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Complete Guide to Triathlon Nutrition Strategies For Racing and Training

Zach Nehr

Nutrition is the fourth discipline of triathlon – you may have heard that phrase before, and that’s because it is entirely accurate. Triathlon nutrition takes months planning, training, and execution on race day. Without proper nutrition, you won’t even finish your triathlon, let alone set a PR. 

This article will tell you everything you need to know about triathlon racing and training nutrition. We’re going to discuss every calorie you should consume during a triathlon workout, whether it is a high-intensity bike session or a low-intensity endurance run. 

First, we’ll run through triathlon racing and nutrition training basics. Specifically, we will discuss nutrition timing in triathlon, what foods to eat, and when to eat them. 

Next, we’ll help you create a nutrition plan for triathlon training and racing, plus the critical differences for planning an Ironman nutrition strategy. We’ll also talk about the differences between fats and carbohydrates and how you can use each as a fuel source. 

In the second half of this post, we’ll talk about the differences in nutrition for speed workouts versus endurance workouts. There is even a handy chart that we’ve created to demonstrate the difference between high fat burners and low fat burners in triathlons.

Lastly, we’ll identify the most common mistakes in triathlon nutrition, including fasted training and the difference between body weight and body composition. 

Triathlon Nutrition Basics

Triathlon nutrition does not need to be complicated. It is all about having a system to fuel your workouts day in and day out. 

Without proper fueling, you will leave fitness on the table every workout. The saying goes both ways, as you will always underperform on race day without a proper triathlon nutrition plan. 

What we’ll cover below is a complete system for triathlon nutrition. Here are a few of the highlights:

  • Use our triathlon nutrition calculator to find your exact caloric needs
  • Eat a full meal 3-4 hours before a training session or race
  • Fuel with carbohydrates before and during high-intensity workouts
  • Fuel with fats before and during low-intensity workouts
  • Only consume solid foods on the bike
  • Practice consuming energy gels, sports drinks, and electrolyte mixes in triathlon training and racing

As we will discuss below, there are key differences between triathlon training nutrition and triathlon race nutrition. 

You should begin practicing your triathlon race nutrition ten weeks ahead of your goal race, which gives you plenty of time to train your gut, try new fueling strategies, and perfect your race day nutrition plan. 

First, plug your numbers into our triathlon nutrition calculator to find exactly how many calories you should consume during your triathlon. 

Timing of Triathlon Nutrition 

man in black and white long sleeve shirt smoking cigarette
Triathlete consuming nutrition before the swim leg

Many athletes know precisely what to eat and what foods work best for them in training and racing. But they don’t know when to eat

The timing of your triathlon nutrition is as important as the quality of it. Start eating too late, and you are destined to bonk or run out of energy. If you go two hours without eating in the middle of an Ironman, you will suffer the same fate. 

Triathlon nutrition timing begins hours before the race with a carbohydrate-heavy breakfast. We recommend eating breakfast 3-4 hours before the start of the race and then consuming a sports gel within 20-30 minutes of the start. 

Once you’re onto the bike leg, aim to consume calories every 17-28 minutes, if not more often than that. Refer to the triathlon nutrition calculator to see exactly how many calories you should consume each hour. With some quick math, you can determine the calories you should consume every 17-28 minutes. 

Stick with that nutrition schedule through the bike and into the run, with your last piece of solid food consumed with 30-45 minutes remaining in the bike leg. You should keep taking in liquid or gel calories every 17-28 minutes. The 30-45 minute window is for solid food only, providing your stomach enough time to digest the solids so they aren't bouncing around during the run.

Keep consuming calories on the run all the way to the finish line. Not literally, but don’t be afraid to have another energy gel with five minutes to go, just in case. 

What to Eat and Drink for Triathlon 

There are a few staple foods and drinks that you should be consuming during a triathlon: 

  • Sports drink
  • Energy gels
  • Energy bars
  • Electrolyte drinks
  • Water

For most triathletes, these foods and drinks are the easiest on their stomachs, provide the best portions of calories and carbohydrates, and are the most reliable foods and drinks across different weather, terrain, and distances. 

You can also use these products for training as they are easy to carry on a long training ride, for example. 

It is best to avoid solid foods during a triathlon. You can try eating solid foods in training when the intensity is lower and especially when you have time to stop and eat. Liquid calories are best for racing as they can be consumed and digested very quickly.

