Relative Energy Deficiency in Sport

Learn about the health and performance impacts of relative energy deficiency in sport (RED-S) as well as key strategies for RED-S treatment.
relative energy deficiency in sport

It’s no secret that the energy needs of athletes are typically higher than those of their non-athlete peers. However, it isn’t uncommon for us to find in our 1-on-1 sessions that athletes often do not eat enough to keep up with the energy demands of their sport. Sometimes athletes intentionally undereat, especially in body conscious sports like running and gymnastics or weight class sports like wrestling and rowing. Other times, they underestimate how high their energy needs are or simply haven’t learned how to build adequate meals and snacks to carry them through a busy schedule . Regardless of the reason, athletes who do not meet their energy demands are at risk for relative energy deficiency in sport (RED-S). Read on to learn more about what RED-S is, its consequences, and how RED-S treatment can improve health and performance outcomes if you or an athlete you know is at risk.

What is RED-S?

It all started with the “female athlete triad”. This was a term used for three linked symptoms that occurred with overtraining and under-eating in female athletes: low energy availability, loss of periods or irregular periods, and decreased bone mineral density. 

When an athlete’s energy or food intake does not match their energy expended in training, it can lead to inadequate energy available to support basic bodily functions critical to overall health. This is known as low energy availability. Low energy availability can affect both male AND female athletes, and results in many more consequences than the three linked in the triad, so in 2014, the International Olympic Committee (IOC) introduced the more inclusive term “RED-S”.

Is RED-S an eating disorder?

It’s complicated, but not really. It can be a red flag for an eating disorder in some, but as mentioned, RED-S can definitely occur inadvertently and is quite common in the athletic population. And big disclaimer: you do not need to be incredibly lean or experience weight loss to have low energy availability. Student athletes have high energy needs that can be challenging to keep up with! On top of a busy class schedule, the toughest training yet, and the first time away from home for some, high school and even college athletes are still growing and developing. These all lead to high energy demands, and with a lack of awareness in sports-specific fueling, it can be really difficult to keep up with.

relative energy deficiency in sport

What are the warning signs?

RED-S ultimately affects athletes from both health and performance perspectives. Symptoms can vary amongst different athletes and may even feel like typical consequences of overtraining:

  • Fatigue
  • Recurring injuries (especially bone injury, such as a stress fracture)
  • Frequent illnesses, such as regular colds or stomach bugs
  • Loss of period or irregular periods
  • Decreased performance
  • Irritability, depression or other mood changes
  • Muscle and/or weight loss

Essentially, inadequate energy availability over time leads to a decreased ability to recover from training sessions. This can impact performance by making it difficult to bounce back for the next training session or competition. 

Even more important than performance are the short and long term health risks that can come with low energy availability over a long period of time. These can include osteoporosis, depression, reduced immune function, and reproductive issues. So as sports dietitians, when we see signs of RED-S in an athlete, we take action quickly.

How is RED-S diagnosed?

It takes a team of the right experts, including coaches, doctors, sports dietitians, athletic trainers and sports psychologists. At first, it may be worth it to dial back on training to determine whether symptoms are caused by overtraining or RED-S. Sometimes, physicians even recommend abstaining from exercise for some time. If symptoms persist, then a doctor can order blood work and other tests to assess hormone levels, bone density, and investigate changes in body composition. Different medical professionals can help determine causes of RED-S, whether it’s an eating disorder/disordered eating, lack of fueling knowledge for sport, and/or a disordered mentality towards body image or training.

What are the best strategies for RED-S treatment?

The recommended treatment for RED-S is increasing energy availability. However, this is complicated as energy needs can be so variable among day to day, making it difficult to determine what would ensure adequate energy intake. Think about your training schedule. Some days you may have two-a-days, other days are off days, others are competition days or light training days. And we can’t forget about activities that don’t revolve around your sport, like walking to classes, taking the dog out, gym class- basically anything you do that requires movement. These factors ALL need to be considered when determining energy needs because they all play a role in expending energy!

RED-S treatment involves one or both of the following: increasing energy intake and/or decreasing energy expenditure (aka decreasing training frequency and intensity). From a nutrition standpoint, increasing energy intake can be complex. A sports dietitian can identify ways to help individual athletes make small, manageable changes to their nutrition program that can make a big difference from both a health and performance perspective. These changes are highly individual to each athlete but often involve some of the following:

  • Slowly increasing meal sizes and incorporating sufficient snacks
  • Implementing solid recovery nutrition practices, such as the ones mentioned in our recent blog post
  • Brainstorming on ways to fuel around a packed schedule  
  • Advising on energy intake during training
  • Introducing bone-building foods and supplements like vitamin D and calcium when necessary
  • Managing stress

Bottom line:

Know the warning signs and that RED-S and eating disorders/disordered eating can affect athletes of all different shapes, sizes, sports, genders, and levels. If you or an athlete you know is struggling or exhibiting RED-S symptoms, our registered dietitians are here to help. This is a complex topic, but fueling adequately is crucial for meeting health and performance goals and certainly doesn’t need to be navigated alone.

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