Sprint and Olympic Triathlon Nutrition Plan: Why Fueling Does Matter

Fueling can improve your Olympic or sprint distance triathlon performance. Here’s why you should not ignore it, even though some claim it’s optional.

How many calories does a short distance triathlon burn

Before we talk about what to eat and drink during your sprint or Olympic distance triathlon, it’s interesting to understand what’s at stake energetically.

A sprint triathlon (Swim 750 m | Bike 20 km | Run: 5 km) is likely to take about 1-1.5 hours. You will burn about 1,000 kcal.

The Olympic distance triathlon is two times longer (Swim 1.5 km | Bike: 40 km | Run: 10 km) and will take roughly 2-3 hours. You will burn about 2,000 kcal.

Of course your race duration and intensity will determine how many calories you burn. But more importantly: there’s no need to replace all of those calories during your short distance triathlon. That is because calories are not the right metric to guide your race-day nutrition.

Sprint and Olympic distance triathlon fueling

A 75kg person with 15% body fat has 11kg of fat stored in the body. That equals 99,000 kcal, roughly 50-100x the energy required to finish a sprint or standard distance triathlon.

So why even bother talking about fueling for a short distance triathlon?

Because at short distance race intensity (near lactate threshold intensity) your body relies on carbohydrates as a fuel, not fat. Research shows that during middle distance triathlons, carbs account for 80-90% of total energy expenditure. This will be higher for Olympic distance triathlons, and even higher for sprint triathlons.

Unfortunately — unlike fat — your carbohydrate stores are limited. Depending on your pre-race nutrition and your race intensity, you could empty your carb stores within an hour. Although sprint triathletes might be close to the finish line at that time, Olympic distance triathletes are certainly not.

This is one reason why carbohydrates — not total calories or fat — are the central focus of sprint and standard distance triathlon nutrition plans. Getting your carbohydrate intake right is what keeps you at race pace and prevents slowing down during the run. So how many carbohydrates do you need?

How much carbohydrates do you need?

How many carbohydrates you need to consume during the race depends on how much carbohydrates you burn and how much carbohydrates you have stored in the muscles (also known as glycogen):

Required carb intake = Carbs burned — Carbs stored (glycogen)

A case study shows that a middle distance triathlete burned 240 grams of carbohydrates per hour. Sprint and Olympic distance triathletes race at higher intensities, and are therefore likely to burn even more carbohydrates per hour.

A 1-1.5 hour sprint triathlon will likely require about 250-500 grams of carbohydrate.

A 2-3 hour Olympic triathlon will likely require about 500-900 grams of carbohydrate.

What about our carbohydrate stores?

At Olympic or sprint triathlon intensity, we rely on our glycogen stores. Given the high intensity, we should only consider glycogen that is stored in the active muscles (e.g. not in the liver). The amount differs per athlete (e.g. muscle mass), pre-race nutrition and pre-race taper week.

Although there’s no unambiguous research about the exact numbers of glycogen available in triathletes, it’s probably in the 500 grams ballpark. That means virtually all Olympic distance triathletes perform better when fueling carbs during the race, which is supported by scientific evidence.

It also means that sprint distance triathletes can rely on their glycogen storage IF their glycogen stores are full at the start. But there’s another reason why even sprint triathletes benefit from fueling during the race, which we cover in a bit.

How many grams of carbs per hour during sprint or Olympic triathlon

Sprint distance triathlon

Literature suggests sprint triathletes can improve their performance by consuming 30 grams of carbs (per hour). The obvious reason is that it prevents running out of energy. But that’s not the only reason, since most athletes won’t run out of energy in a sprint.

The other reason is that tasting carbs sends signals to your brain that help you push harder and feel less fatigued, even if those carbs aren’t actually used as fuel. In literature this is referred to as a mouth rinse. Studies show that simply rinsing your mouth with a carbohydrate drink (without swallowing) produces performance improvements similar to drinking. These performance improvements can be more than 5%.

The fact that performance improvements are similar confirms the effect is neurological rather than metabolic.

In practice, a few sips of sports drinks during the bike leg is sufficient for most sprint triathletes. Think 150-250ml total. You don’t need to fuel during the run.

Olympic distance triathlon

Contrary to the sprint triathlon, you risk running out of energy during an Olympic distance triathlon if you don’t fuel. That is true especially if you’re racing at high intensity.

So how many carbs do OD triathletes typically consume during the race?

Literature shows elite-level triathletes consume about 50 grams of carbohydrates (25 g/h) during the Olympic distance triathlon.

Interestingly, carb intake varied a lot between triathletes (± 25 grams in total), with many failing to meet the recommended intake.

So what’s the recommended intake?

Literature suggests Olympic distance triathletes can improve their performance by consuming up to 60 grams of carbs per hour. Since the intensity is so high, you need to focus on carbs that are rapidly oxidized, such as glucose and maltodextrin.

If you’re aiming to finish at a comfortable pace rather than race, 30 grams per hour is sufficient.

Start fueling early in the bike leg. It takes time before carbohydrates enter the working muscle, so don’t wait until you feel low on energy.

Important note: your intake does not necessarily equal your uptake. Just because you can consume 60 grams of carbs per hour, doesn’t mean those carbohydrates actually enter your bloodstream. This is where choosing the right type of food comes into play. And equally important: training your gut. Let’s cover those topics next.

