Under-fuelling and training: understand low energy availability and REDs

What low energy availability means

The 2023 IOC consensus describes REDs as a syndrome linked to problematic, prolonged or severe low energy availability. It can affect multiple body systems and occurs in athletes of different sexes. Energy availability concerns the energy remaining for bodily functions after exercise demands; it is not simply a label for being a certain body size.[1]

The consensus also stresses that individual signs can have causes other than under-fuelling. Losing a period, feeling exhausted, or sustaining an injury does not establish REDs on its own. Those observations are reasons to seek an assessment.[1]

Notice patterns that deserve a conversation

• Persistent fatigue or a continuing fall in training performance.
• New menstrual changes, including missing periods.
• Recurrent injuries, particularly suspected bone stress injuries.
• Difficulty recovering, increasing food anxiety, or a training schedule that leaves little room to eat.

You do not need to wait until every item applies. Discuss persistent changes with a clinician, and mention your training demands, eating pattern, menstrual history, injuries, medications, and other relevant symptoms. Tests and assessment can help consider alternative explanations.

Make fuelling part of the program

The ISSN position stand for female athletes prioritizes adequate energy intake and attention to the timing of food around training. It is a sports-nutrition framework, not an individualized calorie prescription. Needs change with the person, the sport, and the circumstances.[2]

Practical questions can be more helpful than guessing a daily energy target: Is there time to eat before the session? Can you have a meal or snack afterward? Are long work or travel days making meals difficult? A registered dietitian with sports experience can help turn those answers into a workable plan.

Choose recovery with support

A clinician-led plan may involve changes to training, food intake, and treatment of related health issues. Avoid using a self-calculated energy-availability number or a wearable’s calorie estimate as proof that you are adequately fuelled. The IOC assessment tool is intended for clinical use.[1]

If eating or exercise feels difficult to control, include mental health support in the conversation. You can ask for care before your symptoms become severe. The goal is a healthier relationship with the activities you value, not a faster return to the same unsustainable workload.