Ironman Nutrition, Diet & Food: The Complete Guide

Ironman Nutrition, Diet & Food: The Complete Guide

Understanding how to fuel for an Ironman triathlon with nutrition can be a complicated business. The 2.4-mile swim, 112-mile bike and marathon finisher is a huge endurance effort that requires a carefully mapped out fuelling plan.

You’re going to be in the water, in the saddle and on your feet for at least a full working day – the official Ironman world record is 7:35:39, so even the elites don’t get much change from eight hours.

Fuelling correctly is essential if you’re going to last the distance. And taking on the right Ironman nutrition at the right time, can mean the difference between crossing the finish line tired but smiling, and a day-long sufferfest.

Sadly, there’s no off-the-peg solution to fuelling an Ironman triathlon. Everyone’s different. Everyone runs, cycles and swims at different paces, and everyone reacts in different ways to different foods.

Luckily, there are some basic Ironman nutrition principles to keep you healthy through the months of training, supply the energy you need on race day and support your recovery.

The energy you need to complete an Ironman comes from a ratio of 65% carbohydrate and 35% fat. Our bodies already have enough fat to fuel an Ironman, but our carbohydrate stores run out after 90-120 minutes. Your Ironman nutrition should include carbohydrates for fuel and protein for recovery.

Whether this is your first Ironman or you’re gunning for a podium spot at Kona, Veloforte has used all of its expertise to put together the Ironman nutrition plan below.

Use it as a guide and experiment with different foods, drinks and sports supplements in training and then, when it comes to race day, you’ll have the perfect Ironman fuelling strategy to carry you over the finish line.

Find your perfect ironman nutrition

Simply complete our 2-minute quiz to find the perfect natural ironman nutrition for you. Plus, receive a 15% off coupon code to spend right away. 

Important nutrients, vitamins and minerals for an Ironman

When thinking about an Ironman triathlon, it’s a good idea to brush up on the key nutrient building blocks that help you swim, bike and run and support recovery to keep you healthy through the gruelling months of training.


The body uses carbohydrates as its preferred fuel for exercise, converting them into energy, which can be used immediately or stored in the muscles and liver as glycogen.

Our bodies can only store enough glycogen for around 60 to 90 minutes of exercise though, so you’ll need to top up with carbs during longer training sessions and on race day to avoid bonking. 

Finding something you can eat on the bike or run (we don’t recommend snacking during the swim!) to give you that vital energy without causing stomach cramps is key for Ironman success.


Protein is an essential part of any healthy diet. For triathletes it’s particularly important as it supports recovery after exercise and aids the repair of those microtears in your muscles caused by tough sessions.

How much protein you need varies depending on factors such as sex, weight and how active you are. As a rule of thumb though, the British Dietetic Association recommends endurance athletes consume 1.2-1.8g of protein per kg of body weight each day.Ideally protein should be eaten every three to four hours throughout the day, so try and include a protein source with each meal. 

After a hard training session you can also try a snack such as a Veloforte Mocha or Forza protein bar, which have the perfect 3:1 ratio carbs to protein or try one of Veloforte’s new protein shakes for optimal recovery.


While you should try and reduce the amount of trans fats and saturated fats you eat – the ones found in biscuits, crisps and fatty red meats – good fats are an essential part of any Ironman nutrition strategy. 

Monounsaturated and polyunsaturated fats found in oils, avocados, nuts, seeds and fish, help your body function properly and allow it to absorb the fat-soluble vitamins A, D and E.

Eating good fats could also help reduce inflammation in the body, lower blood pressure and reduce the risk of heart disease. Fat can even be used as fuel during low-intensity exercise.


Sodium is the main electrolyte we lose through sweat – hence those salty, white trails on your skin after a tough workout.

Electrolytes are salts and minerals found in the blood that conduct electricity when mixed with water. They’re essential for normal bodily function, help keep you hydrated, regulate nerve and muscle function, regulate your blood pressure and PH level and help rebuild damaged tissue.

Most of the sodium we consume is sodium chloride, aka table salt, and guidelines recommend healthy adults need 1,500 to 2,300 milligrams of sodium per day. However, endurance athletes, such as Ironman triathletes might need more, depending on a number of factors including the duration and intensity of your training, your age, sex, weight, the temperature and your sweat rate and sweat sodium concentration. 

Carefully balanced electrolyte powders offer a convenient and delicious way to top up, they’re ideal when you’re on the bike or run or to place at the side of the pool to sip during a tough training session. Low-carb Solo is also ideal added to your regular water bottle for drinking throughout the day.

Potassium and Magnesium

Potassium and magnesium are two members of the essential electrolyte family. Importantly for athletes, potassium helps with muscle contractions – including the heart and digestive system – and aids energy production.