In training, it is best to focus on consuming whole foods before your training sessions. You should aim to consume a full meal 3-4 hours before your training session, with a different proportion of nutrients depending on your workout. 

We’ll dive into more details below, but the key to pre-workout fueling is consuming more carbs before a high-intensity workout and more fats and proteins before a low-intensity workout. Fruits and vegetables are always good, whereas peanut butter should be saved for your low-intensity days. 

Recovery Foods and Drinks for Triathlon

woman in white crew neck t-shirt holding red plastic cup
Athlete creating a recovery shake

After each workout, it’s essential to refuel with a mix of carbs and protein immediately post-workout. It is best practice to have a recovery shake or meal within the two hours following your workout. Still, some research suggests that a 30-minute post-workout window is even better. 

The reason that you need to refuel right away is that you need to refill your glycogen stores. These stores give us energy throughout the day and power our muscles through exercise. When you completely deplete your glycogen stores, that is known as bonking. Speaking from experience, it’s not fun. 

Recovery foods and drinks should also contain protein which assists muscle repair post-workout. Your post-workout shakes or meals should include a mix of carbs and proteins, plus vitamins and minerals.

After high-intensity training sessions, focus on consuming more carbs to refill your glycogen stores. Following a low-intensity training session, focus on consuming fewer carbs and more protein and fat to help repair your muscle fibers. 

Fueling for the Swim Leg 

toast bread with blueberry on black plate
French toast with bananas and blueberries

You won’t be able to consume anything during the swim leg of a triathlon. However, this means that your pre-race fueling is critical. Because once you’re in the water, there’s nothing you can eat until you’re finished with the swim. 

We recommend eating a breakfast filled with carbohydrates 3-4 hours before the start of your triathlon. Focus on consuming carbohydrates in this meal, such as oats, cereals, or rice. This might mean waking up at three or four in the morning, but you can always go back to bed after downing a quick meal. 

Before the start of your race, you should have a sports gel 20-30 minutes before the start. This will give your body plenty of time to process the carbohydrates and fuel you for over an hour until you’ve finished the swim. 

Fueling for the Bike Leg 

Athlete being handed nutirion on the bike leg of a triathlon

The bike leg of a triathlon is the best time to eat solid food during a triathlon. It’s impossible to eat solid foods during the swim, and forcing solid foods down during a run can be uncomfortable, to say the least. 

On the bike, focus on nailing your nutrition strategy with calories and carbs with a mix of solid foods, sports drink, and energy gels or chews. You don’t necessarily need to consume solid foods, depending on personal preference. If your gut and digestive system can handle all the calories you need from liquids and gels, you don’t need to force yourself to eat solid foods. 

You can increase your caloric intake by 10% on the bike as this is the easiest time for your body to process extra fuel. It is likely that you won't be able to consume as many calories on the run as you're able to on the bike, so if you can execute the 10% calorie surplus plan on the bike, then you can drop your calorie goal on the run by 10% as your stomach settles and you begin to approach the finish. 

Fueling for the Run Leg 

Once you enter the run leg of your triathlon, you should only be consuming energy drinks, sports gels, water, and electrolyte mix. It can be nearly impossible to consume solid foods at this point of the race, so make sure you train your gut and digestive system with liquids, gels, and water. 

Again, focus on hitting your nutrition goals based on calories and carbohydrates throughout the run leg. 

The best practice is to consume sports gels and electrolyte mix as your source of energy during the run leg. This provides the best ratio of carbohydrates and liquids while being (relatively) easy on your stomach. 

If you’re training for a marathon instead of a triathlon, we have a complete guide for you here.

Dealing with Stomach Issues During a Triathlon

It is very common to have stomach issues crop up during a triathlon. Between the intensity, volume, weather, and nutrition, it can be a lot for your stomach to handle during a triathlon. These issues are most likely to come up during the bike leg or run leg of a triathlon when you are taking in the most calories.

With our recommended nutrition strategy, you should be taking in a mix of liquid calories, gels, chews, electrolyte drinks, and water. We don't recommend having an all-in-one nutrition strategy where you are taking in all of your calories from one drink or source.

If your stomach starts to get upset, switch to drinking water instead of electrolyte mix. Keep up with the energy gels as best you can, as these will provide the necessary carbs and energy to get you through the rest of the race. 

Switching to water will help reset your stomach by balancing the osmolality. It shouldn’t be long before you feel better. When your stomach is back to normal, switch back to electrolyte mix along with your sports gels. 

