Articles
RED-S in Athletes: Under-Fueling Signs, Diagnosis, and Prevention
Are you an athlete who struggles with poor sleep, low energy, constantly getting sick, frequent stress fractures, and mood changes? There’s a chance that you might have RED-S.
Key Takeaways
- RED-S (Relative Energy Deficiency in Sport) happens when an athlete doesn’t eat enough to fuel training, daily life, and recovery — it can occur unintentionally or from restrictive eating.
- RED-S is the updated, all-genders version of what used to be called the female athlete triad.
- Common signs include poor sleep, chronic fatigue, frequent illness or stress fractures, loss of menstrual periods, low bone density, and mood changes.
- Under-fueling affects nearly every body system: metabolism, immune function, hormones, protein synthesis, growth, sleep, mental health, and athletic performance.
- Diagnosis uses the IOC’s REDs CAT2 tool in three steps: initial screening, risk stratification (green/yellow/orange/red), and diagnosis with a medical team.
- Prevention comes down to three things: fueling adequately every day (not just training days), working with a sports dietitian, and prioritizing rest and recovery.
What Is RED-S (Relative Energy Deficiency in Sport)?
RED-S stands for Relative Energy Deficiency in Sport. It occurs when an athlete does not consume enough energy (food) to support their body during the demands of their sport. Low energy availability can occur unintentionally, such as underestimating energy needs or forgetting to eat. It can also be associated with intentional dietary restriction, excessive exercise without adequate fueling, or disordered eating/an eating disorder.
This condition used to be referred to as the female athlete triad. This newer concept was introduced in 2014 by the International Olympic Committee as a broader term. One of the main new components is that RED-S considers all genders, not just females. The triad diagnosis required three things:
- Low energy availability (not eating enough to keep up with the energy your body uses each day and during exercise)
- Irregular or loss of periods (amenorrhea)
- Low bone density (weak/brittle bones)
The broader term does focus partly on the three components of the triad, but in addition to acknowledging all genders, it also encompasses many other factors:
How Under-Fueling Affects the Body: 8 Systems at Risk
- Metabolism: If it is not receiving enough fuel, your body will slow down metabolism to preserve energy. You may notice constantly being cold, tired, and fatigued.
- Immune function: You need a healthy immune system so your body can fight off illness and infection. Without enough food, your body struggles to do so. You may notice it takes you longer to recover from being sick, and you are getting sick more often than usual.
- Cardiovascular health: This is the health of your heart. When deprived of the nutrients it needs, your body starts using your muscles for energy to keep you alive. The heart is a muscle, so it can be affected by prolonged inadequate fueling. You may notice lower blood pressure, a slowed heart rate, and poor circulation leading to cold intolerance.
- Protein synthesis: This is when your body builds and repairs your muscles, which is super important for athletes. Your body can’t do this without adequate protein and overall caloric intake. You may notice a slower recovery time after exercise and difficulty building/maintaining strength.
- Growth and development: For young athletes, not consuming enough energy can slow down growth, puberty, and bone development.
- Psychological Health: This is your mental and emotional well-being. Chronic energy deficiency can also affect cognitive function, mood, and overall mental well-being. This contributes to feelings of fatigue, irritability, and decreased motivation.
- Sleep and Recovery: You may experience poor sleep, longer recovery times, and constant fatigue, causing training to become harder over time.
- Athletic performance: This is your ability to successfully train, perform, and progress in your sport. Insufficient energy intake can lead to decreased strength, endurance, and coordination.
How Is RED-S Diagnosed? The 3-Step CAT2 Screening Process
The REDs CAT2 (Relative Energy Deficiency in Sport Clinical Assessment Tool Version 2) is typically what is used. It was developed by the International Olympic Committee to evaluate and determine the risk of RED-S in a three-step process.
Step 1: Initial Screening
This includes various screening questionnaires. There are many to consider using depending on the situation, but some examples include:
- LEAF-Q (Low Energy Availability in Females)
- LEAM-Q (Low Energy Availability in Males)
- EDE-Q (Eating Disorder Examination Questionnaire)
- EAI (Exercise Addiction Inventory)
When the symptoms of RED-S start appearing, such as the ones mentioned above (loss of menstrual period, rapid weight loss, frequent injuries and illnesses, etc.), it can signal a need to discuss these questionnaires with athletes. Ideally, athletes would even complete some of these screening tools annually.
If deemed at risk, then Step 2occursr,s which is:
Step 2: Risk Stratification
Athletes are then assessed more closely to determine their level of risk. They are then placed into one of four risk levels, shown as a traffic light:
- Green: Low risk
- Yellow: Some risk
- Orange: Higher risk
- Red: High risk
Step 3: Diagnosis & Treatment Plan
Athletes that fall within the yellow, orange, or red zones need to receive a medical assessment and then treatment. Treatment includes a team consisting of a doctor, sports dietitian (preferably eating disorder informed), and therapist/sports psychologist if needed. A doctor (preferably a sports medicine doctor) needs to make the final diagnosis.
How to Prevent RED-S: Fueling, Nutritional Support, and Recovery
This condition is very preventable, and here are three main ways to help prevent you from developing RED-S.
- Fuel Adequately. Not eating enough is the main risk factor for developing this condition. This means consuming enough energy (food) to keep up with how much energy you are expending. However, it is important to understand that this means more than just fueling your sport! We need enough energy to support training, daily life, school, recovery (so even the days where you are not active,) and all your body’s normal functions.
- Nutritional Support. Working with a sports dietitian can be very helpful in understanding what your body needs, as it is highly individualized and there is not a one-size-fits-all approach. A dietitian can help you figure out meal and snack strategies to help you succeed in your sport and avoid developing RED-S.
- Rest & Recovery. It is so important to give your body the rest it needs. The body is not a machine, and it requires adequate rest to repair and rebuild!
Link to the Screening Tool Information:
Start your journey to a
Healthier Tomorrow
Meet Sara and Sabrina. Their team is here to answer your questions and help you find the right Healthier Tomorrows dietitian. After requesting an appointment, someone from their team will follow up with you.
Schedule an Appointment Online Submit Scheduling FormSubmit Scheduling Form
Fill out our scheduling form below. Our team will reach out to you to help you find the right Healthier Tomorrows dietitian.