How to Fuel an Ironman

An Ironman is one of the most demanding endurance events out there. It isn’t just something you roll up to with no preparation. In fact it takes months of training and planning to get it right, and nutrition is one of the areas that requires planning


The best breakfast before such a big event is one that is high in carbohydrates but also includes a portion of protein to slow down digestion so you don’t feel hungry on the start line. Consuming this around 2-3 hours before the start, should allow the food enough time to settle in the stomach. Above all this needs to be something that you are familiar with and trialled in training; don’t be making drastic changes on race day.

Top Breakfast Ideas:

  • A large bowl of porridge made with milk, topped with a chopped banana or your favourite dried fruits and nuts. Add some extra protein by have a large spoonful of greek yogurt on top.
  • Glass of fresh fruit juice, will help provide more calories and aid hydration.
  • A coffee because Ironman event usually start early and you might need this to wake you up. Don’t worry though, coffee does not dehydrate you like once believed and so feel free to have a cup prior to the event.


Before the race

In the time between breakfast and race start the main aim is to keep hydrated, in fact this is something that needs to be considered in the days leading up to the event. Sipping an OTE hydro tab little and often in the days and hours before the event will ensure you start the event fully hydrated.

Did you know? As little as 2% loss of body weight due to dehydration can negatively affect your sporting performance. So don’t start the race on the back foot by being dehydrated.

Hydration status cannot be reversed in a few hours, in fact it can take a few days to get fully on top of hydration. Keep checking your urine colour and aim for a light straw colour.
You may want to consume an snack an hour before the event, but if so keep it light. Something like an Anytime Bar, jam sandwich or banana would be a good idea.

During the race

This is the section that requires the most planning. During an ironman you want to aim to consume 60-90g of carbohydrates per hour.

Did you know? Our body stores carbohydrates in our muscles and liver, but these stores are limited and get used up during exercise. When we run out of carbohydrates we start to burn fat for energy, which might sounds great, but when exercising at any sort of intensity it isn’t beneficial. Without sufficient carbohydrates stores, the intensity we can perform at decreases dramatically that is why one of the main aims during the event is to keep these stores topped up.

So for a 10 hour Ironman, and an aim of 70g of carbohydrates per hour you would need to consume 700g within the race.
But there are few more considerations you need to take into account:

  • What is being provided along the course in feed stations?
  • How often is it available?
  • Do I get on with the nutrition provided on course?

Remember not all nutrition products are equal in nutritional content. The below is true when using OTE Sports products:

10 hours Ironman x 70g/hour= 700g

*750ml mixed with 80g of energy drink in the bottle.

Depending on how long it takes you to do each leg, here is an idea on how this could be split:

Swim: It is very difficult to fuel during the swim. Try having an energy gel 10 minutes before the start.

Transition 1: Time for another gel and a quick mouthful of water before getting on the bike.

Bike: During this leg aim to consume 4 x 750ml of energy drink, 2 duo bars, 2 energy gels and 2 caffeine gels. Spread the intake out evenly, never going too long before having a sip of drink. Aim to consume half a duo bar or gel every 30 minutes, saving the caffeine gels for the later part of the bike.

Transition 2: Time for another big gulp of water and another energy gel, before moving on to the run.

Run: During this there are 2 more energy gels, 3 caffeine gels and the final bottle of energy drink to consume. I would also advise having some water as well from feed stations, especially if it’s a hot day. Again the idea is to split these up evenly during the run.

This may seem like a lot of sports nutrition but OTE Sports designs their products to be pH neutral and so kind on the stomach over such a long period of time.
Total calories consumed during an Ironman can be in the region of 6000-8000kcal. From consuming the above you will have taken on board just over 3000 kcal, your fat stores will also contribute around 1750kcal to this total, but inevitably you will be left in a calorie deficit. This leads us on to recovery.


Post Race Recovery

As soon as the event finishes it is important to consider nutrition for recovery. An OTE Recovery drink containing both protein for rebuilding muscles, carbohydrates to replenish your stores and fluid to aid rehydration are perfect for this. Aim to consume within 30 minutes of finishing as this is seen as the ‘window of opportunity’ to kick start the recovery process. Chances are you will probably not willingly want to consume this, but it is a case of needs must.

Nutrition going forward

Unfortunately recovery shakes aren’t miracle workers, and it is only the first (albeit very important) step to recovery. After the event look to consume small meals/ snacks every 3-4 hours. Make sure these both consume a portion of carbohydrates and a 20-25g serving of protein. The idea being that you are slowly providing your body in manageable amounts of food to be used in the recovery process.

Snack ideas could be:

  • A bagel with cream cheese and ham
  • A tuna pasta pot
  • Bowl of granola with greek yogurt
  • High protein smoothie
  • Chicken and Cous cous salad

All that’s left to say is Good Luck if you are taking on an Ironman and don’t underestimate the importance of nutrition on the big day.