We recommend separating your drinks (electrolyte mix and water) from your calories in case you become extra thirsty and start drinking more.

This is also why we don't recommend using an all-in-one nutrition strategy. If your stomach gets upset and you switch to water, you'll no longer be taking in any calories and the bonk becomes imminent.

Triathlon Nutrition for Different Types of Workouts

Triathlon nutrition is not all created equal. You’ll need to adjust your nutrition strategy based on the length and intensity of your workouts. Adjusting for the duration is self-explanatory, and the differences will be apparent in our nutrition calculator at the beginning of this post.

However, there are crucial differences in the proportion of carbs, fats, and proteins that you need to adjust for each workout. 

Nutrition for Speed Workouts

Fueling for speed workouts is all about carbohydrates – carbs, carbs, and more. You don’t need to stuff yourself like at Thanksgiving dinner. Instead, focus on the proportion of carbohydrates you eat before and during your speed workout. 

Speed workouts are typically short, high-intensity workouts designed to improve your speed over a given distance. Given the high intensity, it can be hard to digest solid foods during a speed workout, so this is an excellent opportunity to practice fueling with sports drinks, energy gels, and electrolyte mixes. 

Most speed workouts are 60-90 minutes long, which means that you technically have all the stored carbohydrates you need to complete the workout. However, this assumes that your glycogen stores are full at the beginning of your workout. That means you need to fuel your speed workout with a carbohydrate-rich meal before the session. We’ll dive into the specific number of carbohydrates below as we begin crafting your triathlon nutrition plan. 

woman in black and white stripe tank top and black shorts sitting on brown wooden fence
Athlete consuming nutrition during a bike ride

Nutrition for Endurance Workouts

Endurance workouts are defined as low-intensity workouts that are strictly below Zone 2. These workouts should be fairly easy and done at a ‘talking pace’ on the bike or the run. 

Check out our guide to Zone training for triathletes here.

The focus of endurance workouts for triathlon is learning to burn fat as fuel. To burn fat as fuel, your body should be relatively low on carbohydrates. This does NOT mean that you should enter each endurance workout depleted. Instead, you should be fueling with fats and proteins instead of grams of carbohydrate. 

Before an endurance workout, focus on fueling with minimal grams of carbohydrate such as berries or bananas. This will stabilize your blood glucose levels while still using fat as your primary fuel source. 

As long as you strictly exercise below Zone 2, you should never need to worry about bonking. When you’re using fat as a fuel source, you are burning through some of the tens of thousands of calories of fat stored in our bodies. By contrast, most humans can only store 2000-3000 calories’ worth of carbohydrates at once. 

Using fat as a fuel source is one of the most significant determinants of triathlon performance, especially for a long course or Ironman triathlete. Below, we’ll dive into the math to see why high fat burners outperform low fat burners. 

Nutrition for Race Workouts

The last category of the training session we have is race-specific workouts. These are workouts designed specifically for your goal race and typically completed once per week. 

Race workouts involve race pace intervals and are the perfect opportunity to practice your race-day nutrition. This is the exact effort you will be swimming, riding, or running at on race day, so knowing what your body and your stomach can handle at such an effort is important. 

One of the biggest mistakes a triathlete can make is not practicing their race-day nutrition strategy in training. Make sure you nail your nutrition targets (caloric intake, number of carbs, etc.) in training to avoid trying something new on race day. 

Athlete on a training bike ride

Triathlon Nutrition for High Fat Burners vs. Low Fat Burners

Below, we’ve put a table together to demonstrate the difference between high fat burners and low fat burners in triathlon training and racing. This example looks at two different athletes competing in an Ironman and finishing in a time of 12 hours. 

Both athletes will burn the same number of calories (in this simplified example), start with the same number of stored calories, and consume the same number of calories throughout the race. 

Using what we know about fat and carbohydrate metabolism, we can see exactly how many more calories from fat the high fat burner uses compared to the low fat burner. By the end of the race, the low fat burner has a surplus of over 1,156 calories, putting them at great risk of bonking or ending up with a DNF. 