Practical nutrition plan sprint and standard distance triathlon

Now that we know how many carbohydrates we need to consume, it’s time to talk about what exactly to eat and drink. We’ll cover:

• What to eat and drink during a sprint triathlon

• What to eat and drink during an Olympic triathlon

• Caffeine

Here’s your nutrition plan for a sprint triathlon or Olympic triathlon:

What to eat and drink during a sprint triathlon

It’s clear we do not need to eat anything during a sprint triathlon. Therefore, your nutrition plan is simple:

Take a small 500ml bottle and fill it with an isotonic drink. Isotonic drinks contain a carbohydrate concentration that is similar to the concentration of fluids in your body. This allows for a quick uptake. Sip early in the bike leg and drink roughly half of it during the ride.

No food or drinks are required during the run. Assuming you start the race well hydrated, there’s also no need to focus on electrolytes.

What to eat and drink during an Olympic triathlon

Sports drinks are the preferred option on the bike. They deliver carbohydrates and fluid simultaneously, and bottles are easy to carry.

The bike leg typically takes 1-1.5 hours. That means you should aim for (up to) 60-90 grams of carbohydrates. Depending on your (isotonic) sports drink, that roughly comes down to 1-1.5 500ml bottles. Again, start fueling early in the bike leg.

If you’re drinking sufficiently, there’s no need to eat anything solid on the bike.

On the run, gels become the practical choice. They’re compact and easy to carry. Make sure to always take them with water rather than a sports drink to avoid slowing absorption.

A standard gel contains 20-25 grams of carbohydrate. Depending on your run time, 2-3 gels puts you in the recommended 60g/h range. Practice this in training so your gut is accustomed to it.

Electrolytes play a supporting role, particularly in warm conditions or if you sweat heavily. Most isotonic sports drinks already contain sufficient sodium, so additional electrolyte supplementation is usually unnecessary.

If you ever experience GI discomfort, make sure to avoid high carbohydrate intake without gut training, hypertonic drinks, and consuming fibre, fat or protein during the race. And never try anything new on race day.

Caffeine in short distance triathlons

Looking for the most effective legal performance enhancer? Search no further. Caffeine is a well-researched and legal performance enhancer that reduces your perception of effort.

For sprint and Olympic distance racing, timing is everything. Caffeine takes roughly 45 minutes to peak in the bloodstream, so taking it during the race is largely too late. The most effective strategy is to consume caffeine 45-60 minutes before the start.

For Olympic distance specifically, a small additional dose early on the bike can help maintain alertness through the run. But for sprint distance, a single pre-race dose is sufficient.

As with all nutrition: test your caffeine strategy in training before race day. Some athletes are sensitive to caffeine and experience GI discomfort or elevated heart rate at race intensity.

Making nutrition part of your training

In a way, your gut is like your muscles: it is highly adaptable. Research shows that both gastric emptying as well as stomach comfort can be trained. Adaptations that occur appear to be nutrient specific. Regularly consuming carbohydrates during training increases the capacity of intestinal transporters.

In practice: don’t save your race nutrition for race day. Use your training sessions to systematically increase your carbohydrate intake, starting at 30-40g per hour and building toward your race target over several weeks.

Literature

During middle distance triathlons, carbs account for 80-90% of total energy expenditure.

• Gillum, Trevor L et al. “Muscle glycogenolysis and resynthesis in response to a half Ironman triathlon: a case study.” International journal of sports physiology and performance vol. 1,4 (2006): 408-13. doi:10.1123/ijspp.1.4.408 https://pubmed.ncbi.nlm.nih.gov/19124898/

A middle distance triathlete burns 240 grams of carbohydrates per hour.

• Gillum, Trevor L et al. “Muscle glycogenolysis and resynthesis in response to a half Ironman triathlon: a case study.” International journal of sports physiology and performance vol. 1,4 (2006): 408-13. doi:10.1123/ijspp.1.4.408 https://pubmed.ncbi.nlm.nih.gov/19124898/

Olympic distance triathletes can improve their performance by consuming up to 60 grams of carbs per hour.

• Jeukendrup, Asker E. “Nutrition for endurance sports: marathon, triathlon, and road cycling.” Journal of sports sciences vol. 29 Suppl 1 (2011): S91-9. doi:10.1080/02640414.2011.610348 https://pubmed.ncbi.nlm.nih.gov/21916794/

Both gastric emptying as well as stomach comfort can be trained.

• Jeukendrup, Asker E. “Training the Gut for Athletes.” Sports medicine (Auckland, N.Z.) vol. 47, Suppl 1 (2017): 101-110. doi:10.1007/s40279-017-0690-6 https://pubmed.ncbi.nlm.nih.gov/28332114/

Elite-level triathletes consume almost 50 grams of carbohydrates (25 g/h) during the Olympic distance triathlon.

• Cox, Gregory R et al. “Race-day carbohydrate intakes of elite triathletes contesting olympic-distance triathlon events.” International journal of sport nutrition and exercise metabolism vol. 20,4 (2010): 299-306. doi:10.1123/ijsnem.20.4.299 https://pubmed.ncbi.nlm.nih.gov/20739718/

Olympic distance triathletes perform better when fueling carbs during the race.

• McGawley, Kerry et al. “Ingesting a high-dose carbohydrate solution during the cycle section of a simulated Olympic-distance triathlon improves subsequent run performance.” Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme vol. 37,4 (2012): 664-71. doi:10.1139/h2012-040 https://pubmed.ncbi.nlm.nih.gov/22616665/