What & When to Eat the Day Before a Triathlon?

Training well requires fueling well, and what you eat leading up to race day can have just as much (if not more) of an impact as what you eat on race day.

But with so much information out there, it can be hard to understand what exactly you should be consuming, so getting it right can be overwhelming.

We’ll break down what to eat in the days leading up to your triathlon and what you should bring with you on the day of the race.

When Should You Eat Before a Triathlon?

Eating the perfect race-day nutrition won’t make much of a difference if you haven’t been fueling properly in the days leading up to the race. Your exact nutritional needs will vary depending on your level of activity, size, gender, and performance goals. If you have certain dietary or health considerations, you should work with a registered dietician to make sure you’re meeting your body’s needs.

However, for most non-professional athletes, a diet rich in whole foods is a great start. This means a focus on vegetables, whole grains, lean protein, healthy fats, and fruit. It’s generally best to avoid too much-processed sugar as part of a regular diet. However, sugar is an incredible substance to consume during a race or training event as the energy can be used immediately.

There are two primary sources of nutrients: macronutrients and micronutrients.

Most micronutrient needs will be met through a healthy diet that incorporates plenty of fruit and vegetables. Some people opt to add supplements to their diet if they find it difficult to meet certain micronutrient goals (such as those living in the northern hemisphere sometimes needing a Vitamin D supplement). However, you should only take supplements as recommended by a registered dietician or if your doctor prescribes them after a diagnosis. Supplements are typically not regulated in food standards or third-party testing, so be wary of falling for a marketing ploy.

Macronutrients are the major building blocks of nutrition, and usually the ones that get the most attention. Let’s go over the difference between the three types and the roles they play. These include carbohydrates (carbs), protein, and fat. Consuming the right amount of these key nutrients can make or break your triathlon performance.


Triathletes should aim to consume 8 to 12 grams of carbs per kilo of body weight each day. The more intense the training, the higher end of the spectrum you’ll likely want to consume. You can eat simple carbohydrates about 30 minutes before training (like a banana), but longer efforts will require electrolyte replenishment (these will often be in the form of bars or gels). (Source – A, Source – B)


Your body can’t store the energy from protein the way it stores energy from carbs, so timing is critical when it comes to this macronutrient. Athletes should try to consume it within two hours of exercise and eat it every 3-4 hours throughout the day (Source).

The general guideline is to eat 2 grams of protine per kilogram of bodyweight


You need to consume fat as part of a healthy, well-rounded diet, but most triathletes will do best when focusing on energy from carbs. Fat should be around 20% to 35% of your daily calories. You can experiment with different ranges to discover how your body functions best but always speak with a registered dietician before attempting a significant change. (Source)

What Is the Best Meal to Eat the Night Before a Race?

The day before a race is definitely not the time to try an exotic new recipe or to completely overhaul your standard diet. As long as you’ve been eating well in the days leading up to the event (and ideally throughout your entire training period), you’ll be set up for success. But what specifically should you eat the night before?

It’s important to make sure you have plenty of carbohydrates in your system for the effort ahead. This means eating the standard 8 to 12 grams per kilogram of body weight you’ve been consuming during regular training. If you’ll be doing a race that will take longer than 90 minutes (like Olympic distance, 70.3, or Ironman), you can consider carb-loading the night before. You’ll likely need a registered sports dietician to help you dial in exactly what this would look like for you, as it varies depending on training.

Unfortunately, eating too many carbs can backfire and cause bloating – and your body may not even be able to utilize all of the carbs

A good range is a dinner of 60-80 grams of carbs, plus some protein and fat. This could look like spaghetti with a side of chicken breast and a side salad with a drizzle of olive oil. Or you could opt for a bowl of rice topped with tofu, vegetables, and avocado.

What Is the Best Food to Eat During a Race?

First, it is important to never try anything new on race day. You’ll want to make sure you incorporate nutrition and fueling as part of your training plan. For example, a lot of athletes like to consume energy gels as a quick source of carbs and sugar. But if you’ve never had one before, you might be surprised by the consistency and unable to get it down, leading to a bonk.

Try to plan for 30-90 grams of carbs per hour during your race. If you find yourself needing the higher end of the spectrum (think over 60 grams of carbs per hour), you can experiment with different sources of carbohydrates like glucose and fructose. They’ll be absorbed by your body differently so the energy you feel (if any) will vary. This is another reason why it’s important to really dial in your nutrition before you even step on the track (or in the water).

You can reach your energy goals in various forms. This includes the aforementioned energy gels, plus energy blocks, and sports drinks. It may also include more standard foods like granola bars, bananas, maple syrup, Coke, or small sandwiches. Experiment until you find what sits in your stomach the best.

From our humble experience ( Check our bio for more), we found GU Roctane Energy Gel (Amazon Link) complemented with Stealth Energy Gel and Some other solid food every now and then to be the best combination for the body and more accurately the stomach. The GU gel version with caffeine gives that boost and the stealth Gel is just very gentle on the stomach which keeps you going but it’s hard to get your hand on some. As a substitute for Stealth, I would recommend trying SIS GO Isotonic Energy Pack (Amazon Link)

A major part of nutrition will also be your fluid intake. You can’t rehydrate the day of a race if you’ve been dehydrated in the days leading up to it, so make sure you’re drinking plenty of water beforehand. You’ll also need to have plenty of water while doing the race, but it’s equally important to consume sugar and electrolytes.

If you are looking for an electrolyte source, we highly recommend Nuun tablets Energy (Amazon Link). Aside from the nice flavors offered, Nuun is among the few, if not the only electrolyte tablets that have caffeine in them. We have tested it for a while and just couldn’t find any better substitute.

Things to Keep in Mind

Every athlete will have different nutritional needs for a race, so there’s truly not a one-size-fits-all approach that will work for everyone. Make sure to listen to your body and monitor your performance over time to find the food and fluid combination that works best for you.

Aprill Emig

Based out of Duluth, MN Aprill loves to write about the outdoors, education, and all forms of adventure. You can find her mountain biking, running, or playing roller derby.

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