Undernutrition: the strong road to recovery

In most sports, the body is moved through space, and being able to move the body through space with greater speed is almost always a performance advantage. This is particularly true in endurance sports where athletes must cover large distances in as little time as possible. Doing so depends on two factors: the ability to create large amounts of force and the ability to keep body mass as low as possible. The more force athletes can create over time, the faster they’ll go, and the less mass they have to move with that force, the faster they’ll go.

Training, nutrition and RED-S

To optimize performance, endurance athletes undertake large volumes of training to develop the physiological resources to produce large amounts of energy to power their efforts. The more energy they can create and sustain, they better their performances will be, and high training loads support the development of these abilities. At the same time, many athletes will attempt to work on the other side of the equation, controlling or limiting energy intake in the attempt to reduce body mass or maintain it at an optimally low level.

When energy expenditure significantly exceeds energy intake, athletes experience low energy availability. In other words, because they are expending a lot of energy through training, while consuming insufficient energy through their diet, they create a significant negative energy balance.  Unfortunately, when low energy availability is present for extended periods of time, it can lead to many negative health and performance outcomes, which we’ll discuss shortly. These are collectively known as ‘Relative Energy Deficiency Syndrome’ or RED-S for short.

Of course, RED-S is not limited exclusively to endurance athletes. Any athlete with high exercise energy expenditures due to a high training volume is potentially at risk. Likewise, any athlete that is voluntarily entering a caloric deficit (to lose a significant amount of weight) is also at risk, regardless of their sport. And certainly, those risks go up when both factors are present. It’s all about energy balance and maintaining an optimal relationship between energy expenditure and energy intake. Whenever one or both sides of the equation significantly deviate from the norm, negative consequences can ensue. As such, it’s an issue that can impact any individual involved in sport. And with high training volumes and energy restricted diets present throughout sport, it does impact many individuals.

Unfortunately however, much of the focus remains on the positive benefits of high training volumes and energy restrictive diets, with little attention given to the risk of negative outcomes. While these strategies undoubtedly can be beneficial, failure to acknowledge the risks can lead to outcomes that are opposite of the intended ones. An understanding of the potential risks of RED-S, as well as strategies to combat the negative impacts of RED-S is critical for both long-term athlete health and long-term performance.