Triathlon Nutrition For Competition - Get It Right on Race Day!

Race Preparation, May 07, 2021

Getting your triathlon nutrition for competition right - so what you eat and when - can have a big impact on the outcome of an event.

Dehydration and running out of energy are common causes of fatigue in a race. 

Getting your energy intake right is even more important the longer the duration of the triathlon. 

Nutrition is something you should spend a bit of time thinking about and practicing before race day to make sure you get it right. 

You don’t want all that training to go to waste because you’ve run out of energy, or eaten something that doesn’t sit well in your stomach!

Getting your triathlon nutrition right can make the difference between a great race and a really nasty one! 

Pre-Race Triathlon Nutrition: Days Leading Up To A Race

High pre-race muscle and liver glycogen (the stored form of carbohydrate) concentrations are essential for optimal performance. 

If you are preparing for a long distance triathlon (ie longer than Olympic distance) you are likely to benefit from ‘carbohydrate loading’. 

Even if you are only doing an Olympic distance race it is possible that you could still benefit from getting your carbohydrates stores as high as possible.

Traditionally athletes would deplete their carbohydrate stores before eating a high carbohydrate diet and reducing their training load in the lead up to a race.

However now studies have shown that you can achieve high muscle glycogen levels by just following a high carbohydrate diet for one day. Also these high levels can be maintained for at least 3 days if you don’t do any exercise and a have a moderate carbohydrate intake.

What this means for your triathlon nutrition in practice:

At least one day before the event:

take on 10g of carbohydrate per kilogram of bodyweight.

If you are unable to do this the day before the race: have a day of high (as above) carbohydrate intake 3 or less days before the race. So long as you rest between then and the race you will maintain high muscle glycogen levels.

Triathlon Nutrition: The Hours Before A Race

Triathlon races often start early in the day, and therefore it is easy to miss breakfast due to lack of time or not feeling hungry. It is vital however that you do take on board some fuel. See our triathlon nutrition for training and recovery page for some tips on what to eat.

At least 2 hours (preferably 3 – 4 hours to allow better digestion) before a race you should aim to take on board a meal rich in carbohydrates and low in fat and fibre. This will provide you with the energy required whilst being easily digestible. The quantity of carbohydrate should be about 2g per kilogramme body weight.

Some triathletes struggle with eating within an hour before exercise due to something called ‘rebound hypoglycaemia’. This is when there is a rapid fall in blood glucose levels 15 – 30 minutes after consuming glucose (in the form of carbohydrate). Only 2 research studies have found this to negatively affect performance – most showed no change or an improved performance following glucose ingestion in the hour before exercise.

If you do find eating shortly before a race/training to cause problems, then try eating low-glycaemic index foods (such as oats).

It is important that you practice the timings and what you eat before race day. Everyone is different with regards how well they digest different foods and what sits well in their stomach. The last thing you want is to be feeling sick or bloated just before a race!

If you can’t face eating anything, then try drinking something, for example a smoothie, sports drink or liquid meal supplement.

Triathlon Nutrition for Sprint/Supersprint Distance Races

These races can be short enough not to need to eat (depending on how long you take to complete the race). However you should take a sports drinkon your bike so that you can top up energy levels and minimize dehydration, particularly if the weather is hot. 

Also, several recent research studies have shown that even with exercise lasting an hour carbohydrate intake may have a positive effect.

In an event lasting 60 – 90 minutes, if you find that taking on board any fuel causes gastrointestinal problems, you’ll be interested in this recent research:  rinsing the mouth with a carbohydrate drink was enough to improve performance during 1 hour of cycling. So have your bottle on the bike, and just swill and spit!

Triathlon Nutrition for Olympic Distance and Ironman

If you are going to be racing for longer than an hour then maintaining your energy stores is vital. An Ironman can take anything from 8 to 17+ hours to complete, and so the nutritional requirements are different compared to shorter triathlons, and will also vary depending on how long you’re going to be racing for.

Racing over several hours (eg for an Ironman) means you will be missing regular meals. Combine this with the fact you are expending more energy than normal and you’ll see why taking on board enough fuel becomes hugely important. You will not finish the race if you don’t keep your energy supplies topped up!

A recent study showed that during an Ironman, the amount of carbohydrates taken on correlated with finish time in men. The same was not seen for the women.

During a race you need to consume roughly 1g of carbohydrate per kg body weight per hour of exercise.

The best time to get this on board is during the bike leg. Some people say you should look at this part of the race as a ‘rolling buffet’! It is much easier to eat during this leg than the other two, and allows time for some digestion to occur before setting off on the run where tummy discomfort is more likely. 

If you can get your carbohydrate intake up to 1.5g per kg body weight per hour during the bike leg this could be beneficial. There is no point in taking more than this, as your body will not be able to keep up with digesting a higher rate.

Generally the energy you take on board during a race will be in the form of a gel or drink. It is worth taking a close look at the ingredients of your chosen product, as the type of carbohydrates you take on board can have an impact. 

Not all carbohydrates are oxidized at the same rate and therefore they may not be equally effective.

Glucose, sucrose, maltose, maltodextrins and amylopectin are oxidized at high rates, which is what you want. Fructose, galactose and amylase are oxidized at rates 25 – 50% slower. 

Combinations of different carbohydrates may be best to enhance total carbohydrate absorption. 

Recent studies from the University of Birmingham (England) have shown that combining glucose and sucrose, or glucose and fructose led to higher oxidation rates than glucose alone, but whether this leads to improved performance is still unclear.

Hydration is also very important.  Have a look at our hydration page for more information.

What Do I Do If I Get Stomach Discomfort During Racing?

During hard runs and racing many triathletes experience gastrointestinal problems. Symptoms include stomach cramps, diarrhoea or wind, burping, heart burn. 

The cause is unclear but it is thought to be related to the intensity of the running, stress of competition, and perhaps dehydration or over hydration. 

In addition these sort of problems are more likely to occur if you have ingested foods containing fibre, fat, protein and/or drinks that have high concentrations of carbohydrate. 

Sometimes you will be able to pinpoint specific foods that cause the problems, but it is also good to experiment with the type and timing of foods before training and competition. Often people prefer to race on an empty stomach, having eaten their last meal quite a few hours in advance. An alternative would be to take on board a liquid meal supplement. These are easily digestible but don't fill you up too much. They are also good for after training if you don't feel hungry enough to eat proper food. 

Liquid meal suggestion: 

  • 300ml skimmed milk with 4 teaspoons milkshake powder 
  • 300ml skimmed milk with 150g very low fat fruit yoghurt 
  • 300ml skimmed milk with 100g low fat fromage frais 
  • 300ml skimmed milk with tablespoon skimmed milk powder 

Ironman training can be high in volume, and some people may struggle to maintain a healthy bodyweight. If this is the case, then a good plan for your triathlon nutrition would be to try including some of these meal replacement drinks on top of your usual meals. 

Triathlon Nutrition For Racing Take-Home Tips:

  • Plan your energy intake well before racing
  • How long will the race last?
  • How much carbohydrate will you need? 
  • What are you going to consume to get this energy? 
  • Will there be feed/drink stations during the race? 
  • And if so where will they be and what will be provided? 
  • Is it going to be hot? 
  • Practice this in training a few times to make sure it works.
  • Think about your nutrition during the race – don’t forget to put your nutrition plan into action!