How the body responds to not eating enough to support training

Posted on September 1, 2020 by

We previously considered some of the signs and signals your body is giving you to create an awareness of if you’re eating enough food to match your training load on any given day.

Read “6 ways the body tells athletes if they’re eating enough”.

If you keep eating what you always eat while life and training changes around you then it can be hard to see that what you’re eating now isn’t enough. That’s why these internal messages act as reminders to make you reassess what and when you’re eating to stay on top of demands.

If you ignore these early warning signs and you regularly aren’t eating enough to support training, there are some more serious and long-term implications which will impact your health and training potential.

Below are six of the longer-term health risks that show up as a result of regularly not eating enough.


1. Recurrent Injuries

If you feel like you are constantly at the physio with a recurring injury that is just not resolving. Alternatively, you may be experiencing multiple injuries in a row/over one season. This is due to the body not having sufficient energy to recover after training or the fuel available to rebuild and repair.


2. Stress/Bone Fractures:

Systems that support hormones and bone health also need ongoing and consistent energy. It may be that a stress fracture is a sign you are not eating enough. Bone porosity can also be evaluated by a scan (DEXA) to confirm the likelihood of an increase risk for bone fracture.


3. Repeated Illness

If you’re frequently (or more regularly) coming down with a cold then this could be linked to the body being under extra stress and the immune system being compromised as a result without enough energy to effectively fight off infection.


4. Difficulty maintaining or manipulating physique

If your intension and training is to gain muscle mass but you aren’t, it could be that your body has insufficient energy to support laying down lean mass. Conversely, if you are trying to reduce your skinfolds and you aren’t seeing the intended result, your body could just be conserving weight to manage inconsistent energy intake.


5. Light, irregular or ceased menstruation

If your cycle suddenly stops, becomes erratic or from month to month lighter and lighter this could be a reason for concern as there is not enough energy for basic physiological functioning of the body, let alone enough to spare for training demands.


6. Poor or inconsistent testing results

If you find that your strength and conditioning testing results or sports specific testing results are worse than previous results or not where you would expect them to be despite consistent training, it could be that there isn’t the energy to fuel the activity you are doing to create training adaptations.


The collective term for these symptoms is RED-S (Relative Energy Deficiency in Sport) or low energy availability, as a result of not having adequate energy available when the body needs it. Either term may be used to explain the need for greater alignment what you are eating with when and how much you are training.

Working with your Sports Dietitian can be an effective way to assess if you are in fact in low energy availability and how to modify the quantity of food, macronutrient intake or additionally the timing of meals to rectify it.

Not eating enough is not always something which is done intentionally to create an energy deficit, next time we will look into RED-S in more detail to understand how it comes about, why it creates these issues and some strategies you might take to manage or avoid it.

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