Magnesium also helps you maintain a regular heartbeat and regulates the use of nutrients for energy. It can help promote sleep, too, an essential component of recovery if you’ve been training hard.

Best Ironman food

At Veloforte we’re big believers in ‘real’ food. Most of the vitamins and nutrients you need for optimal performance can be achieved through your daily intake, so a good Ironman training diet should be well-balanced and include fruit, veg, slow-release carbs and lean protein at least 80% of the time.

Adding some of these foods to your diet could also help you train at your best.


Bananas are the perfect portable food. You can eat them as a snack throughout the day and pop one in your jersey for an energy boost in the saddle.

Bananas contain fast-acting easily-absorbed carbs to give you energy as you train, as well as potassium to support muscle function.

Bananas could help reduce muscle cramps and soreness in athletes, and studies have found they’re as beneficial as sports drinks for providing energy when cycling.


There’s a reason so many coaches recommend starting your day with porridge. Oats are low-to-moderate GI, which means they provide slow-release energy. That makes them great before training. 

They also contain more protein and iron than most grains and can help regulate your blood sugar, so you don’t get energy spikes and troughs.

Jonny Brownlee regularly starts his training day with a bowl of porridge or Bircher muesli. But there’s no need to save oats for breakfast, try them in a snack bar or healthy flapjack (not one loaded with processed sugar) for energy throughout the day.


Even if you’re not a fan of the pink stuff, it’s worth persevering for the performance-boosting benefits. Beetroot is rich in nitrates, which can help the body use oxygen more efficiently. 

Researchers found that athletes who consume beet juice, containing 300-500mg of nitrate, two to three hours before exercise, see a one to three percent improvement in performance.

While most sports studies focus on beet juice, eating the vegetable whole is thought to have similar benefits.


Eggs are a great source of protein for recovery. Two medium eggs provide around 15g of protein and 100% of your RDA of vitamin B12, which helps you unlock energy from food. Hard-boiled eggs also make a great protein-rich post-training snack.

Sweet potatoes

Another great source of slow-release carbs, sweet potatoes contain vitamins A and C, which are beneficial for the immune system. There’s some evidence that vitamin C could help active people ward off colds, which you may be more susceptible to when you’re training hard, too. They’re lower GI than white potatoes so will give you a more steady supply of energy.

They also provide iron, which helps keep your energy levels high, and potassium and magnesium that helps with muscle and nerve function.

Energy bars

Energy bars are the perfect portable snack for a pre-training energy boost, glycogen top ups on the bike and post-sufferest recovery.

Veloforte’s energy bars are all natural and contain the perfect balance of essential proteins and dual-source carbohydrates for sustained energy. Experiment with the whole range to find your favourite and pick n mix to prevent flavour fatigue on longer rides.

Energy gels

When you’re on the move, the blood needed to aid the digestion process is sent to your working muscles, making it harder to digest food. But you still need to top up your glycogen stores on longer training runs and race day.

Energy gels are a handy source of fast-release carbohydrate, but not all energy gels are created equal. Many people find traditional, highly-processed gels are over sweet and can cause stomach cramps and tummy trouble.

Veloforte’s all-natural energy gels are specially designed to be gentle on the stomach. Using ingredients found in nature, such as date, beetroot, lemon and ginger, they’re much tastier, too.

The dual-carbohydrate format gives you energy – fast – and they also contain electrolytes to replenish those lost through sweat.

Importance of ironman hydration

When it comes to planning your nutrition for Ironman training and race day, don’t forget the hydration. Fluid intake is often overlooked but, according to British Cycling, just 4% dehydration will decrease your capacity for muscular work and affect your performance. Not what you want on race day.

Even mild dehydration can cause fatigue, feelings of dizziness, muscle cramps and increase your rate of perceived exertion (RPE), making training feel much tougher.

The NHS recommends drinking around 1.2 litres of fluid a day to replace normal water loss but if you’re exercising and sweating heavily, you’ll want to increase that. Your individual needs vary depending on a number of factors such as age, weight, exercise intensity and the weather, but as a rough guide, aim for one-and-a-half litres of fluid for every kilogram of body weight you lose during a tough exercise session.

And remember, as you sweat you lose essential electrolytes too, so add some Veloforte electrolyte powder to your water bottle. The fruity blends offer real fruit, botanicals, pure electrolytes, energy and natural caffeine to keep your electrolyte balance on an even keel.

Ironman nutrition plan

The correct fuelling strategy for an Ironman really does vary from person to person. It’s a fine line between taking on enough calories to avoid bonking or hitting the wall, and feeling sluggish, bloated or suffering stomach cramps.

