What Every Active Female (and Male) Should Know about Low Energy Availability and RED-S.

By Lexi Moriarty, MS, RD, CSSD & Ashley Dimon, Sports Nutrition Volunteer

Depending on your circles, you may have heard these terms thrown around or even whispers about them around the internet, but you may not be sure exactly what it means. So I want to take a few minutes to break it down for you here! Here are the top 5 things that EVERY active female (and male too!) should know about low energy availability (LEA) and relative energy deficiency in sport (RED-S).

What is it?

Energy availability simply refers to how much energy (or calories) is being brought into the body and if it’s enough to manage everything the body needs to do on a daily basis, like keep physiological processes going, activities of daily living, and exercise. LEA or RED-S occurs when there’s not enough energy (or calories) being taken in to meet the body’s daily energy needs on a consistent daily basis.

To understand RED-S, we need to first remember the female athlete triad. The female athlete triad consists of three components: low energy availability, menstrual dysfunction and low bone mineral density. It refers to the interrelationship of low energy in the system, irregular or missing menstrual cycles, and the their resulting impacts on bone health.

The female athlete triad is so so important for active females to be aware of, BUT it completely leaves out two very important things. The first is that, bone health and reproduction (or menstrual cycles) are NOT the only systems effected by LEA. Second is that very similar variety of consequences can ALSO occur in males where this occurs. Enter RED-S or the term low energy availability (LEA), which encompasses ALL OF THE health and performance consequences that come along with this energy imbalance.

Who Does it Apply to?

Although research on RED-S and the female athlete triad mainly includes athletes, the concept of low energy availability (LEA) can very much apply to all females and males, active or not active, who simply aren’t eating enough. The important thing to remember is that this can be going on for a variety of reasons and does not always occur with disordered eating, although disordered eating tendencies are common in LEA. Some of the most common reasons for LEA other than disordered eating or an active eating disorder include low priority of eating, busy schedule with limited time to eat or availability of food, history of disordered eating, low body fat, lack of knowledge, high levels of training/exercise, and/or a mismanaged weight loss program.

Hormone & Bone Implications

One of the most common and serious implications of LEA is its impact on hormone health, which can occur in both women and men. As a result of LEA, women tend to experience irregular or missing periods, whereas men will experience symptoms of low testosterone.

While menstrual dysfunction, also known as amenorrhea, oligomenorrhea, or missing/irregular periods, isn’t uncommon in women, most women aren’t aware of its connection to LEA. A regular period is defined as cycles that come within 21 to 35 days of each other and ideally should last a minimum of 3-4 days. When there is less calories available to the body for energy, the body will skimp on the energy it puts towards systems, like reproduction, that aren’t seen as necessary for daily survival. For females, this almost always means their menstrual cycle and fertility will be impacted. Irregular periods can occur in as many as 60% of recreational athletes and up to 65% of athletes in some sports, especially those that idolize thinness like running, gymnastics, and dance.

The hormone levels in men can also be impacted by LEA resulting in low testosterone levels. Both menstrual irregularities and low testosterone levels have been linked to low bone mineral density in males and females. This can lead to increased risk for injury and osteoporosis (softening of the bone) at a young age.

There is of course other causes of irregular periods, hormone imbalances, and low testosterone other than LEA and there is currently no definitive test to identify when LEA is the cause. Unfortunately, through both personal experience and hearing my clients’ experiences, I find that doctors don’t discuss the potential of LEA enough with their patients. However it’s important to note that this is also a very new and developing area of research.

Other Signs & Symptoms to Look Out For:

Although hormonal changes are often the most noticeable effects of LEA, it can effect a lot of other systems too. Your body wants to do anything that it can to survive on a day to day basis, so if there is less energy available for survival it will prioritize high priority systems, like the heart, brain, and lungs, above all else. As a result, other systems, like hair, nails, skin, immunity, optimal cognition, digestion, will have less energy for use. Check out a few of the health and performance consequences below that were found during the more recent RED-S studies.

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How’s It Diagnosed:

At this time, the best way to identify LEA as a factor in abnormal menstruation, low testosterone or other questionable symptoms is by process of elimination. It’s important to rule out specific medical conditions and vitamin/mineral deficiencies early on in the process of investigating RED-S and LEA.

However, dietary and lifestyle changes to address LEA are often easy and risk free. If you think energy availability issues are a concern for you, a nutrition assessment by a Registered Dietitian, ideally a Certified Sports Dietitian (look for the CSSD) who is uniquely trained in this area, can be an easy next step to help you get your health and performance back on track.

References:

Mountjoy M, Sundgot-Borgen J, Burke L, Ackerman KE, Blauwet C, Constantini N, Lebrun C, Lundy B, Melin A, Meyer N, Sherman R, Tenforde AS, Klungland Torstveit M, Budgett R. International Olympic Committee (IOC) Consensus Statement on Relative Energy Deficiency in Sport (RED-S): 2018 Update. International Journal of Sport Nutrition and Exercise Metabolism. 2018; 28:316-331.
Mountjoy M. Relative Energy Deficiency in Sport Clinical Approach in the
Aquatic Disciplines. Aspetar Sports Medicine Journal. 2020;9:414-419