Relative Energy Deficiency in Sport (RED-S)

"Do you find yourself feeling run-down even though you’re training hard and eating what seems like a healthy diet?"

"Have your workouts started to feel harder than usual, and your performance is declining?"

"Have you lost your menstrual cycle or noticed frequent injuries that just won’t heal?"

What Is RED-S?

Relative Energy Deficiency in Sport (RED-S) is a medical condition caused by insufficient energy intake to support the demands of training and daily bodily functions. It often affects athletes or active individuals who unintentionally (or intentionally) underfuel their bodies due to rigid food rules, aesthetic pressures, or disordered eating patterns.

While it’s closely related to the Female Athlete Triad (low energy availability, menstrual disturbances, and low bone density), RED-S is broader — affecting both men and women , and impacting multiple body systems including metabolism, hormonal health, cardiovascular function, immunity, and psychological well-being.

Globally, studies suggest that up to 60% of female athletes and up to 33% of male athletes may be affected by low energy availability (LEA) — the root cause of REDs (Tenforde & Barrack, 2016; Logue et al., 2020).

In the United States, research estimates that 36–58% of female athletes (particularly in endurance and aesthetic sports) and 25–45% of male athletes experience symptoms consistent with REDs or LEA (Mountjoy et al., 2018; Ackerman et al., 2019).

Despite its prevalence, RED-S often goes undiagnosed — partly because its symptoms can be subtle, normalized in sport culture, or mistaken for just "overtraining" (Mountjoy et al., 2018).

RED-S and Disordered Eating

Many people with RED-S don’t realize they’re underfueling — especially when their diets appear “clean” or “healthy.” But beneath that, there may be:

• Chronic restriction of calories or certain food groups
• Preoccupation with body image or weight
• Fear of gaining weight or "undoing" meals with exercise
• Unintentional neglect of nutrition due to busy schedules or stress

These behaviors can fall under disordered eating , which is a major contributor to RED-S. Over time, they disrupt the body's ability to recover, regulate hormones, and maintain bone and cardiovascular health.

What To Do If You Think You Have RED-S

The good news? RED-S is reversible with the right approach. Here’s what to do:

Increase Energy Intake Eat more than you think you need — especially carbohydrates and fats Prioritize consistent meals and snacks , especially around workouts Let go of rigid food rules or guilt around eating Adjust Training Volume or Intensity Temporarily scaling back allows your body to recover and restore brain hormonal balance. The brain can turn back on hormone production. Prioritize Recovery & Sleep Rest isn’t laziness — it's a core part of high performance and muscle healing Work With Professionals A registered dietitian, physician, or physical therapist can help guide recovery. If disordered eating is a factor, an eating disorder specialist and psychological support are key.

REDs isn’t just about food or fitness — it’s about finding balance between your energy input/output and your body’s needs. Being active and pushing limits is great, but not at the cost of your health.

Listening to your body, fueling it properly, and respecting rest can take your performance — and overall wellness — to a whole new level.

If you think you might be dealing with REDs, don’t hesitate to seek support. The earlier you catch it, the smoother your recovery will be.