As a rough guide, you should be taking on around 60-90 grams of carbohydrates each hour during an Ironman event. Ironman triathletes typically consume most calories during the bike leg when it’s easier to digest real food as well as sports products. 

During the run, you’ll probably find it easier to rely on gels and sports drinks. And don’t forget, you’ll need to replace water and electrolytes lost through sweat to keep your body functioning normally, too.

Use these pre-race, race day and post-race guidelines as a base to build your own personal Ironman or half ironman nutrition strategy.

Three days before your Ironman

Two to three days from your race, start increasing your carbohydrate intake to ensure your glycogen stores are full for race day. Though you don’t need to go carb crazy as you’ll be tapering, so naturally expending less energy and using less glycogen than you would in a typical training week. Aim for around 10 grams of carbohydrate per kg of body weight. So if you weigh 70kg, you should try and eat around 700 grams of carbs per day.

It’s also important to get to the start line well hydrated, even one percent dehydration can have a negative effect on your performance. Start hydrating around three days before the race. We’d recommend consuming at least two litres of water a day and ensure you’re topping up your electrolytes too.

The night before

The night before the race, aim for a meal that includes carbohydrates and lean protein. Avoid anything too spicy, fibrous or fatty that might give you stomach issues on race day.

If you have any superstitions – for example you feel you race best if you eat spaghetti bolognese on race-day eve – go for it. It’ll help put your mind at ease.


Ironman is notorious for early start times, which makes eating breakfast tougher than you’d think. Ideally you want to eat around two-three hours before the race so set your alarm – you can always go back to bed after – and eat something you’ve practiced in training, such as porridge for slow-release energy. It’s a good idea to add some protein, such as peanut butter, to help with muscle recovery, too.

If you really, really can’t face breakfast at 3.30 in the morning, some triathletes find eating something light around 90 minutes before the race and then filling up on more solid food on the bike leg works for them. Whatever you decide to do, make sure you practice in training to find the best strategy for you. 

Start line

Sip, rather than guzzle, water while you wait for your race to start. This will ensure you’re well hydrated without having a full, sloshy stomach. If it’s been a while since you’ve eaten, you might find an energy gel pre-swim gives you an extra burst of energy. Make sure you practice this in training first though.


After the swim it’s time to start refuelling but some people find their stomach is sensitive when they leave the water, particularly if it’s a sea swim and you’ve had a few mouthfuls of salty waves. 

Practice swimming in a similar environment in training and work out what foods or drinks you can stomach afterwards so you know what works best on the bike while everything settles.


This is where you’re going to consume the majority of your food. It’s much easier to eat on the bike than on other legs, so aim to get in those 60-90g of carbohydrates an hour. You might find it helps to set an alarm on your watch to remind you to consume some fuel every 15-20 minutes or so. 

What you eat is up to you but a mixture of real food, such as bananas, dried fruit and mini sandwiches, energy bars, Veloforte energy chews, gels and sports drinks will help you avoid flavour fatigue. Again, practice in training to see what works for you.

Have two bottles on your bike, one full of water which you can sip throughout the ride, and another with an electrolyte mix to help replace those lost through sweat. The natural fruity flavour of Veloforte’s Vivo, Solo and Attivo electrolyte powders make a nice change from water, too. Vivo and Attivo also pack 22g carbs to help fill that 60g hourly hole.


It’s a lot harder for many of us to fuel on the run leg than the bike. You’re tired, it’s harder to digest food, and, let’s face it, by this stage you might be feeling a bit sick. It’s still really important to get that fuel in to help you cross the finish line, though. 

Energy gels or sports drinks are often the preferred choice on the run as they’re easy to digest and provide a quick hit. You might find it helps to slow down or walk to take on fuel and fluids.


Your nutrition strategy doesn’t stop once you’ve got that hard-earned medal round your neck. You probably won’t feel like eating much but you need to top up those glycogen stores to help you feel slightly more normal and take on some protein to help aid recovery.

A Veloforte protein bar, with the optimal 3:1 carbs to protein ratio, is your friend here as it’s easy to stomach directly after your race. Alternatively, you can reach for a protein shake from Veloforte’s Recovery Range. Make sure you take on plenty of water and some electrolytes, to replace those lost during the event, too.

Aim to eat a good meal no more than three hours after your race. Include carbohydrates for energy, around 20g of protein for recovery and some good fats.

Tempting as it is to head straight for the beer tent, it’s best to avoid drinking too much alcohol as it can slow down the repair of those micro-tears in your muscles and extend the recovery period.

Ironman diet and nutrition for training

We’ve all heard the golden rule, don’t try anything new on race day. So use those months of following your Ironman training plan to hone your eating habits and discover what works best for you.

