Relative Energy Deficiency in Sport (REDs) Identification and Recovery: The Energy Availability Continuum Under the 2023 IOC Consensus

No Longer Called the “Female Athlete Triad”—It’s REDs

Relative Energy Deficiency in Sport (REDs), proposed by the IOC in 2014, describes the cascade of negative health and performance outcomes when athletes experience prolonged low energy availability (LEA; insufficient energy intake relative to exercise expenditure). The 2023 IOC Consensus (supported by over 170 original studies accumulated since 2018) brings three key conceptual updates:

1. Energy availability is a continuum: From “adaptable LEA” (mild, short-term, reversible) to “problematic LEA” (associated with multiple adverse REDs outcomes), it is not black and white.
2. Not limited to females: The role of low carbohydrate availability is highlighted, and data on LEA effects in males have increased—male athletes experience REDs too.
3. Not the same as an eating disorder: Many cases of REDs stem from unintentional energy deficiency (training volume increases without food intake keeping pace), not necessarily involving disordered eating.

Why Endurance Athletes Are a High-Risk Group

Prolonged high energy expenditure + cultural pressure equating “light” with “fast” + appetite regulation lagging when training volume increases make endurance athletes (especially females, but males as well) a high-risk group for LEA. The consequences span multiple systems: skeletal (decreased bone density, elevated risk of bone stress injuries), endocrine (menstrual dysfunction/decreased testosterone), metabolic, cardiovascular, mental health, and performance itself (endurance, strength, training response, and injury recovery are all impaired).

Identification: Warning Signs and Screening

Signals that warrant heightened vigilance:

The 2023 Consensus provides the IOC REDs CAT2 three-step clinical tool: Step 1 screening; Step 2 severity and risk stratification; Step 3 clinical diagnosis and treatment. This is a framework used by professional medical teams—the role of athletes and coaches is to “stay vigilant and refer early,” not to self-diagnose.

The Recovery Pathway (Core: Restoring Energy Availability)

The fundamental treatment for REDs is not some supplement or therapy, but correcting the energy deficit:

1. Increase energy intake and/or reduce training expenditure: Bring energy availability back into the non-problematic range (individualized, requiring sports dietitian involvement). The focus is often on “eating more” rather than just “training less.”
2. Pay special attention to carbohydrate availability: The 2023 Consensus emphasizes the role of low carbohydrate availability; adequate carbohydrate replenishment during recovery is key.
3. Multidisciplinary team: Physicians, sports dietitians, psychologists, and coaches collaborate; those with an eating disorder component need psychological intervention.
4. Bone monitoring: Those with a history of bone stress injuries need bone density assessment and follow-up; bone recovery is measured in years and requires patience.
5. Menstrual/endocrine recovery as an indicator: Natural return of menstruation in females (not masked by contraceptives) is an important signal of improved energy status.

Prevention Over Treatment

A major focus of the 2023 Consensus is enhancing awareness among professionals and coaches to reduce REDs risk. In practice: proactively increase food intake alongside training volume, regularly review “energy availability” rather than just body weight, investigate recurrent injuries and performance plateaus as possible energy signals, and foster a team culture that does not equate “thin” with “fast.”

The most dangerous aspect of REDs is that it is often misread as “feeling off—just train harder”—but for a body in energy deficit, adding more training only pushes the continuum further toward the problematic end.

“It took us a decade to make this clear: low energy is not a badge of discipline; it’s the body being drained. When an athlete has recurrent fractures, amenorrhea, and can’t improve no matter how much they train—the answer is almost never that they aren’t training enough; it’s that they aren’t eating enough.” —A sports medicine and REDs research clinician

Related Reading

• RED-S Relative Energy Deficiency: Energy Supply Warning Signs for Female Athletes
• Relative Energy Deficiency (RED-S): The Most Dangerous Dietary Pitfall for Endurance Athletes
• Relative Energy Deficiency (RED-S): Causes, Warning Signs, Effects on Bone and Endocrine Health, and How to Seek Help
• RED-S Relative Energy Deficiency: The Most Overlooked Health Breakdown in Endurance Athletes