Nutritional considerations for RED-S

More and more athletes are falling into the pitfalls of Relative Energy Deficiency in Sports (RED-S). RED-S has evolved out of what is known as the ‘female athlete triad’ – menstrual dysfunction, disordered eating and osteoporosis, with low energy availability considered to be the most important contributory factor.

This triad is now regarded part of RED-S, a far broader syndrome that affects many areas of an athlete’s physiological function, health and performance. It is also recognised that RED-S can affect both male and female athletes.

RED-S is essentially the failure to synchronise an athlete’s nutritional intake with the energy demands of their daily living, growth and training loads. Although it can affect any athlete of any age in any sport, RED-S is more prevalent in weight-making (e.g. judo and boxing) and aesthetic sports (e.g. figure ice-skating and gymnastics), as well as sports where having a lower body weight benefits physical performance (e.g. long-distance running and cycling).

This mismatch between an athlete’s nutritional intake and their training does not only affect bone health and hormonal balance (and, therefore, menstrual function) as commonly described in the female athlete triad. There is a myriad of adverse consequences that also affect an athlete’s immune system, metabolic health, gut health, neuromuscular function, cardiovascular system, psychological health, etc. (Figure 1).

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Figure 1 – Adverse health effects of RED-S. *Psychological consequences can either precede RED-S or be the result of RED-S (from the Consensus Statement).

It’s encouraging to see RED-s being described in this way by mainstream sports nutrition, exercise science and medicine because this encompasses an integrative and body-systems approach. It resembles functional medicine’s spider web model (Figure 2): if one area of an athlete’s health is imbalanced (the web is damaged), this will probably have subsequent effects in other systems. And, ultimately, if an athlete’s health is adversely affected, their performance is also very likely to suffer no matter how much training they do, with an increased risk of injury and infection (Figure 3).

The Web

Figure 2 – Functional Medicine – The Web


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Figure 3 – Potential adverse effects of performance as a result of RED-S. *Aerobic and anaerobic performance (from the Consensus Statement).

To avoid falling into the pitfalls of RED-S, it’s essential to ensure an adequate and well-balanced energy and macronutrient intake with a strong focus on food quality. I would also encourage the integration of more fermented foods in the athlete’s diet to support gut health.

Periodisation of their nutrition with training and recovery is also vital. An athlete’s energy intake is not a static thing. It should match their training load, especially in relation to carbohydrates, with more being consumed on heavier training days. It’s also important to take in most of the carbohydrates around the training session to use it as a fuel beforehand and to restore glycogen stores afterwards. This strategy will also help the athlete meet their energy intake goals.

I wouldn’t encourage a low-carbohydrate periodisation approach if an athlete isn’t meeting their energy intake requirements and is struggling with RED-S. RED-S has been shown to cause hormonal and metabolic disruptions and a lack of carbohydrates reduces glucose utilisation and the mobilisation of fat stores. It also slows down an athlete’s metabolic rate and decreases growth hormone production as discussed in the Consensus Statement. I would rather encourage an athlete to maintain a consistent intake of food throughout the day, i.e. similar amounts of food for breakfast, lunch and dinner with snacks between meals if needed. This strategy will also ensure that an athlete meets their energy intake goals and may help prevent any within-day energy deficits, i.e. time in a catabolic state, which a recent study has shown is associated with disturbances in metabolic and endocrine markers, such as decreased oestradiol and increased cortisol levels in female endurance athletes.

Lastly, it’s also vital to identify whether the athlete is showing any signs of disordered eating and is resisting the implementation of nutritional changes. In this case, I would encourage extra psychological support from a mental health specialist to address what issues around their food are impeding them from achieving an optimal energy intake.