Triathlon nutrition: how to get fuelling right

Renee McGregor explains how to get your triathlon fuelling right, whatever your ability


The main difference between healthy eating and sports nutrition is the attention to detail and the fine-tuning of nutrient delivery. In healthy eating, the ultimate goal is to promote long-term good health and fend off increased risks of disease, while maintaining a balance so that food is still enjoyable. In comparison, sports nutrition, although still based on healthy eating guidelines to an extent, is performance driven, whether that’s running for 45mins three times a week or training to compete in an Ironman event.


Making the right nutrition choices to suit not only your specific sport but the intensity of that activity within your given training session will ensure that you have: Put the right amount and type of fuel into your body to meet the demands of your session, allowing you to perform at your best ability; Made the correct choices after your training session, which will allow your body to adapt to your training and make it stronger within your chosen

Don’t forget the adaptations

The key to good sports nutrition is preparation and organisation; fundamentally, to achieve your goal you need to tailor your nutrition to the exact training session. It’s not just about energy in and energy out. I’ve lost count of the number of athletes who think they can get away with eating poor nutrient-dense foods just because of the amount of training they do.

They may well maintain their weight and have the energy to train, but what they don’t see are the adaptations, such as: increases in strength and lean muscle mass; improvements in performance within their chosen sport; good consistency between training sessions so that each one can be done to the best of their ability; and good sleep patterns, good mood and high energy levels.

By just meeting energy demands, you may be able to carry out your training but you may not see any actual improvements in your overall performance.

Nutritional adjustments

Although so far what I’ve mentioned regarding sports nutrition is applicable to anyone with a performance goal, it becomes even more important when working with elite athletes. Helping them to periodise their nutrition around key competitions is vital for success. Just as training needs to be adjusted to ensure that the athlete can train consistently well over several months without becoming injured or ill, nutrition has to meet these demands accordingly.

Even during relatively low-intensity weeks, advice will be provided to maximise immune function, recovery and rest. 

So for example, for an athlete who’s competed in a major event and is in an active recovery phase, although training volume and intensity may be significantly reduced the body will be at more risk of injury and illness. For examples of good nutrition strategies to include, see the middle panel, left.

Fuelling the female triathlete

Additionally, for female athletes it’s essential that during this recovery phase nutritional intakes and body composition allow for regular menstruation. When working with elite female athletes, the ideal is to maintain regular menstruation function throughout the year. However it’s inevitable in some cases and sports that increased training volumes can lead to some irregularity.

The aim will always be to prevent absence of three consecutive periods; if this is exceeded the consistently low oestrogen levels can affect bone density, putting the athlete at an increased risk of stress fractures.

Similarly before a major competition, nutrition will be adjusted according to training load, ensuring:

  • Sufficient intake of carbs before and after training.
  • The use of a probiotic 12 weeks prior to competition to support immune function during a high training volume.
  • Athletes aren’t dehydrated as this reduces saliva production – again important for first-line defence of the immune system.
  • Monitoring body composition to ensure goals and targets set at the start of the season are being met in an appropriate manner.
  • Regular blood tests to monitor inflammation, muscle damage, fatigue, immune function and iron stores.

So whether working with an elite or recreational athlete, my aim is always to help ensure nutrition is tailored to training loads, intensities and volumes for maximal performance gains; when working with the elite, there are additional considerations and discussions within a wider team necessary for the same outcome.


Want more expert advice on how best to fuel your training and racing needs? Then take a look at our huge nutrition section.