What is Relative Energy Deficiency in Sport (RED-S)?

BY: Katherine Schaumberg, PhD

DATE: 6 April 2017

Originally termed the female athlete triad and more recently updated to include additional psychological and physical components, Relative Energy Deficiency in Sport (RED-S) is a condition that can affect athletes of any age and sex. RED-S occurs when an imbalance in energy intake and energy output has detrimental effects on bone health, menstrual function (in women), metabolic rate, immune function, cardiovascular health, and psychological health.


Figure from: Mountjoy et al. (2014)

How is RED-S different from eating disorders? RED-S may overlap with an eating disorder or serve as a risk factor for eating disorder onset, but not necessarily. Even when RED-S does not overlap with a typical eating disorder presentation, energy deficiency can cause major problems with physical and psychological health. One concern in those with RED-S is osteoporosis. Poor bone growth as a result of energy deficiency in young people can lead to stress fractures. In addition, individuals with REDS evidence increased risk for injury, decreased endurance, and reduced muscle strength, along with decreased coordination, impaired judgment, irritability, and depression. While athletes may believe that they will increase sport performance by reducing caloric intake and increasing their training schedule, the opposite occurs. Sport performance lags as available energy is at a premium. For athletes at all levels of sport participation, assessing intake needs and adjusting intake to meet the needs of training is vital. To achieve energy balance, increases in a training schedule along with normal growth and development require increasing energy intake.

Here are some things to remember when assessing whether your body is getting adequate intake (food) relative to output (exercise):

  1. Loss of menstruation is not a normal part of training; it is a red flag. While some women think that irregular or missed periods are a normal part of training for their sport, disruption of menstruation is a sign of energy deficiency. Irregular periods indicate that a person is likely to experience other elements of RED-S, including loss of bone density. Loss of menstruation can happen even when girls and women are not at a low weight.
  1. Increasing intake is necessary if a training program increases. In order to meet training needs, having regular meals and snacks is necessary. It may be necessary to add extra snacks throughout the day when a training schedule increases. Talk to a dietician to help you evaluate your energy needs.
  1. Too much exercise can be problematic. High levels of exercise can lead to high risk for injury. Bodies work well when they are active, and exercise has many benefits; however, bodies also need lots of rest. For individuals with an active eating disorder, vigorous exercise is discouraged, but overtraining can be problematic even for those who do not have an eating disorder.
  1. The “ideal body” portrayed in sports can be an unattainable standard. Some sports may have specific differences in how an “ideal” body type might be portrayed. For example, the “ideal” body portrayed for a gymnast is different from that of a tennis player. While there is often a presumption that that achieving a specific body type will result in improved performance, this is not the case. Different individuals have different body types as a result of their genes, even if they adhere to the similar training programs. Also, having a body that does not adhere to ‘typical’ standards for a sport does not preclude participation, enjoyment, improvement, and success in that sport. For many individuals, attempts to pursue a specific body ideal will decrease their sport performance as they experience energy deficiency.

The bottom line is that sports participation should be beneficial, not detrimental to your body. Correctly estimating and addressing energy needs is the single best way to equip your body for the rigors of training.


Mountjoy, M., Sundgot-Borgen, J., Burke, L., Carter, S., Constantini, N., Lebrun, C., . . . Ljungqvist, A. (2014). The IOC consensus statement: beyond the Female Athlete Triad–Relative Energy Deficiency in Sport (RED-S). Br J Sports Med, 48(7), 491-497. doi:10.1136/bjsports-2014-093502

Slater, J., Brown, R., McLay-Cooke, R., & Black, K. (2017). Low Energy Availability in Exercising Women: Historical Perspectives and Future Directions. Sports Med, 47(2), 207-220. doi:10.1007/s40279-016-0583-0

Stewart, T. M., Plasencia, M., Han, H., Jackson, H., & Becker, C. B. (2014). Moderators and Predictors of Response to Eating Disorder Risk Factor Reduction Programs in Collegiate Female Athletes. Psychol Sport Exerc, 15(6), 713-720. doi:10.1016/j.psychsport.2014.02.006