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The concept of energy availability is, in my opinion, one of the fundaments of sports nutrition’s appreciation of how to fuel an athlete.

There are situations in sports where the total caloric intake (the energy derived from the food we eat) is inferior to the total caloric expenditure (the energy we burn throughout the day). This might be due to high exercise energy expenditure and/or inadequate energy intake. This phenomenon, known as low energy availability, might occur consciously (to reduce body mass in order to improve performance or for aesthetics purposes) or inadvertently (lack of knowledge or physical difficulty to assume the correct amount of calories). Athletes who experience inadequate or low energy availability might negatively be concerned in terms of health and performance, especially if prolonged over time.

To correctly define this term, energy availability is the energy remaining for the physiological processes to take place, once the cost of exercise has been removed from the daily energy expenditure equation. In other words, it is the energy available for physiological functions once exercise energy expenditure has been removed from the total daily energy expenditure. Indeed, the body switches off those physiological processes that are not essential for survival, such as reproduction, the maintenance of bone mineral density and the immune system.

So what? Ensuring adequate energy availability through nutrition is key to supporting short- and long-term health and performance. Therefore, athletes need to understand their energy demands and properly fuel their bodies. Furthermore, an athlete’s entourage, including coaches, parents and friends, should be made aware of the risk factors linked with low energy availability. Prevention and early identification, which might be encouraged by sports nutritionists and exercise scientists might limit performance decrease and promote healthy bodies and minds in athletes.

References

• Logue et al. (2020): Low energy availability in athletes 2020: an updated narrative review of prevalence, risk, within-day energy balance, knowledge, and impact on sports performance. Nutrients [Online], 12 (3). Available on: https://www.mdpi.com/2072-6643/12/3/835/htm
• Mountjoy et al. (2014): The IOC consensus statement: beyond the Female Athlete Triad – Relative Energy Deficiency in Sport (RED-S). British Journal of Sports Medicine [Online], 48. Available on: https://bjsm.bmj.com/content/48/7/491
• Shirley et al. (2022): A life history perspective on athletes with low energy availability. Sports Medicine [Online], 52 (6). Available on: https://pubmed.ncbi.nlm.nih.gov/35113390/