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Relative Energy Deficiency in Sport

Energy availability is an important concept for athletes. It’s defined as the energy available to the body (from food) after the costs of exercise have been accounted for. When energy availability is below an important threshold level to support training and important bodily functions, this is known as Low energy availability.

During these times athletes expose themselves to a variety  of potential health and performance complications. Symptoms that occur through low energy availability were initially researched and identified in female athletes and were then part of a greater process known as the“female athlete triad”. However in recent years it has become apparent that this process effects males very similarly as well as many other processors in the body than those identified in the initial triad.  Hence this process has been renamed RED-S (relative energy deficiency in sport) to encompass all athletes and a greater range of symptoms. 


With the physical demands of significant exercise and the growing pressures athletes can be exposed to for achieving unrealistic body mass and body fat levels, energy availability can easily be compromised. Therefore a well planned and adequate diet is vital for optimal health and performance. Read below for more information. 

The syndrome of RED-S refers to ‘impaired physiological functioning caused by relative energy deficiency and includes, but is not limited to, impairments of metabolic rate, menstrual function, bone health, immunity, protein synthesis and cardiovascular health’. The underlying factor of this syndrome is caused by low energy availability (LEA). (1.) 

Low Energy Availability (LEA)

1 Mountjoy M, Sundgot-Borgen J, Burke L, et al. The IOC consensus statement: beyond the Female Athlete Triad – relative energy deficiency in sport (RED-S). Br J Sports Med 2014;48:491–7.

Signs & Symptoms of
Low Energy Availability

  • An increased occurrence of colds, flus and illness can be a sign of low energy availability. Also a constant feeling of fatigue and tiredness.

  • Stress fractures and frequent or reoccurring injuries may occur in athletes with low energy availability. Low energy availability has shown to cause irreversible bone loss in athletes.This is combined with the suppression of important metabolic hormones which promote bone formation. Long term bone health can  significantly be impaired and places athletes at risk for a higher incidence of stress fractures.

  • Certain female hormones can be reduced as a result of low energy availability, these can be measured as part of an assessment with your physician.

  • Irregular or absent menstrual cycles should be treated as a warning sign for low energy availability.Endurance sports has one of the highest prevalence of menstrual disorders. Reproductive development and function can be significantly impaired by low energy availability.

  • Certain female hormones can be reduced as a result of low energy availability, these can be measured as part of an assessment with your physician.

  • There is growing evidence that males may experience low energy
    availability and resulting health consequences of RED-S.
    With high risk sports including cyclists, rowers, runners, jockeys
    and athletes in weight class combat sports.

  • While RED-S may occur in both sexes, there are likely differences in biological responses to LEA in male athletes.
    The threshold and duration of the LEA state required to induce RED-S in men is unknown compared to woman. Reduction
    in the sex hormone testosterone is
    likely to be of greater
    health concern in male

Recommendations to optimize your energy availability 

Avoid severe weight loss regimes
 If weight loss is desired it is vital to plan this appropriately with a sports nutrition professional. Weight loss needs to be achieved at a recommended pace to avoid the health consequences of low energy availability. Low energy  intakes on highly active training days can cause significant energy deficiency and over time can lead to RED-S.

Be aware of the energy costs of training
This will vary throughout the year depending on training loads and intensities. Adjust your energy intake accordingly during these times. A periodised nutrition plan is essential for serious athletes to enhance training adaptation but also ensure optimal recovery and maintaining health. A basic nutrition plan following the same thing every day is inadequate to maintain energy availability in those who are seriously active. 

Strongly consider and plan accordingly for significant changes in diet and lifestyle. 
 Before starting a new diet or following a certain lifestyle consider how this may effect your energy availability. Currently most public nutrition messages are based on reducing energy intake due to the growing numbers of obese within the population. Diets based on removing or reducing certain food groups can significantly reduce your energy intake. Whilst severe energy restriction can have positive outcomes for those who are obese due to weight loss and positive metabolic outcomes, this can have negative consequences for those active individuals who do not maintain appropriate levels of energy availability. 

Ensure energy availability is appropriate around vital training sessions
 More and more research is showing improved exercise performance, recovery and hormonal response when energy is matched accordingly to the training requirements. This can be termed "fuel for the work required", it means if quality training takes place in the morning, energy intake is prioritised before and after these sessions. Whilst some elite endurance athletes may complete  some lower intensity sessions with restricted nutrients to maximize stress and adaptation, it is vital that high quality sessions are completed with high energy availability. Overall health and immune status needs to be thoroughly assessed before training with low energy is considered.  

Get your periodised and individualised plan now from Dane Baker Nutrition
Plans are unique to you, they are periodised across the week to ensure energy availability is matched for specific training days. Energy is then calculated for your goals, whether they be gradual weight loss whilst still maintaining performance, weight maintenance or muscle gain. This plan will provide a significant blue print to optimise recovery, adaptation and overall health. However optimisng energy availability is a continual moving process, further follow up will allow for fine tuning for the goal to reach your ideal energy availability. 

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