MetricHigh Fat BurnerLow Fat Burner
Calories burned12,00012,000
Calories stored at the start2,5002,500
Calories consumed (assuming 60g of carbs per hour can be ingested)2,8802,880
Calories burned from fat1.2g/min x 9 calories/g x 12hrs = 7,7760.4g/min x 9 calories/g x 12hrs = 2,592
Total available calories13,1567,972
Surplus (shortfall)1,156 surplus(4,028) shortfall

Triathlon Racing and Training Nutrition Plan

You can see the pieces coming together in the above paragraphs. We will put the puzzle together in our triathlon racing and training nutrition plans. First, we’ll start with training. Second, we’ll help you create a triathlon race nutrition plan. And finally, we’ll explain some small differences in creating an Ironman nutrition plan. 

Fueling for Triathlon Training

Start by returning to our triathlon nutrition calculator and noting your target number of calories consumed. 

Once we break down our nutrition strategy, we need to divide our strategy into three different categories of workouts: speed, endurance, and race. 

Speed Workouts Nutrition Plan

Fuel your speed workouts with 30-50 grams of carbohydrates before the workout. That could be a bowl of cereal, toast, or pancakes. Anything rich in carbohydrates to fill up your glycogen stores before the workout. 

As long as your speed workout is less than 90 minutes, you don’t need to consume additional calories. However, we recommend having a sweet-tasting drink that will activate the neuromuscular system and give you a kick each time you take a sip. 

person climbing concrete stairs
Man running up stairs

Endurance Workouts Nutrition Plan

When completing an endurance workout, your nutrition goal should be to control your blood glucose levels. You shouldn’t be fasting or in ketosis. Instead, your goal is to burn as high a percentage of fat as possible.  

Before an endurance-building workout, consume a meal that is high in protein and fat while low in carbohydrates. For example, you could have an omelette, peanut butter, meats, seeds, or nuts. 

Suppose your endurance workout is longer than 90 minutes. In that case, you should be fueling with the same high-fat and high-protein foods at a rate suggested by the triathlon nutrition calculator. Just plug in the workout, time, and details, and you will get the target number of calories to consume.  

Race Workouts Nutrition Plan

6-10 weeks before your goal race, you will start doing race-specific workouts once per week. These efforts should be fueled in the same way as you will fuel your race day efforts, but with some slight modifications. That means a high amount of carbohydrates before and during the workout. 

When you first start your race-specific workouts 6-8 weeks before your goal race, your should start at the low end of the nutrition calculator when it comes to taking in your calories. You will gradually increase this amount each week to help train your gut while also training your race-specific fitness.

At the peak of your race-specific training, you may actually be consuming more calories than the target from the calculator. On race day, you'll actually be able to drop your calories down, and your stomach should be able to handle the race-day calories comfortably compared to what you consumed in training.

Similarly to how you increase your training load over time, you should focus on increasing the number of carbohydrates that you can consume each week. 

Another key point is that you should consume a high-carbohydrate snack before your race-specific workout. Aim to consume a muffin or bowl of cereal, for example, 30-60 minutes before your race workout, to ensure that your glycogen stores are completely topped off. 

During your race workout, consume the exact amount of calories that our triathlon nutrition calculator suggests. These calories should come from mostly carbs, such as sports gels and energy drinks. 

Specifically, you should aim for a high percentage of carbohydrates consumed during these workouts. Our nutrition calculator will provide your target number of calories to consume, but you can also narrow it down by calculating the grams of carbohydrate per hour to consume.

In everyday life, you may be consuming 3-10 grams of carbs per kilogram of body weight per day. However, as a triathlete, your carbohydrate requirement will be much greater on high-intensity training days and race days. These days, a triathlete should aim for 8 to 12 grams of carbs per kilogram of body weight per day.

For example, a 70 kg triathlete may be consuming 2,800 calories per day. At 8-12 CHO (carbohydrate) grams per kilogram, this athlete should be aiming to consume 560-840 grams of carbohydrate per day.

Remember that this goal doesn't need to be met every day. The 8-12 grams of carbs per kilogram of body weight per day are reserved for big training days, high-intensity training sessions, and races.

Fueling for Ironman Triathlon

In truth, there aren’t that many differences between an Ironman triathlon fueling plan and a triathlon nutrition plan. The main difference is that Ironman is significantly longer than other forms of triathlon, and it can take upwards of 12 hours for many triathletes. 

When it comes to your race day nutrition, the timing and foods should be the same as your typical triathlon nutrition plan. You can get all of these numbers from the calculator above. 

