Understanding Relative Energy Deficiency in Sport (RED-S): Definition and Causes

In this two-part series, UT Health Austin clinicians discuss the importance of adequate caloric intake for young athletes

Reviewed by J. Mica Guzman, Jr., MD, MBA, DABFM, CAQSM; Mia Roldan, LCSW, LCDC; Akua Afriyie-Gray, MD, FACOG; Lizette Taboada, RD, LD

Written by Lauren Schneider

A young woman is seen sprinting from above in the bright sun.  She has dark brown hair, and is wearing a black top with purple leggings.  The sun casts a long shadow of her running.

In recent years, high-profile athletes have opened up about their experiences with Relative Energy Deficiency in Sport (RED-S), a health condition which arises when a person’s caloric energy intake is insufficient for their level of physical activity. While much of this coverage centers on elite female athletes, RED-S impacts athletes at all sporting levels, regardless of sex.

Defining RED-S and the triads

The term “female athlete triad”, first used in 1992, originally referred strictly to female patients presenting with an eating disorder, amenorrhea (absence of menstruation), and osteoporosis (weakening of bones). In 2007, this definition was recognized to involve any large deficit in caloric intake relative to output, regardless of whether the patient displays disordered eating patterns.

This focus on available caloric energy rather than disordered eating behaviors has marked subsequent attempts to define the condition. The International Olympic Committee coined the term Relative Energy Deficiency in Sport (RED-S) in 2014 to encompass health problems resulting from caloric deficit in athletes regardless of sex.

In 2017, the male athlete triad was characterized by the Female and Male Athlete Triad Coalition as the unique clinical profile associated with RED-S in young men. Along with an energy deficiency and low bone mineral density, their definition included the decreased production of sex hormones.

Patients do not have to present every symptom of the male or female athlete triad to be treated for RED-S, says J. Mica Guzman, MD, a family medicine specialist who serves as the Primary Care Clinical Director of the Sports and Injury Clinic within the Musculoskeletal Institute at UT Health Austin.

Dr. Guzman describes RED-S as “an umbrella that is thought to have at its core the low energy Intake or excessive energy expenditure, which then leads into a myriad of [problems with] effective metabolism, menstrual function, bone health immunity, protein synthesis, and mental health.”

High energy demands of intensive sports

According to Mia Roldan, LCSW, even when young athletes do not have an eating disorder, they may not recognize that it is normal to supplement intensive exercise with a higher caloric intake. Roldan is a social worker in the Integrated Behavioral Health care team at UT Health Austin as well as through UT Health Austin’s Pediatric Psychiatry at Dell Children’s, a clinical partnership between Dell Children’s Medical Center and UT Health Austin.

She attributes some of this caloric deficit to the demanding schedules of young athletes, stating that long practices on top of a full school day leave little time for proper nutrition.

Additional risk of eating disorders among athletes

In addition to athletes not eating enough to compensate for energy expended during exercise, many athletes do develop disordered eating patterns, which Roldan says often result from the “hyper-focus on one’s body” inherent to any sport.

This focus “can trigger disordered eating thoughts and behaviors in adolescents already struggling with body image concerns.”

In other cases, these patterns start as a desire to eat healthy to improve athletic performance, says Lizette Taboada, RD, a registered dietitian who serves at the Musculoskeletal Institute and Women’s Health, a clinical partnership between Ascension Seton and UT Health Austin. Taboada is the Nutrition and Behavior Change Lead on UT Health Austin’s Integrated Behavioral Health care team.

“If an athlete begins to feel pressure, they can start to restrict their diet by eliminating food groups and/or lowering their calorie intake. This can lead to an eating disorder,” Taboada warns.

A University of Wisconsin survey of over 300 girls involved in high school sports during the 2006-2007 season found that more than a third of participants reported disordered eating behaviors like skipping meals, purging, or abusing diet pills. These behaviors were reported by over forty percent of respondents in sports with an aesthetic focus, such as gymnastics.

While eating disorders are traditionally associated with young women, any athlete can develop disordered eating patterns. According to the National Eating Disorders Association, this is especially true in sports like wrestling where athletes are sorted into weight classes.

What to know

Sports and exercise have important physical, social, and emotional benefits for children and teenagers, but sustainability is key. Growing athletes need adequate fuel to power both their development and their performance on the field.

Many young athletes do not consume enough calories to match their high energy exertion; this challenge is often compounded by the body image issues that many adolescents experience. This improper nutrition can result in long-term health problems. The second installment of this series will explore health complications associated with RED-S as well as the approach UT Health Austin practitioners take in treating the condition.

About UT Health Austin

UT Health Austin is the clinical practice of the Dell Medical School at The University of Texas at Austin. We collaborate with our colleagues at the Dell Medical School and The University of Texas at Austin to utilize the latest research, diagnostic, and treatment techniques, allowing us to provide patients with an unparalleled quality of care. Our experienced healthcare professionals deliver personalized, whole-person care of uncompromising quality and treat each patient as an individual with unique circumstances, priorities, and beliefs. Working directly with you, your care team creates an individualized care plan to help you reach the goals that matter most to you — in the care room and beyond. For more information, call us at 1-833-UT-CARES or request an appointment here.

About the Partnership Between UT Health Austin and Dell Children’s Medical Center

The collaboration between UT Health Austin and Dell Children’s Medical Center brings together medical professionals, medical school learners, and researchers who are all part of the integrated mission of transforming healthcare delivery and redesigning the academic health environment to better serve society. This collaboration allows highly specialized providers who are at the forefront of the latest research, diagnostic, and technological developments to build an integrated system of care that is a collaborative resource for clinicians and their patients.

About the Partnership Between UT Health Austin and Ascension Seton

The collaboration between UT Health Austin and Ascension brings together medical professionals, medical school learners, and researchers who are all part of the integrated mission of transforming healthcare delivery and redesigning the academic health environment to better serve society. This collaboration allows highly specialized providers who are at the forefront of the latest research, diagnostic, and technological developments to build an integrated system of care that is a collaborative resource for clinicians and their patients.