Relative energy Deficiency in Sports

energy deficiency female athlete triad sports nutrition Apr 26, 2023

Ken Roberts, MA, RD, LDN


Relative Energy Deficiency in Sport (RED-S) used to be referred to as the Female Athlete Triad. But, before you scroll away, understand that this change of name implies that this syndrome affects more than just females.


The female athlete triad or just (the triad) refers to three clinical entities that include menstrual dysfunction, low energy availability (with or without an eating disorder) and decrease bone mineral density (BMD).

If you're a female, and you have a regular menses, you're likely thinking this doesn't affect me either. But, RED-S still does.

If you're a male, you immediately dismiss this as not affecting you, because're not a female. True the triad doesn't, but RED-S does.

Let's get specific with all genders: male, female, and gender neutral or transitioning genders. RED-S affects you all.


RED-S describe a syndrome of poor health and declining athletic performance that happens when athletes (even recreational athletes) do not get enough energy available. This energy imbalance may be intentional or by accident from intense exercise, frequent exercise, or by not eating enough.


Athletes with low-energy availability (LEA) are 2.4 times as likely to have psychological disorders, such as irritability, depression, impaired judgement, and decreased coordination and concentration.

We're not talking about laying in bed all day depressed, or driving while intoxicated levels of impaired judgement or decreased coordination. This can manifest in different ways, such as lower focus, lower motivation, lower sex drive, difficulty hitting the same paces or weights.


Your body as an athlete has narrative. A story it communicates to you. When you do not eat enough, the body suffers, and it speaks to you through symptoms. Some symptoms you may experience from LEA include:


Gastrointestinal - Upset stomach, diarrhea, bloating, abdominal pain, constipation and bloating. You can't tolerate anything before practice or training. It's hard to eat after training. When you eat certain foods your stomach gets upset.

Metabolism - Increased hunger, weight gain, and low energy levels. You're cold often, even in the summers. You exercise and eat well, but still feel like you're gaining weight.

Immunity - Frequently ill, take longer time to recovery, increased inflammation in the body

Hormones - Lab levels such as vitamins or thyroid can run low. Also higher risk for diabetes. Males might experience lower testosterone.

Performance - Your perceived rate of exertion is higher from lighter efforts, your recovery is longer, and fatigue faster.

Mental Health - Irritability, upset, nervous or anxious, depressed, and difficulty focusing. If you don't exercise you feel weird. You wake up frequently at night with restless thoughts. You think about food frequently.

Menstrual Function & Sexual Function - Endurance athletes typically have low testosterone? You're male and don't get erections in the morning. You stopped having your menses, but were told that's normal for athletes.

Bone Health - Decrease energy and minerals effects hormones which can lead to frequent injuries and low bone mineral density. This can lead to fractures of the bones.

Cardiac - Your heart rate goes up fast when you start exercising. You get dizzy when you stand up too fast. Your heart rate is too low. Your heart rate is less variable.


It does not matter if you're male or female, or gender fluid. If you're not eating enough to support your body's daily needs AND your training needs you are under-fueling (low energy availability).


How do you avoid these symptoms of RED-S, and fuel your body correctly? By finding the sweet spot. To start we identify what your Available Energy (EA) needs are. This is the amount of energy needed to support fueling (feeding with calories) your lean body mass (LBM), your daily activities, and exercise. The most accurate way to start this is to have your body fat tested, and determine what your lean body mass is and your body fat mass. You can then determine your EA.


Here's the formula you can use to determine your EA.

EA = (Energy Intake - Energy Expenditure) / Lean Body Mass.


Once we know our EA we can then determine our Sweet Spot for Fueling. The Sweet Spot is going to be a range that is different between men and women, their exercise activity, age, and training status. Which is why we build in range to start with then, and then dial in what is best for the athlete. Fueling the sweet spot is very different than other recommendations which focus on weight loss by factoring in the total body weight. Here we are only focusing on fueling our lean body mass and the energy it takes to maintain it, move it around through the day, and the stress we put on it during training and exercise. What are we not fueling? Body Fat. The range for men and women takes body fat into consideration, and we can optimally fuel in the sweet spot to support our training, and have our body fat come down at the same time. BUT, if we under eat we will be in an energy deficit state (LEA). Recall when that happens for too long all those symptoms in the athlete narrative occur.

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