However, the biggest difference in Ironman triathlon nutrition is the volume of food that you will be consuming. When you’re exercising for upwards of 12 hours, you will be consuming thousands of calories (while exercising) throughout the day. That means that you really need to train your gut. Practice your race day fueling in training because you don’t want your stomach to turn with 15 miles to go in the marathon. 

group of people wearing blue and yellow helmet
Athletes ready to start the swim leg of a triathlon

Quick Tips for Triathlon Race Nutrition 

  • Aim to consume 1 bottle per hour on the bike and during the run
  • If you are thirsty, then drink slightly more
  • If you are burpy or your stomach is feeling upset, switch to water to reset the osmolality in the stomach
  • Consume a light electrolyte drink throughout your session
  • Use HotShot or CrampFix to combat cramps

Common Mistakes in Triathlon Racing & Training Nutrition

While it may appear simple on the surface, triathlon racing and training nutrition can be hard to perfect. Life gets in the way, you start traveling, or your eating schedule doesn’t line up with your work schedule. It’s easy to let your nutrition slide, but believe me, you will immediately notice the differences in your workouts and energy levels. 

Proper fueling is one of the keys to success in endurance sports, yet there are some basic principles that you can easily get wrong. Here, we’re going to cover some of the pitfalls of triathlon racing and training nutrition, how to avoid them, and what to do instead. 

Fasted Training

silver fork and knife on plate
Empty plate with a sad face

The topic of fasting has come to the forefront of the health and fitness industry in the last decade. There are countless studies, podcasts, and articles on the benefits of fasting, but there is still much that is unknown. 

Crucially, most of these studies involve members of the general population, not endurance athletes. For those getting into triathlon, aiming for a PR, or trying to compete at their very best, fasted training is NOT a good option. 

The best way to make the biggest fitness gains is to fuel your training and get stronger. 

Sure, you could shave off half a percent of body fat with weeks of fasted training – or you could get 5% stronger by fueling your workouts and growing your muscles. 

Ideal Body Weight for Triathlon

Many athletes, especially endurance athletes, struggle with their body weight and body image. For years, we’d seen the best endurance athletes in the world looking rail-thin. But the trend is changing, and the best triathletes in the world are now strong and muscular. They’ve realized that being strong is better than being skinny. 

It is impossible to guess your ideal body weight for a triathlon, and perhaps there is no answer. We’ve seen triathletes set PRs at 150 lbs, 165 lbs, 175 lbs, and everything in between. Because of the tri-sport nature of triathlon, you can always be better at one discipline and worse at another. 

The key is to NOT focus on your body weight, and rather, focus on your performance. Fuel your workouts using our nutrition calculators above, and your ideal body weight will reveal itself. Remember that a kilogram of body weight won’t determine your performance either way. Focus on proper fueling and consistent training, and you’ll be faster than ever, regardless of what the scale says. 

Body Composition versus Body Weight

After mentioning body weight, we also need to talk about body composition, which is the proportion of tissues in your body, specifically fat, muscle, bone, and water. 

Body composition will tell you your body fat percentage, the amount of muscle that you carry in different areas of your body, your bone mineral density, and more. In general, body composition is a much better metric for endurance athletes to track compared to body weight. 

Body weight doesn’t tell us how fit or strong we are. Did I just gain 5 lbs of fat or 5 lbs of pure muscle? Your body weight won’t tell you the answer, but your body composition will. One will make you significantly faster, while the other could make you slower. 

Instead of trying to lose weight, focus on improving your body composition, which means more muscle and less fat. You shouldn’t need to diet in order to achieve your body composition goals. Instead, the results will come from consistent training and proper fueling. 


Triathlon racing and training nutrition is simple but not easy. You’ve got your numbers from our triathlon nutrition calculator, so you know exactly what you need to consume in racing and in training. 

Focus on carbohydrate fueling before and during high-intensity training sessions and races, and fat fueling (and burning) during low-intensity training sessions. 

Use the exact same foods, gels, and drinks in training as you will on race day. This will train your gut to take in and process many grams of carbohydrates so that you won’t have any surprised halfway through your marathon. 

Come into your training and racing with a plan, and there will be nothing new. Remember to fuel your workouts and focus on getting stronger rather than losing weight. With a proper triathlon racing and training nutrition strategy in place, you will be well on your way to setting a PR in your next triathlon. 

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Zach Nehr
Zach Nehr

Zach has a degree in Exercise Science and Psychology. He is a certified coach, Cat 1 cyclist, and is a freelance writer having been published in many of the worlds largest endurance sports publications.

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