional restriction harms multiple endocrine systems and hormonal regulation to preserve essential bodily functions(8). There are the four major neuroendocrine systems through which the hypothalamus and pituitary direct neuroendocrine function (see table 2).

Table 2: The four major neuroendocrine systems through which the hypothalamus and pituitary direct neuroendocrine function(4,8).

Neuroendocrine systemFunctionEffects of disordered eating
The Hypothalamic-Pituitary-Adrenal axisPlays an important role in the body’s response to stress. Hypoglycemia and hypoinsulinemia, which further promotes cortisol release to assist the body in maintaining blood glucose levels.
The Hypothalamic-Pituitary-Gonadal axisInvolved in the development and regulation of the reproductive system and immune system.Presents with low testosterone levels in men and pubertal males experience the conversion of testosterone to estrogen, negatively affecting bone formation and increasing bone resorption.
Hypothalamic-Pituitary Thyroid axisMaintain normal, circulating thyroid hormone levels essential for the biological function of all tissues. Diminished levels of thyroid hormone negatively affect bone health.
Growth Hormone-Insulin-Like Growth Factor I axisRegulates linear growth in children.The decrease in insulin-like growth factor I (IGF-I) via the liver decreases along with declines in both body fat and body mass index (BMI) (8).

Risk factors

The risk factors that contribute to the development of eating disorders are multi-factorial. Clinicians divide risk factors into three groups: predisposing, trigger, and perpetuating factors(3). Predisposing factors include genetics, low self-esteem, body dissatisfaction, perfectionism, bullying, and peer pressure(2,3). On the other hand, Trigger factors refer to body shaming, negative comments about weight, body composition, and injury(3). Lastly, perpetuating factors refer to what these athletes or non-athletes use to continue/maintain their disordered eating patterns, such as a coach or significant other approval(3).

Looking more closely into sport-specific factors, it is evident that sport creates an environment that places athletes in a vulnerable position, perfect for DE patterns. Sports focus highly on body composition, weight classes, and leanness are all perfect examples of this type of environment. The initial loss of weight followed by improved performance drives the athlete to continue with restrictive eating and excessive exercise patterns, which ultimately lead to DE(2,3). The pressure intensifies as the athlete progresses through the competitive levels(2,5,1). For example, financial pressures through contracts and endorsements can cause them to take extreme measures to maintain their performance to preserve their livelihoods(5).

Injuries play a big role because they place the athlete in a negative physical and mental position. The athlete initially gains weight and realizes they cannot compete in games or championships, making them vulnerable to developing DE(3). Coaches play a big role in DE development as a coach obsessed with having to look and perform in a specific way adds stress and fear of fatness(3). Furthermore, rules and regulations of sports force athletes to look a certain way which places significant pressure on them, knowing that it could hinder them from competing in the desired weight class or competing at all.

Screening and diagnosing

It is of utmost importance for clinicians to understand the epidemiology and pathophysiology of eating disorders for accurate screening and treatment measures(7). The preparticipation physical examination (PPE) monograph includes numerous questions aimed at identifying disordered eating behaviors and is supplemented with questions regarding bone health, mood disturbance, substance use, and a thorough family and athlete history(7,8). The 28-item paper-based eating disorder examination questionnaire (EDE-6.0) is also a great way to identify DE and consists of four subscales: dietary restraining, eating concerns, shape concern, and weight concern(1). Clinicians can also utilize a bone density scan to assess bone mineral density. Finally, vitamin-D screening may provide insight into skeletal health.


Eating disorders are primarily psychiatric illnesses; thus, athletes require intense therapeutic intervention by an experienced therapist for long-term recovery(8). Therapy aims to address underlying body dissatisfaction, and for some, psychopharmacology plays a vital role in treating co-morbid conditions such as anxiety, obsessive-compulsive disorder, and depression(8). The therapist should be an expert in treating eating disorders in athletes and knowledgeable about the factors specific to men(5). Success can only be obtained by optimal functioning of the interdisciplinary team, as they all play a significant role in the performance and health of the athlete.

Focusing on behavioral and cognitive theories is one approach that addresses all the factors at play(5). Furthermore, adding psycho-dynamic orientated techniques can bring about meaningful changes(5). A dietitian is influential and vital in nutritional rehabilitation for healthy weight restoration and bone health recovery(8). Using supplements is easier to successfully restore required dietary needs when dealing with DE athletes(8).

Treatment protocols for vitamin D deficiency for children and adolescents include 2000 IU daily for six weeks, followed by maintenance therapy of 1000 IU per day. Adults require 6000 IU daily for eight weeks, followed by maintenance therapy of 2000 IU per day. Treatment for vitamin D insufficiency includes 1000 IU daily. Due to the risk for poor bone health in AN and DEs, ongoing supplementation of 400–1000 IU daily is required once normalization of vitamin D levels is achieved(8). Vitamin D3 is the desired choice as it is more potent and supports cortical bone mass better than vitamin D2(8).

Once an athlete restores a healthy weight, clinicians can incorporate weight-bearing physical activity to aid in bone health treatment(8). These biomechanical forces promote healthy growth, especially among adolescents(8). Ongoing medical supervision is vital to ensure continuous monitoring of physiologic function during recovery. In addition, it may direct inpatient or residential care if outpatient treatment fails to achieve treatment goals(8).



Eleven strategies to reduce the likelihood of disordered eating(3,4,5,6,7).

  1. Be aware of the signs and symptoms of disordered eating.
  2. Consult a registered dietitian for appropriate nutrition for optimal performance.
  3. Focus on creating ways for athletes to enhance performance other than changing their weight.
  4. Talk honestly and openly about the importance of nutrition for optimal athletic performance.
  5. Use validated screening equipment for early identification of risk factors.
  6. Ensure that all stakeholders understand the DE risk factors.
  7. Refer athletes to appropriate professionals early.
  8. Encourage athletes to seek help for all mental health concerns.
  9. Multi-disciplinary teams should develop individualized nutritional and training plans for athletes.
  10. Create a supportive environment that encourages athletes to make the best of themselves.
  11. Clinicians should handle body composition goals with sensitivity and confidentiality.



Aesthetic, weight class, and lean sports create a toxic environment that forces athletes to use extreme weight loss measures to perform at the required level. This leads to the development of disordered eating and excessive exercise patterns that negatively affect the quality of life of the athletes. It is important to be aware of the signs and symptoms and risk factors to identify athletes at risk early. Proper screening is required to ensure the athlete receives the best possible care.


  1. Turk J Sports Med 18th November, 2018
  2. BMJ Open Sp Ex Med 2020;0:e000801
  3. Euro J of Sport Sci, 2013, 13:5, 499-508
  4. Sports Med (2016) 46:171-182
  5. Clin Soc Work J (2016) 44:114-123
  6. Asian J of Sports Med, Vol 1 (No 2), June 2010, p63-68
  7. Br Sports Med 2016;50:154-162
  8. Metabolism: Clinical and Experimental, 2015, 64(9):943-951
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