What Should Triathletes Eat Before Training?
Getting your pre-training nutrition wrong can ruin a session—energy crashes, stomach cramps, or worse.
But getting it right?
That can take your training to a whole new level.
Today, we’re talking about one of the most common areas triathletes get wrong: their pre-training nutrition.
It’s such an important topic because what you eat before a workout can make or break your performance.
If you fuel correctly, you’ll feel energised and ready to hit your session with full intensity.
But if you get it wrong, you could feel empty, have stomach upset, or even have a session cut short because you can’t continue.
Why pre-training nutrition is crucial
When you exercise, your body relies primarily on two sources of fuel: carbohydrates and fat.
Carbohydrates are the body’s preferred energy source, especially for moderate to high-intensity exercise. They’re stored in your muscles and liver as glycogen and broken down into glucose when your body needs energy.
On the other hand, fat is a much slower fuel to metabolism, or burn for energy. While it plays a significant role in lower-intensity exercise or endurance activities, it’s not efficient enough to power you through harder sessions or high-intensity intervals.
This is why carbohydrates should almost always be the focus when preparing for a workout.
The problem is that glycogen stores are limited. Most people have only enough glycogen to last about 90 minutes of steady, moderate-intensity exercise.
That’s why fueling beforehand is so important, especially for longer or more intense sessions.
If you don’t, you risk running low on glycogen, which can affect the quality of your session and compromise your recovery and long-term progress.
I worked with a triathlete last year, and they had a total light bulb moment about this topic.
We discussed what to eat before training, and I went through the concepts that we’ll cover in the rest of this article.
They suddenly made the connection and said, “So that’s why having something like nuts before my high-intensity training sessions doesn’t make me feel that great!”
I was so pleased that they understood this concept because it allowed everything else to naturally flow.
We then worked on practical solutions to improve their fuelling, which helped them train much better.
And while we’re talking about what to eat before training, you might like to check out this article on how to use caffeine during triathlon races. Your pre-training coffee has another use, too!
The science of pre-training nutrition
When you eat carbohydrates before training, they provide an immediate source of energy and help to stabilise your blood sugar levels. This reduces the chance of starting your session feeling sluggish or low on energy.
The timing of your meal or snack is also critical.
Eating too much, too close to your session, can leave food sitting in your stomach, which increases the risk of gastrointestinal discomfort—especially during activities like running.
On the other hand, eating too far in advance can leave you hungry and without the energy you need to perform.
We’re going to dig into this later I the article, but first let’s talk about how much you should eat before training.
How much should you eat?
The amount of food you need depends on your workout's type, intensity, and duration. For lighter, low-intensity sessions, around 20 grams of carbohydrates is usually enough to keep your energy levels stable.
Aim for at least 40 grams, ideally about 1g of carbs per kilo of body weight for higher-intensity sessions.
For example, if you weigh 70 kilograms and have a high-intensity session planned, you should aim for about 70 grams of carbohydrates beforehand.
This ensures your glycogen stores are topped up and ready to fuel your workout.
What to eat before training?
Generally, the best foods to eat before training are high in simple, easy-to-digest carbohydrates.
These foods provide quick energy and aren’t too hard to digest, meaning they’re less likely to cause stomach upset when training.
All these are great options that could work as a pre-training simple meal or snack
- A banana or a slice of white toast with jam.
- Rice cakes with honey.
- A bowl of low-fibre cereal with a splash of milk.
- Low-fat rice pudding
- A sports drink or gel if you’re short on time or prefer liquid calories.
It’s important to avoid foods that are high in fat, fibre, or protein before a session.
While these nutrients are essential for your overall diet, they’re slower to digest and can increase the risk of stomach discomfort during exercise.
This doesn’t mean you can’t have them, but you need to be way more careful, especially if you already have a sensitive stomach.
Timing your nutrition
Timing is just as important as the type and amount of food you eat.
The key concept is that the longer you have before your training session, the more you should eat, and the closer to the start of your session, the less you should eat.
I’ve included some examples of the sorts of foods you might eat before training so you can get an idea of how this might look in practice.
0-1 Hour: A banana or an energy gel.
1-2 Hours: A bagel with a small amount of jam or honey.
2-3 Hours: Porridge with a small amount of peanut butter and banana.
3-4 Hours: A balanced meal with rice, chicken, and roasted vegetables.
This still works first thing in the morning, too, if you’re short on time or don’t fancy anything particularly big.
Tailoring your nutrition to the sport
The type of training you’re doing also plays a role in your pre-training nutrition strategy.
Running, for example, stresses your digestive system due to its mechanics, so you need to be especially cautious with your food choices. Stick to simple, easily digestible carbohydrates and avoid large meals too close to your session.
Cycling and swimming are generally more forgiving on the stomach, so you can be slightly more lenient with your food choices.
However, it’s still a good idea to avoid foods high in fat or fibre during interval or high-intensity sessions, as they can still cause problems.
Practising your pre-training nutrition
The key to all this is to experiment and discover what works for you while understanding the concepts behind your choices.
What works for one triathlete won’t necessarily work for another, so don’t feel like you have to eat a certain way because someone else does.
The truth is that there are so many options available that could work, you just have to find out what you should go for.
Getting your pre-training nutrition right is one of the simplest and most effective ways to improve your performance and enjoy your workouts.
But if you want to really up your game, you also need to focus on your recovery nutrition too, and I go through recovery nutrition for triathletes in this article.
