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Relative Energy Deficiency in Sport (RED-S) in Female Athletes

What You Need to Know from our Dietitian, Allyson Balzuweit RDN/LD

What is RED-S

Physically active people, and young females in particular, are at risk for an often unrecognized disorder called Relative Energy Deficiency in Sport (RED-S). The concept of RED-S stems from an earlier diagnosis called “The Female Athlete Triangle”, which emerged in the 1990s and had a more narrow focus. In 2014, the International Olympic Committee coined the new term RED-S.

RED-S is typically characterized by insufficient caloric intake (with or without disordered eating patterns), lack of menstrual cycles (known as amenorrhea) and low bone density.

When there’s too large of a gap between energy expenditure and caloric intake in menstruating females, estrogen levels decrease which causes periods to stop. This drop in estrogen also causes bones to become more porous, which can lead to stress fractures as well as osteoporosis over time.

Who is at risk?

While any physically active person is at risk for RED-S, competitive and elite athletes are at higher risk compared to someone that is exercising on a more casual or recreational level. Endurance sports like cross-country running, as well as those that have an aesthetic element with uniforms that are tight fitting (think ballet, gymnastics and swimming) also tend to add a level of risk.

Performance and RED-S

Lack of proper fuel will weaken the performance of any athlete, even when this is an unintentional behavior. Initial symptoms can present as early fatigue, but as time goes on, muscle size and strength can decrease. Essential bodily functions like breathing and heart rhythm rely on energy from skeletal muscle. Strength loss leads to injuries and these injuries tend to be slower to heal due to the nature of insufficient fuel. And the cycle continues.

The loss of menstruation mentioned above impacts hormone balance. Lower estrogen levels trigger bone loss, and repeated stress fractures are a red flag that diet and exercise patterns should be immediately addressed, as bone loss that occurs from amenorrhea can be irreversible.

Oftentimes the symptoms of RED-S go unnoticed at first, because they are all relatively mild on their own (and therefore don’t even get recognized as symptoms. Another danger is the fact that some of the symptoms are perceived as part of the challenge of a particular sport. In the short term, lack of menstruation (less cramps and inconvenience), lower body weight and improved performance can actually be a welcomed relief but instead should be a red flag.

Here are some things to be on the lookout for…

Physical Warning Signs of RED-S

  • Amenorrhea (loss of periods)

  • Chronic coughs and colds

  • Gastrointestinal Issues

  • Sensitivity to cold

  • Stress Fractures

  • Muscle cramping and weakness

  • Dental problems

Psychological Warning Signs of RED-S

  • Over Exercising

  • Avoidance of eating in some situations

  • Lack of focus

  • Preoccupation with weight

  • Anxiety/Depression


Fortunately, there are several ways to prevent RED-S from becoming a problem.

  • Choosing sports that naturally complement individual ability and natural body strengths will help to ensure a better fit for the type of exercise that’s being considered.

  • Prioritizing health over performance/appearance is a fundamental yet often overlooked component to maintaining good health and energy.

  • Avoiding frequent using the scale, which can even subconsciously contribute to eating disordered behaviors and/or thoughts.

Nutrition Guidelines

Focusing on food as fuel and minimizing the focus of food in relation to body size/shape is a more positive way to view the relationship between eating and exercise performance.

Carbohydrates and Protein rich foods are an essential part of a healthy training diet. While carbohydrates are the main source of energy to fuel performance during exercise, protein is critical for building and repairing muscle.

A good rule of thumb for athletes is to include 30 to 35 grams of protein with each meal (the equivalent of a 5 oz. chicken breast), and 30-45 grams of carbohydrate, which might look like a small to medium sweet potato, 2/3 cups of brown rice or ¾ cup cooked quinoa. Healthy sources of fat are also necessary to facilitate digestion and help with nutrient absorption. 15-20 grams per meal is a good range for most athletes.

Both protein and carbs can be found in different food groups. For example, a container of Greek yogurt will provide 15 or so grams of protein and 7 or more grams of carbohydrate. It can feel a little bit tricky, but choosing nutrient dense options for carbs and protein is very important!

Here are some examples of what to include on a regular basis as part of a healthy meal plan. This is not an exclusive list, but can certainly point you in the right direction.

Carbohydrate sources:

Whole grain or sprouted bread, tortillas, crackers

Quinoa (also provides more protein compared to other carb sources)

Sweet Potatoes


Brown rice

Lentil or garbanzo bean pasta (for added protein and fiber)

Legumes (black beans, lentils, chickpeas)

Protein Sources:


Grass fed beef

Wild salmon

Canned wild tuna, salmon and chicken

Plain or lightly sweetened Greek yogurt

Grass fed meat sticks (Chomps)

Edamame / Tofu / Tempeh

Hemp hearts

Chia seeds

Healthy Fat Sources:


Olives and olive oil

Nuts and seeds

Nut and seed butters

Chia seeds

Hemp hearts

Grass fed dairy

Fatty fish (salmon, tuna, sardines, anchovies)

Consulting with a Registered Dietitian for personalized recommendations can be a critical piece to ensure that all athletes are properly fueling to support energy needs, body functions and to preserve muscle mass and bone density. A personalized plan that is customized to consider all aspects of health and fitness will make a big impact on both performance and health.

For more information or to schedule a consultation, feel free to contact me in one of the following ways.

Phone: 678-575-3413

Thanks for reading!

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