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Fuel your training day – energy availability

Quite often athletes realize during their season that they are not able to recover, to do all their exercises the way they would like them to do. They lack the energy. And although they feel they are not getting enough energy, they are not losing any weight either. Symptoms such as chronic fatigue, frequent infections and illnesses, decreased strength, gastrointestinal problems or disordered eating thoughts are common in these situations.

Especially youth athletes have to manage school and training, others who have not made it to the pro level yet need to mange their job and training. Sessions happen early in the morning or late in the day around work and/or school.


Watch your energy intake


In order to be able to reach your best and stay at your best, you need to manage your energy intakes during the day. Staying on top of your fueling is a top priority if you want to perform at your best. Energy is needed – not only for your training but also for your health, your daily activities and your growth.

One way to make sure you are not ending up in such a situation is to monitor your energy availability. Energy availability refers  to the energy that is left for your body’s functions when you subtract all the energy you need for your training from the energy that ones from the food you eat. If there’s nothing left, then you run the risk to experience some of the symptoms mentioned above.


Find your strategy


Sometimes it’s hard to manage our energy availability. With a busy schedule it might get hard to find the time to eat. Sometimes we are rushing from one appointment to the next one and simply forget to eat. This can result in a negative energy balance. Also an increased training load without an increased energy intake can cause an energy deficit. This resulting low energy availability leads to physiological changes (metallic, hormonal, functional) which ultimately affect your performance.

Although low energy availability can cause weight loss, it does not always trigger weight loss. The body will also try to adjust its energy needs to be able to survive with less energy. A constant energy deficit can for example cause the menstrual cycle. First the cycle starts to jump, then it stops completely due to a change in the hormonal status. Bones get affected by low energy availability as well. Stress fractures or poor bone mineral density can be caused by insufficient energy intake.


To make sure you don’t run the risk of a big energy deficit, nutrition plays a key role in how you manage your training load:

  • The more you train, the more energy you need.
  • The higher the training load, the more important is your increased carbohydrate intake.
  • Include snacks around your training sessions and fuel during training when work loads are high.
  • Never skip a meal.
  • If you’re not hungry, try a smoothie, milk shake or meal replacement.
  • Follow a good nutrition plan to best support your training and competition schedule.


Mounty et al (2014). The IOC consensus statement: beyond the Female Athlete Triad – Relative energy deficiency in Sport (RED-S). Br J Sports Med 48, 491-497.

Viner et al (2015). Energy Availability and dietary patterns of adult male and female competitive cyclists with lower than expected bone mineral density. IJSNEM 25, 6, 594-602.