Female Athlete Series: Part 3: Relative Energy Deficiency in Sport with Dane Baker

As an endurance athlete, you need ample energy from food to support your gruelling training schedule and crush your triathlon goals. But restrictive diets and inadequate fuelling habits can backfire, plunging you into a state of low energy availability that derails your performance.

Below, leading sports dietitian Dane Baker unpacks the warning signs, consequences, and solutions for low energy availability, also known as Relative Energy Deficiency in Sport (RED-S).

Arm yourself with the nutrition know-how to optimise your workouts, accelerate your recovery and feel your absolute best in training and racing.

What is Low Energy Availability?

Low energy availability occurs when your energy intake from food consistently falls below the demands of your exercise regimen. Your body is left with insufficient leftover fuel for optimal functioning after accounting for your training expenditure.

Prolonged low energy availability causes your body to downregulate and compromise multiple systems, including:

• Menstrual function
• Bone health
• Metabolic rate
• Immunity
• Cardiovascular health
• Gut function
• Hormones

This cascade of negative effects is known as RED-S. Females with irregular or absent periods are at high risk, but males can also suffer the consequences.

How to Spot the Warning Signs

Be on the lookout for these clues that your energy availability may be too low:

• Irregular or absent periods
• Persistent injuries and illnesses
• Poor sleep quality
• Inability to gain strength or fitness despite training
• Fatigue and low energy levels

Males may also experience reduced libido, sexual performance issues, and mood disturbances.

If you suspect low energy availability, consult an accredited sports dietitian and sports physician for proper diagnosis and treatment. Blood tests, bone scans and clinical assessments are needed to rule out other potential causes. Don’t try to self-diagnose.

The Gradual Continuum of Risk

Energy availability exists on a continuum - it’s not black or white. You may dip into low availability occasionally after an intense training block or race without major effects.

But consistent, prolonged low availability primes your body for dysfunction. Research suggests reproductive hormones start decreasing within 24-48 hours below an availability of 30 kcal per kg fat-free mass. Meanwhile, bone health declines below 45 kcal per kg FFM.

Aim to keep your availability consistently above 30 kcal/kg FFM as an absolute minimum, with 45 kcal/kg FFM or more ideal for supporting training demands and long-term health.

Practical Tips to Maintain Availability

Here are some practical strategies to help you maintain adequate energy availability:

• Eat breakfast pre-training to start sessions fuelled
• Consume carbs during longer or higher intensity sessions
• Refuel quickly after finishing training
• Vary your energy and carb intake day-to-day based on your training loads
• Don’t fear carbs - they provide key fuel for intensity
• Include protein in meals and snacks for repair and recovery
• Periodise nutrition just like you periodise training
• Work with a sports dietitian to develop an individualised fuelling plan

The key is consuming sufficient energy to match your training demands. Let go of restrictive habits and be proactive with your fuelling to keep availability in a safe zone. 

You’ll bounce back faster, maximise adaptations, and avoid the disastrous domino effect of RED-S.

To dive deeper, listen to the Triathlon Nutrition Academy Podcast, EP 121 - Female Athlete Series: Part 3: Relative Energy Deficiency in Sport with Dane Baker  

If you are interested in learning more about the Triathlon Nutrition Academy Program and what it can do for you, head HERE to learn more.