Athlete Health: About Relative Energy Deficiency

Soccer is one of the most demanding sports in athletics. It’s a rewarding sport, but it takes a lot of physical and mental fortitude.

Sports that require heavy physical demands also require adequate fuel and rest. There’s only so much the body can take before warning signs appear.

The minor consequences of inadequate fuel and recovery are symptoms of overtraining like excessive fatigue and poor performance.

If those symptoms go unaddressed, the next consequence is relative energy deficiency in sport (RED-S). Prolonged RED-S can cause irreparable damage to the athlete.

Unfortunately, true RED-S is common enough that it should be on the coaches’ and parents’ radar with young players aspiring to be elite.

This topic is almost never brought up until it’s an issue. But what’s the use in that?!


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About Relative Energy Deficiency

RED-S is a new term that has replaced Female Athlete Triad to also include male athletes.

This condition describes low energy availability in all athletes.

Sure, athletes get tired and need rest. However, this condition tends to refer to chronically low energy that has started to affect bodily systems like the:

  • Reproductive system
  • Hormonal systems
  • Skeletal system
  • Musculoskeletal system
  • Immune system

What Causes RED-S?

Prolonged energy imbalance causes RED-S. Energy imbalance refers to excessive energy output compared to energy availability.

Inadequate recovery and nutrition are catalysts to RED-S. The most infamous reason for RED-S is inadequate nutrition.

Sometimes this is unintentional, often seen with picky eaters.

There are also times where this is intentional, often seen with disordered or restricted eating. This is common in athletes with perfectionist personalities. Gymnasts, dancers, and wrestling/MMA have the most pressure to fit a physical mold, so disordered eating is most often seen in those sports. (2)

However, disordered or restricted eating is also seen often in soccer, swimming, and other physically demanding sports where body image is often judged.

What Are the Symptoms of RED-S?

Early signs that an athlete is heading into relative energy deficiency are similar to that of overtraining. If those signs aren’t caught or addressed, it could evolve into RED-S.

Those who are most likely to develop RED-S may have or experience: (2)

  • Restricted eating
  • Frequent injuries
  • Frequent sickness
  • Irregular or no menstrual cycle

Frequent injury and sickness are signs that may be more obvious to an athlete or player. However, it’s hard to know how to define restricted eating or menstrual cycle regularity.

Restricted eating to a strict caloric intake per day can be dangerous for an athlete. One of the most commonly restricted nutrients among female athletes are carbohydrates, which are critical for energy availability. (1)

Irregular or no menstrual cycle highly depends on the female athlete. Some experience a heavy cycle one month and a light cycle the next, which is normal for them. Others have not had their menstrual cycle yet.

It is considered abnormal if the female athlete: (2)

  • Has not had a period by age 16
  • Has not had a period in >6 months

These are signs to talk to a medical professional.

What are the consequences of untreated RED-S?

Untreated RED-S can lead to an array of systemic issues, some of which are difficult to reverse, if possible. This includes: (4)

  • early-onset osteoporosis and subsequent bone fractures
  • reproductive issues later in life
  • damaged organs
  • cardiovascular dysfunction

Treatment of RED-S usually requires a multidisciplinary approach. A doctor or pediatrician may refer you to a nutritionist, psychologist, endocrinologist, or any other professional that can help address the condition.

3 Ways to Prevent Energy Deficiency

1. Watch Training Volume

Keep track of sport participation. How many hours are you training? Are you exceeding 20 hours per week as recommended by US Youth Soccer?

If you are, make sure you consult with a pediatrician who understands young athletes and can provide you with the right resources to stay healthy during many hours of training.

2. Incorporate Rest Days and Prioritize Sleep

Sleep is the most important recovery tool, way above all the products and supplements out there. Make sure you rest and recover just as seriously as you train.

3. Eat Right and Watch Out For Self-Restricted Diets

If you’re considering a specific diet, make sure you talk to a health professional first. Otherwise, divulge in various complex and simple carbs, proteins, fats, vitamins and minerals to fuel the body.

4. Don’t Compare Your Body to Others

Athletes are competitive in nature. Don’t let that competition drive unhealthy fixations on physical aesthetic.

Lighter does not always mean faster. Skinnier does not always mean healthier. Muscular does not always mean strong (it’s true).

Every body functions optimally at different body compositions, so it’s impossible to really compare your body to another’s.

Stay Healthy Out There

Signs and symptoms of overtraining and relative energy deficiency are easy to miss.

If you are a parent, keep an eye on your player’s diet and encourage eating a variety of foods to receive adequate nutrients. Take steps to ensure they receive the guidance needed with high training volume. Create a safe space to discuss physical and mental burdens that your player may be experiencing so that you can both monitor health together.

If you are an athlete, remember that your body is strong and capable when you fuel it appropriately and prioritize sleep. Speak up if you notice frequent aches and pains, excessive fatigue during the day, or if your period has been a bit off (females).


  1. de Borja, C., Holtzman, B., McCall, L.M. et al. Specific dietary practices in female athletes and their association with positive screening for disordered eating. J Eat Disord 9, 50 (2021).
  2. Dudgeon, E. (2019, April 22). Relative energy deficiency in sport (red-S): Recognition and next steps. BJSM blog – social media’s leading SEM voice.
  3. Kuikman, M. A., Mountjoy, M., Stellingwerff, T., & Burr, J. F. (2021). A Review of Nonpharmacological Strategies in the Treatment of Relative Energy Deficiency in Sport, International Journal of Sport Nutrition and Exercise Metabolism31(3), 268-275.
  4. Thein-Nissenbaum, J. (2013). Long term consequences of the female athlete triad. Maturitas75(2), 107-112.

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