Fuelling for Triathlon - Dr Lauren Duckworth

Triathlon nutrition

Fuelling for Triathlon

The Triathlonbox team have been really privileged to work with Leeds Beckett University over the past six months a had the pleasure of giving Lauren some triathlon race day tips and she has written this fantastic article to help triathletes to get the most out of their race day experience.  Over to you Lauren.

Author  Dr Lauren Duckworth, Senior Lecturer in Sport and Exercise Nutrition, Leeds Beckett University

Academic Associate of the Sport and Exercise Nutrition Register

If you're planning to take on a triathlon this year, getting your training and competition nutrition right can make all the difference to your progress and performance. Here we outline how to find a fuelling strategy that works for you and get better race-day results…

Triathlon nutrition:

With three events combined, plus six distances to choose from, it’s important to have an understanding of demands placed on your body during a Triathlon, to know which fuels to choose. In shorter sprint distance Triathlon’s you can get away with not having to provide your body with too much extra fuel, other than eating well in the days before a race to make sure your stores are topped up.  For races where you’ll be competing for over two hours, Olympic, half Ironman and Ironman distances in triathlon, you’ll need to consider fuelling before and during the race for the best performance possible.  The beauty of triathlon is the three disciplines, and you can adapt your fuelling in each leg of the race.

Race day Fuelling

Energy in our body is stored in our muscles as glycogen, which is provided mainly by carbohydrates in the diet.  Glycogen is converted to glucose and provides our muscles with energy when we need it, along with any immediate form of carbohydrate we may provide our bodies during the race.  Depending on your gender, body size, and the temperature, terrain and intensity of the race you will use up roughly 500-1,000 calories per hour.  Your body stores contain roughly 500g of carbohydrate (2,000 calories), enough to last you for around 90-120 minutes.  It’s when we run out of these stores, or don’t top them up during a race, that fatigue kicks in.  It takes some time for carbohydrate to be absorbed, so you need to think about fuelling from the start of a race to make sure you avoid running out.

Carbohydrate Loading

The concept of carbohydrate loading is popular amongst triathletes prior to race day. Carbohydrate loading is more than simply eating pasta for dinner the night before competition and should be tapered around training.  As training decreases leading into a race, try to maintain your energy and carbohydrate intake. This way, the 600 to 1,000 calories you generally expend during training can be used to fuel your muscles. To adequately fill muscle glycogen stores, athletes need to consume between 7-12g of carbohydrate per kilogram body weight a day for 24-48 hours prior to competition. The total amount of carbohydrate consumed by an athlete in the days leading into a race will depend largely on the length of the triathlon.  For sprint and Olympic distance competitors the taper in training leading into the race in combination with 7-8 g of carbohydrate per kilogram body weight for 24 hours before the race is adequate to increase muscle glycogen stores. However, athletes competing in half ironman and ironman races should increase their carbohydrate intake to around 10-12 g of carbohydrate per kilogram body weight for 48-72 hours before race start.

Pre race preparation

Everyone has different levels of comfort regarding eating before exercise, especially swimming, so it is important to trial what works for you. In general, try to consume around 150g of carbohydrate and allow 2-4 hours to digest a larger meal before your swim, and 30 minutes-2 hours for a smaller carbohydrate snack nearer to the race.  Consider the Glycaemic Index (GI) of carbohydrate.  Lower GI foods, give a slower release of energy and should be the focus of main meals before an event (e.g. porridge, muesli, wholegrain toast, eggs, yoghurt without sugar). High GI foods are quickly broken down to glucose and therefore are more readily available for energy, making great options for snacks before, during and after a race.

During a race

As a general rule, aim for 60g of carbohydrate per hour.  This can be in the form of a gel, bar, chews or drink.  If you do wish to consume solid foods, make sure the fat and protein content of these are low (no more than a few grams) to avoid gastrointestinal upset.  It’s hard to prescribe a one-size-fits-all as everyone has a personal preference on how best to consume their fuel.  What you must do is practise your chosen method during training before race day, and try different combinations to see what works for you.  It’s often easier to eat on the bike so it’s a good time to refuel with solid foods if possible, and save the more transportable foods for the run.  It’s wise to find out what energy gel brands and foods will be available at feeding stations along the route too, so you can factor this into your fuelling strategy. As a guide, the following would provide you with 60g every hour:

2 gels (~25g carbohydrate each) and a small amount of drink
1 gel and a bottle of sports drink (~30g carbohydrate)
1 energy bar (~40g carbohydrate) and half a bottle of sports drink

When checking how best to make up these 60g, look at the carbohydrate content, per serving, on the food label of these products.

For ultra-endurance events (half ironman and Ironman distances) you may need up to 90g of carbohydrate per hour, whereby it is advised to consume products providing multiple transportable carbohydrates (ones with glucose/fructose mixtures), as this will be the only way to achieve high rates of carbohydrate delivery.

After a race/training event

If you're training hard for a race, getting your triathlon recovery right is vital for minimising muscle soreness and improving your performance for the next session.  Both carbohydrate and protein are critical for full recovery after training. The body can only store a certain amount of carbohydrate, once depleted through exercise these reserves need to be replaced before your next training session. Protein is vital for the growth and repair of muscle tissue and as hard training depletes the body's stores it is important to refuel with high-protein snacks as soon as possible.  As a guide, the recommendations are to consume around 20g of protein ideally within 30 minutes after exercise, and a minimum of 1g of carbohydrate per kg of body mass (i.e. 75g if you weigh 75kg) every hour for up to 4 hours after exercise.

Triathlon Hydration

If you are a slower athlete, drinking to thirst should work fine as a hydration strategy. If you are going a bit faster, it’s good to have a plan.  Depending on your body size, and the environment you are racing in which will dictate sweat rates, the fluid plan that suits most athletes is to consume of 400ml-800ml per hour, although this needs to be customised to the athlete’s tolerance and experience, their opportunities for drinking fluids and the benefits of consuming other nutrients (eg, carbohydrate) in drink form.  Try to drink in the early parts of a race when the gastrointestinal tract can absorb both fluid and carbohydrate.  Don’t drink excessively and use common sense. The goal should be to lose a little weight (2 to 4 pounds) at the finish line. You definitely want to avoid weight gain, which clearly would be a sign of drinking too much. In hot environments dehydration can definitely be a very important factor. Don’t forget that good hydration starts before the race, and hydrate well in the days leading up to your race.


#teamtribox thanks our author - Dr Lauren Duckworth, Senior Lecturer in Sport and Exercise Nutrition, Leeds Beckett University for taking the time to give advise on triathlon recovery and fuelling.  We hope that this helps you be your best come race day.


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