part 1 “How can undereating impact my sporting performance?”

The following BASE Journal entry was written by Christen Christen-Lee Bezuidenhout. Christen is an Accredited Practicing Dietitian (APD) based in QLD and NNSW, Australia.

PLEASE NOTE: This Journal post comprehensively unpacks understanding RED-S, The Relationship Between Under-fuelling for Performance, Food Relationships, and Body Image Among Athletes in Competitive Sports. 

We have shared this journal in 2 parts

Part 1 - How can undereating impact my sporting performance?

Part 2 - I think my body image issues and difficulty with eating is impacting my sporting performance, what should I do?

We encourage reading both journals in order at your own pace. 

As someone who has always loved sports and athletics, I understand the dedication and discipline that comes with being a young athlete. Growing up, I competed in athletics - particularly long-distance running, as well as various sports, primarily netball from the age of six. Like many athletes, I was committed to training hard, impressing my coaches, and striving to reach my athletic potential. However, I also understand the impacts of inadequate fuelling for performance and function. Without sufficient energy intake to support your sports performance, you may feel fatigued during games or competitions, you may even be confused about knowing how much or what to eat, and find it difficult to balance nutrition with performance goals. Conflicting messages from peers, social media, and even well-meaning coaches can add to the confusion. If this sounds familiar, you’re not alone. I’ve created this blog post to discuss a very important topic – RED-S.

What is RED-S?

One of the biggest challenges athletes face regarding their nutrition, is ensuring they meet their energy demands to support both their performance and physiological needs. When an athlete’s energy intake fails to match their energy expenditure, they risk developing Relative Energy Deficiency in Sport (RED-S) - a collection of symptoms that occur when energy availability is too low to support both training and essential physiological functions.

RED-S evolved from what was initially termed the Female Athlete Triad, which was defined by the American College of Sports Medicine (ACSM) in 1992. The triad describes the relationship between low energy availability (with or without disordered eating behaviours), menstrual dysfunction, and decreased bone mineral density in female athletes. Today, RED-S is recognized as affecting all athletes, impacting multiple body systems and heightening the risk of disordered eating behaviours.

How Does Low Energy Availability (LEA) Work?

At the core of RED-S is Low Energy Availability (LEA) - a state in which the body does not receive enough fuel to sustain both daily activities and training demands. Now let me describe LEA in a more practical manner. Imagine your body’s energy availability acting as your phone battery - once that first “20% battery remaining” message appears on the screen, this is the first indicatory signal that you need to recharge to restore your phone’s battery (or in the example of our body, to restore energy balance). By ignoring this signal instead of recharging, you will likely press the “battery saver mode”.

 
Similarly, with LEA, if you do not replenish your body with energy, the body shifts into ‘energy saver mode’. In ‘energy saver mode’ bodily functions such as cardiac, brain, and lung activity continue, as nutrients via blood supply are re-directed to vital organs, however, other physiological processes - including hormone regulation, digestion, and the maintenance of hair, skin and nail health etc are compromised.

Prolonged energy deficiency can lead to metabolic, long-term hormonal, and musculoskeletal impairments, ultimately affecting both health and athletic performance. In young athletes between the fragile ages of 12 - 16, this can be particularly detrimental, as this period is critical for the onset of puberty and developmental growth.

 
Causes of LEA:

1.        Inadequate Energy Intake – Not consuming enough energy to match training demands.

2.        Disordered Eating Behaviours – Restrictive eating, excessive exercise, engaging in fad diets, excluding core food groups and/or avoiding energy-dense foods leading to an imbalance between energy intake vs expenditure.

3.        Lack of Nutrition Knowledge – Not knowing how much food, or what to eat to fuel performance effectively.

4.        Changes in Training – Increased training load, frequency, or intensity without adjusting nutrition accordingly.

Signs & Symptoms of RED-S:

Research demonstrates that RED-S is prevalent among Australian athletes, with approximately 80% of female athletes exhibiting at least one symptom of RED-S. This underscores the urgent need for increasing advocacy to provide evidence-based nutrition education within the sports and athletics communities, particularly among young athletes.

Among those with RED-S, you may experience some or all of the following symptoms:

• Fatigue or low energy levels

• Intentional or unintentional weight loss

• Difficulty gaining muscle mass

• Menstrual irregularities e.g., absence of period (amenorrhoea), infrequent/irregular periods (oligomenorrhoea) in females

• Increased risk of stress fractures due to reduced bone mineral density

• Frequent and/or prolonged illness due to weakened immune function

• Slowed gastric motility causing constipation, bloating and abdominal discomfort.

• Mood changes (e.g., low mood, anxiety, irritability etc)

• Poor concentration and sleep disturbances

Who is at risk of developing RED-S?

Athletes without adequate nutrition knowledge regarding energy demands for sports - particularly those in weight-sensitive sports (e.g., gymnastics, dance, running) are at higher risk, as are adolescents, whose bodies require additional energy for growth and pubertal development.

NOTE: The above examples are foundational nutrition strategies that I utilise to support adequate energy intake and address disordered eating behaviours/patterns in young athletes experiencing RED-S symptoms. If you do experience any of the following symptoms of RED-S or identify with any of the disordered eating behaviours as mentioned above, please seek help from your Doctor/Paediatrician to assess your medical status as well as an Accredited Practicing Dietitian (APD) with knowledge and training in this area to receive tailored nutrition advice for your individual needs and health considerations.

Final Thoughts from Christen-Lee - Accredited Practicing Dietitian (APD)

Your body is your greatest asset in sports or athletic performance - it deserves to be nourished, not deprived. If you're experiencing symptoms of RED-S, know that you’re not alone, and recovery is very possible with the right healthcare professional on your side, and a support system among friends and family. Adequate fuelling will not only protect your current and long-term health and nutrition status, but will also enhance your performance, energy, and overall mental, physical and psychological well-being.

Christen x