Hello Runner,
Welcome back to your weekly moment of endurance nutrition!
Happy Weekend!
How was your week?
I had a great week! I went for a run with a friend who hadn’t run in a long time because of a fracture she suffered last year, attended a VERY interesting workshop on nonverbal communication, met new people, and did some networking.
Despite the heat (which seems to just keep getting worse), I’ve been able to train outdoors, but I’ve been heading out really early.
Also, I’m getting ready for a trip next week, and I’m really excited about it. I’ll be away for a while, but the newsletter, work, studies, and training will continue as usual.
Today's topic is carbmaxing. It's a trending topic that has gained momentum since the London Marathon and the most recent Ironman races. Is carbmaxing only for the elite or for amateurs too? Should you be carb-maxing on your runs?
If you've spent any time on social media lately, you've probably seen elite marathoners and triathletes talking about taking in 90, 100, or even 120 grams of carbohydrates per hour during races.
Perhaps you, as a marathon runner, might think: "Should I be doing that too?"
The short answer is: maybe, but not because elites are doing it.
When you run, especially at marathon pace or during a long run, your muscles rely heavily on carbohydrates for energy.
The challenge is that your body's carbohydrate stores (called glycogen) are limited. As those stores become depleted, you'll likely notice some signs, and that's where fueling during your run comes in.
By taking in carbohydrates while you're running, you can help maintain your energy levels, preserve your body's glycogen stores, and support your ability to keep running at your planned pace for longer.
If you've been reading my newsletter for a long time, I'm sure you already know this.
What do current recommendations say?
Based on current sports nutrition guidelines, here's a good starting point:
Runs under 60 minutes
- Most runners don't need carbohydrates during the run.
Runs lasting 1–2.5 hours
- Aim for 30–60 grams of carbohydrate per hour.
Runs lasting more than 2.5 hours
- Around 60–90 grams per hour from a mixture, at roughly a 2:1 glucose: fructose ratio.
But there's an important detail that often gets left out of the conversation...
Your gut needs training too
Very few train their digestive system.
Yet your gut is just as much a part of race-day performance as your legs.
The ability to comfortably absorb and use carbohydrates while running is something that improves with practice.
The more consistently you practice your race-day fueling during long runs, the better your digestive system becomes at handling it.
If you want to increase your carb intake during your runs, there’s no magic formula; you have to train your gut, no matter what.
So... is carb-maxing during runs only for elite athletes?
It depends.
There is currently little evidence that 120g/h is superior to 90g/h, so the highest intakes are best treated as experimental until better studies are available.
To give you an idea, Sabastian Sawe (winner of the 2026 London Marathon, who finished the race in under 2 hours) spent 12 months working with scientists from Maurten, testing to understand his energy expenditure, how much carbohydrate he could absorb, and logging his food intake to design both his race strategy and his training diet. He had a plan built entirely around him.
In another instance, I’ve seen amateur runners (who don’t suffer from digestive issues) consuming 100g/h during long runs. They always do this under professional supervision, training their digestive system during every long run, and building up gradually.
Why copying elite athletes can backfire
Without gradually training your digestive system, large carbohydrate intakes can lead to:
Bloating
Nausea
Stomach cramps
Diarrhea
Vomiting
Feeling too full to keep eating or drinking
Ironically, trying to fuel "perfectly" can actually make it harder to perform your best.
That's why successful race nutrition is the best way to find the highest amount that your body can comfortably tolerate and use.
STRATEGY
How to build your fueling strategy
The best option is always to consult with a sports nutritionist who specializes in running; they will not only develop your race nutrition strategy but also create a meal plan for your training sessions, including proper timing and strategies to help you train your gut.
But here are a few practical guidelines to follow when creating your nutrition strategy for your training:
✅ Match your fueling to the length and intensity of your run.
✅ Practice your race nutrition during long training runs
✅ Train your gut during your long runs*
✅ Remember that your fueling plan should evolve as your training and goals evolve
*Look for the email in this newsletter that explains how to train your gut
And here’s a good step-by-step guide to follow when creating your nutrition strategy for the race (half marathon or marathon):
✅ Determine how long it will take you to run the race based on your pace
✅ Follow the recommended hourly carbohydrate intake, as listed below, based on your estimated race time, to decide what to bring to the race
✅ Use the same gels, drinks, food, or chews you used in your training so there are no surprises.
✅ If you're taking gel, number them with a waterproof pen so you don't get confused about which one to take next.
✅ Always bring extra supplements to a race; the gel might not open, it might fall on the ground, you might need more, etc.
Before you even think about consuming large amounts of carbs during a race, keep in mind that everything (hydration, digestion, training, etc.) has to be in perfect order.
There’s no point in stuffing yourself with carbs if your body doesn’t know how to use them.
A good fueling strategy for a race must provide enough energy for you to perform well and finish the race strong.
Remember, the strongest race-day nutrition plans aren't built the night before the race.
Product of the Week
This week's Product of the Week is the Precision Fuel 90 Gel.
This is for long-distance runners who are already used to consuming larger amounts of carbohydrates.
I found the packaging very convenient for carrying and consuming, much better than having to carry a bunch of gels just to reach 90g.
It contains no artificial ingredients and is made with a 2:1 mixture of glucose and fructose.
Track of the Week 🎧️
This week's Track of the Week is a relatively new song I discovered this week. I loved it. It's the kind of song you listen to at the end of a long run to give you that extra boost of energy you need.
I’ve chosen So Good (feat. Kuuda) by CamelPhat, Josh Gigante, Kuuda
Any questions or something you would like to share, drop me an email
Wishing you a great weekend and week ahead!
Here’s to health and good runs⚡️
Ana Paula Alonso