When it comes to endurance, nutrition during exertion makes a big difference.
It's not just about "taking a gel every now and then": there's a range of grams of carbohydrate per hour that, on average, helps maintain pace, reduce the feeling of being "stuck," and arrive feeling fresher.
These recommendations come from decades of research in sports nutrition, with authors such as Asker Jeukendrup (SpringerLink), Louise Burke (Taylor & Francis Online), and materials from the Gatorade Sports Science Institute , among others.
The idea behind this text is to help you understand:
-
Where do these numbers come from?
-
How to turn this into a practical plan;
-
and how to adapt it to your reality, always respecting individuality and, if possible, with professional guidance.
Important: This content is for educational purposes only and does not replace guidance from a nutritionist or doctor.
Where do these hourly carb numbers come from?
During prolonged exercise, the body primarily uses:
-
glycogen (carbohydrate storage in muscle and liver);
-
The carbohydrate you consume (gels, drinks, food);
-
and fat , especially at lower intensities.
However, glycogen is limited. When it runs out, the sensation is one of a sudden drop in energy and pace.
Studies show that by consuming carbohydrates during exercise, it is possible to:
-
prolong the time until fatigue sets in;
-
better sustain the pace;
-
and finish the race with more control.
That's why researchers started studying how much carbohydrate per hour the body can absorb and use efficiently.
Music tracks recommended by science
In summary, the body of endurance studies suggests something like this (Jeukendrup, SpringerLink; Gatorade Sports Science Institute):
-
Up to 1 hour for the exam.
Even small amounts of carbohydrates can be beneficial, including when used as a mouthwash with a carbohydrate-rich drink during very intense exercise. -
From 1 to 2.5 hours
The general recommendation is 30–60 g of carbohydrate per hour .
This is where the following come in:-
10 km and half marathon races;
-
Olympic triathlon;
-
Long runs or bike rides in that duration range.
-
-
Over 2.5 hours (longer marathons, Ironman, ultras)
The range increases to 60–90 g of carbs/hour , especially when using multiple carbohydrates (e.g., glucose + fructose).
That's because:-
Glucose enters the intestine via a transporter;
-
Fructose, on the other hand.
With this combination, the body is able to oxidize more total carbohydrate per hour, with a lower risk of gastrointestinal discomfort.
-
These numbers are not "rigid rules," but benchmarks for you to test and adjust.
And in practice, what about runners, cyclists, or triathletes?
Thinking about the typical endurance athlete:
-
Half marathon or marathon in around 3–4 hours
A common target is somewhere between 50–70 g of carbs/hour , depending on individual tolerance. -
Ironman, long-distance cycling races, or ultras
Many athletes benefit from 70–90 g/h , provided this is trained in long runs. -
Smaller athletes or those with a history of sensitive stomachs.
They can start at 30–40 g/h and gradually increase, observing the body's response.
Researcher Louise Burke often summarizes this with the idea of "carbs for the work you're going to do" :
Key training sessions and long races require a higher carbohydrate intake, while light training sessions can be done with lower intake, depending on the athlete's overall strategy.
How to calculate your hourly carb goal
1. Look at the duration of the effort.
-
For races or training sessions up to 2.5 hours → consider a range of 30–60 g/h .
-
Above 2.5 hours → consider 60–90 g/hour , adjusting to what you tolerate.
2. Choose a starting point.
-
Have you never used structured nutrition before?
Start at 30–40 g/h for long workouts. -
Are you already used to using gels/drinks?
You can start with 50–60 g/h and evaluate.
3. Turn grams into products.
Example:
-
Target: 60 g/h
-
Gel: 25g of carbohydrates per unit
-
Drink: 30 g of carbohydrate for every 500 ml
Some combinations per hour:
-
1 gel (25 g) + 500 ml of beverage (30 g) + a small supplement (5 g)
-
or 2 gels (50 g) + a few sips of drink (10 g)
What matters is the total per hour , not a specific isolated product.
4. Distribute over time
Instead of trying to do everything at once, it helps a lot to divide it up:
-
For example, at 60 g/h, you could ingest approximately 20 g every 20 minutes.
or -
1 gel every 30 minutes, supplementing with a beverage in between.
This tends to make energy levels more stable and the gastrointestinal tract more comfortable.
We'll even do the calculation for you here.
Why training your gut is essential
Many recent studies show that the gut adapts to carbohydrate intake during exercise. Athletes who include sessions with higher intake (e.g., 60–90 g/h) in long training sessions:
-
They tend to report less discomfort;
-
They are able to use larger amounts of carbohydrates over time;
-
and tend to perform better when they need this strategy in a race.
That's why it's worth it:
-
Choose a few long training sessions in the weeks leading up to the race;
-
Test the same carb strategy you intend to use on the day of the event ;
-
Note what worked and what needs adjustment (volume, frequency, product combination).
Common mistakes (and simple ways to fix them)
-
Starting to eat carbs too late
Ideally, intake begins within the first 20–30 minutes of the test, in small amounts, and continues steadily. -
Use a small amount throughout the entire race.
Classic example: a 4-hour marathon with only 2 gels of 25 g each (total 50 g → approximately 12 g/h).
This is well below the suggested performance ranges. -
Do not include what comes from the drink in your calculations.
Sometimes athletes use gels + drinks + other foods, but don't add up the grams.
Doing this calculation helps you understand if you are at 30, 60, or 80 g/h. -
Testing new products only on the day of the exam.
Whenever possible, try new gels, flavors, and drinks during workouts, especially long runs. -
Ignoring individuality
Some people feel good at 80–90 g/h, others do better at 50–60 g/h.
The goal is to find the ideal point for you , within the reference ranges.
Simple examples of strategies
Half marathon in 1h45–2h
-
Target: 40–50 g/h
-
Possible strategy:
-
1 gel around 30–40 min;
-
1 gel every 1 hour and 10 minutes to 1 hour and 20 minutes;
-
supplementing with small sips of sports drink.
-
Marathon in 3h30
-
Target: 50–70 g/h
-
Example:
-
1 gel every 30 minutes;
-
300–500 ml of sports drink per hour, if well tolerated.
-
Ironman (race in ~10h)
-
Average target: 70–80 g/h on the bike and at the start of the run;
-
A strategy combining gels, a carbohydrate drink, and eventually a light solid food, always tested beforehand in long workouts.
Z2 is here for you!
When you understand how many grams of carbs you need per hour, it becomes much easier to put together a consistent race plan.
The Z2 can help precisely with that:
-
All products with clear amounts of carbohydrates per serving ;
-
We provide educational materials, ebooks, calculators, and sample plans;
-
We encourage each athlete to test and adjust their own training strategy.
In long races, there's no need to guess.
With information, training tests, and the right products, you can achieve an hourly carb intake that works for your body and your goals.
Find similar articles
Alimentação estratégica