This is the time to discover which energy sources work best for you for each Ironman discipline. Can you stomach real food on the bike? Does an energy gel give you a pre-swim boost? What can you stomach on the run?

As well as training your body in the months before a race, you’re also training your gut. As you consume calories on the move in training, your gut will adapt to absorbing carbohydrates at high intensities so you’re less likely to suffer from GI issues and tummy troubles.

How to create your Ironman nutrition plan

These guidelines should help you perfect your Ironman fuelling strategy.


Work out roughly how long you’re going to be out on the Ironman course and make sure you have enough fuel to last the duration. Err on the side of caution, anything can happen during an event and if you’re racing at a high intensity, you’ll burn through more glycogen than at a lower level, so it’s best to take more fuel than you think you need – just in case.

Aid stations

Most events will have aid stations on route. These are a good opportunity to fill up your water bottle and there’s usually food or sports products on offer, too.

It’s always a good idea to carry your own fuel so you can take on food and fluids when you need, rather than waiting till the next station.

However, it’s worth finding out what the event offers and try it out in training so you’ll know whether you can top up your supplies at aid stations.

Understand carbohydrate counts

Get to know how many carbohydrates are in your preferred fuels, so you can ensure you’re taking on the recommended 60-90g per hour. A Veloforte energy gel has 22g of carbs per serving for example, while a Veloforte energy bar has around 40g.

Practice fuelling in swim-bike training, too

Most triathletes practise their fuelling on bike-run brick training sessions, but don’t forget about the swim. On race day you’ll need to start taking on fuel once you’re in the saddle so work out what can you stomach when you’re out of transition. You might find your stomach is a bit more sensitive when you get out of the water but settles down further into your ride.


Some triathletes swear by using caffeine during a race and there’s definitely evidence it can help. A study of endurance cyclists found that a combination of caffeine and carbs improved performance by 9% compared to water, and 4.6% compared to carbs alone.

However, some people find caffeine can leave them feeling jittery or doesn’t sit well in the stomach. Veloforte uses slow-acting caffeine from guarana in its products, which can help limit those risks. 

Practice taking on caffeine every so often in training and see how it works for you. You might find taking a caffeine gel – such as Veloforte’s maple, coffee and guarana Doppio which contains 75mg of natural caffeine – towards the end of the run gives you the energy, kick and mental focus you need to get you over the line.


Is the weather where you’re racing similar to the weather you’re used to? If you’ve been training in the UK and your Ironman’s in a hotter country, you’re probably going to need to take on more fluids and electrolytes. Make sure you have enough with you on the bike and run and leave extra bottles in transition. Don’t rely solely on aid stations for hydration, they can sometimes run low.

Where you’re staying

If you’re staying in a hotel the night before the event, scope out what food options are available nearby for dinner and breakfast. If you always eat pasta the night before, reserve a table at the local Italian – if there are lots of other competitors staying nearby you might find all the popular eating spots are booked up in advance. 

It’s likely the dining room won’t be open when you need to eat breakfast so think about something you can make in your room. Is there a kettle to make porridge for example? If you’re driving to the event on the day, can you make some overnight oats and pack energy bars to eat in the car?

If you’re racing overseas, take your energy bars and nutrition with you in case the products you’ve practised with aren’t available at your destination.

Getting started with ironman nutrition

1. Focus on your goals

Before you plan your Ironman nutrition, it’s important to note down your goals. In the training phase do you simply want to fuel your workouts or do you want to lose weight for performance, too?

Think about anything you want to add or remove from your diet or any good habits you want to get into, such as eating protein post workout or making sure you train two hours after breakfast to stimulate race conditions.

2. Create your Ironman diet and nutrition strategy

Think about what you’ll eat before training sessions, during workouts and for recovery, and keep a note of how you feel when you try something new. That way you can discover what works for you and nail your race day nutrition strategy.

Planning out your weekly diet and batch cooking at the weekend means you’re less likely to reach for highly processed foods when you’re tired after a training session and can’t be bothered to cook. You can also ensure you’re taking on enough calories, protein and other nutrients and adapt your plan as you learn more about your body’s requirements.

3. Create your Ironman hydration strategy

Pay attention to thirst, the colour of your wee and monitor how much sweat you lose in hard training sessions by weighing yourself afterwards. This gives you a good idea of whether you’re taking on enough fluids. Experiment with electrolyte drinks on longer rides and runs or keep a bottle by the pool and see what difference it makes to your training.

4. Stock up

Invest in some Tupperware for snacks and meal prep and stock up on different energy bars and gels to see how they work for you.

We don’t think you’ll need to look further than Veloforte’s range of all-natural, real-food bars, nectars, electrolyte powders and chews. They offer carefully balanced, powerful and delicious options for every triathlete’s needs.