Understanding Relative Energy Deficiency in Sport (RED-S): Risks of eating disorders in athletes

I first met Jennifer, a collegiate cross-country athlete, after her third stress fracture in 12 months. She was caught in a cycle of injury, recovery, returning to running and then re-injury. During our initial discussion, I discovered that she had not had a menstrual cycle in three years. She believed that being lighter would make her faster and that losing her period was a sign she was training hard enough.

I frequently encounter athletes who push their bodies to the limit in pursuit of their goals. While this dedication is admirable, it sometimes leads to unintended health consequences. One of the issues we see in athletes — particularly those training for demanding endurance events like marathons — is Relative Energy Deficiency in Sport (RED-S). This condition can significantly impact an athlete’s health and performance, leading to a higher risk of injuries and long-term health problems.

What is Relative Energy Deficiency in Sport (RED-S)?

Relative Energy Deficiency in Sport is a condition that occurs when an athlete‘s nutritional fueling is insufficient to meet the demands of their training and daily activities. Essentially, the “energy in” is less than the “energy out.” This energy imbalance can impact multiple areas of the body, including the endocrine, metabolic, hematologic, cardiovascular, gastrointestinal and immune systems. It also affects psychological health, leading to a cascade of well-being issues.

What are some signs and symptoms of RED-S?

Athletes with RED-S might exhibit a variety of symptoms, some of which may be subtle. These include:

• Frequent injuries: Repeated stress fractures, muscle strains and other injuries can be a warning.
• Delayed recovery: A harder time healing from injuries and taking longer to recover.
• Fatigue: Persistent tiredness and inability to recover well from training sessions.
• Hormonal effects: For female athletes, irregular menstrual periods, which may involve prolonged time between menstrual periods. For men, a hypogonadal state results in lower testosterone and decreased libido.
• Decreased performance: A noticeable decline in athletic performance such as running slower, reduced endurance, and impaired agility and coordination, despite rigorous training.
• Mood changes: Irritability, depression and anxiety.
• Gastrointestinal issues: Frequent stomach problems, such as bloating and constipation.
• Frequent illness: Recurrent colds or increased rate of “getting sick.”

What is the link between RED-S and eating disorders?

I categorize athletes experiencing RED-S into three groups: educational, disordered eating and eating disorder. The educational category consists of athletes who have increased their training load but have not adjusted their caloric intake to meet their heightened nutritional needs. These athletes are unintentionally underfueling. Usually, they see a quick turnaround after a few sessions with a sports nutritionist who helps them understand how to properly fuel their bodies for their increased activity levels.

The second group includes athletes with disordered eating behaviors. These individuals often have misinformed nutritional beliefs and engage in unhealthy eating practices, such as restrictive dieting (such as avoiding all carbohydrates or adhering to a very strict diet), skipping meals, severely restricting calories or exercising excessively to burn off consumed calories. These athletes typically require the combined efforts of a sports nutritionist and an eating disorder psychologist to help them understand proper nutrition and overcome food-related anxieties, including expanding the variety in their diets.

The last group consists of athletes with clinical eating disorders, such as anorexia nervosa, bulimia nervosa and binge eating disorder. These athletes often need comprehensive care in an intensive outpatient or residential setting. Many times, they present for treatment after sustaining an injury, such as a stress fracture, due to the severe impact of their eating disorder on their overall health.

Risks and consequences of RED-S and eating disorders:

RED-S and eating disorders can affect every aspect of an athlete’s health and performance and have both short- and long-term effects.

Some of the key risks include:

Bone health

Insufficient energy intake can lead to low bone mineral density, increasing the risk of stress fractures and osteoporosis. In younger athletes, this can lead to not reaching peak bone mineral density in their late 20s, overall shortening the timeline for developing osteoporosis in adulthood.

Hormone imbalance

For the female athlete, RED-S can cause menstrual dysfunction. This not only affects fertility in the future, but is also correlated to bone health problems as estrogen is one of the key components for maintaining bone mineral density. In males, RED-S can lead to decreased testosterone levels, which impact libido, muscle growth and strength.

Metabolic risks

Prolonged energy deficiency can lower an athlete’s daily, basic rate of burning calories (basal metabolic rate). This slows gut motility, lowers heart rate, and further complicates energy balance and nutrient absorption.

Cardiovascular health

Chronic energy deficiency can impair heart function. In high-risk situations, this can increase your risk of future health conditions and even death.

Mental health

RED-S has psychological impacts, including increased anxiety, depression, and preoccupation with food and body image. This can deteriorate overall well-being and performance.

Preventing or treating RED-S

Given the complications associated with RED-S, it is ideal to address these issues proactively if possible.

As a college athlete or a participant in an organized sport, you may be regularly screened for RED-S. If you don’t have a screening program that you’re involved in, you can ask your healthcare team to consider evaluating you based on screening and follow-up steps that may involve:

Education and awareness

At Arizona State University, we provide a yearly presentation to the athletic trainers on signs and symptoms of RED-S. As an athlete, it is crucial for you to be aware of RED-S and understand the risks it poses. You, along with your athletic trainers, coaches and other healthcare professionals, should be educated on how to monitor for RED-S to ensure your well-being and optimal performance.

Early detection

Regular screening for signs of RED-S and eating disorders should be a part of your routine medical check-up. Here at ASU, we perform an annual screening with the Eating Disorder Screen for Athletes (EDSA), which helps us identify higher risk individuals prior to the start of the season.

Nutritional support

If you have questions or are unsure whether your calories and nutrient intake is what your body needs for your level of activity, seek the advice of a dietitian.

Psychological support

Counseling and therapy can be valuable in addressing the psychological aspects of RED-S and eating disorders. Do not hesitate to seek support if you are dealing with these issues.

Medical management

In severe cases, medical intervention may be necessary to address the physical health consequences of RED-S and eating disorders. This is typically within a residential or inpatient treatment facility. From an outpatient perspective, many of the athletes I see with disordered eating have routine blood work and check-ins to monitor for secondary issues such as anemia from nutritional deficiency. If you have any concerns about RED-S, start with your primary care team or a sports medicine healthcare professional who has knowledge about RED-S.

Creating a supportive environment

A nonjudgmental environment helps you stay consistent with your nutritional goals. Coaches, teammates, friends and family are key components of your support system. Encouraging healthy attitudes toward food, body image, and training can significantly reduce the risk of RED-S and eating disorders.

Relevant reading

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