Fuelling With Purpose — 30 September 2025


💡 Fuel For Thought

Gut Training: The Workout Most Runners Skip

Do not try anything new on race day” seems to be a well-known rule. However, when it comes to nutrition, many athletes interpret this too narrowly. They’ll test a gel once or twice in training, have no stomach upset, and assume they’re good to go. But tolerating one gel during an easy long run is not the same as fuelling with multiple gels per hour at race intensity.

Your gut is trainable, just like your legs and lungs. Research shows that repeated exposure to carbohydrate during training can increase the gut’s ability to absorb and tolerate higher amounts. Meaning fewer GI issues and more energy when you need it most.

Think of it like rehearsing for a play: you wouldn’t just read your lines once and hope it goes well on stage. You’d practice until the timing, delivery, and flow felt automatic. Race fuelling works the same way.

So instead of just “checking the box” with a single trial gel, build gut training into your preparation. Practice your planned carb intake at your goal race pace, increase gradually toward your target grams per hour, and give your gut time to adapt. This way, your fuelling strategy is part of your training and not a gamble, and you fuel your training with the calories your body needs to adapt and grow stronger as a bonus.


⏰ Quick reminder!

My in-person masterclass is this Saturday!

🗓️ Saturday 4 October - 4:00 pm

📍 361 Degrees Running & Basketball - Subiaco

It’s free to attend, open to all runners, and there are still a few spots left.

Don’t miss this chance to learn practical fuelling strategies you can put into action straight away, plus a live Q&A to get your questions answered.


🚀 Endurance Highlights

1️⃣ Performance effects of caffeine accross different diets

Caffeine is well-documented as a performance enhancer, but does the athlete’s diet change how effective it is? This new study tested elite race walkers during a 3-week training camp where one group followed a high-carbohydrate diet and another a low-carbohydrate, high-fat ketogenic diet. On some sessions, athletes also consumed caffeine (3 mg/kg via caffeinated gum) before a 14 km hill workout.

The findings showed that caffeine improved performance across the board: athletes completed the session 2–3% faster and had sharper cognitive performance, regardless of diet. However, diet still mattered.

The high-carb group consistently trained at higher speeds and improved over time, while the keto group remained slower despite caffeine use. In other words, caffeine can partially rescue performance when carbs are lacking, but it cannot fully replace the benefits of training with high carbohydrate availability.


2️⃣ Maurten bicarb system: First look in endurance testing

Sodium bicarbonate has long been studied as a supplement to help power and sprint-based sports. Recently, the endurance world has started to explore its potential benefits, with Maurten developing the Bicarb System specifically for runners and endurance athletes.

This study tested the product in eight collegiate distance runners, who completed treadmill intervals just above their lactate threshold on two occasions: once with the Bicarb System and once without.

The results showed no significant differences in performance markers such as heart rate, blood lactate, perceived exertion, or respiratory exchange ratio between the two trials. However, an important finding was that athletes did not experience the gastrointestinal distress that is common with traditional sodium bicarbonate supplementation.

While this small study suggests the Maurten Bicarb System may not deliver measurable performance gains in this context, it highlights a promising step toward making bicarbonate supplementation tolerable for endurance athletes. More research is needed to determine its effectiveness under different conditions, intensities, or race scenarios.


🕵🏻‍♀️ Retail Finds*

This week's product review: Fixx Gel X Pro

I'm trying to keep up with the energy gels in the market but it's proving difficult. Here are my thoughts on Fixx's.

Features & benefits

  • Facts per gel (40g): 121 cal, 29.3g carb, 220 mg sodium & 50 mg caffeine (vanilla maple flavour only)
  • Liquid consistency
  • Sweet and salty flavour
  • 1:0.8 glucose - fructose ratio (suitable for high-carb intakes)

Things to keep in mind

  • Grainy texture. I found this a bit odd and didn't feel comfortable finishing the gel. I thought I got an outlier but just saw a couple of reviews online from people saying they got something similar.

Final take

This energy gel is similar to many others in the market. If you like something more liquid with a bit of flavour you may enjoy this one.


👩🏻‍🍳 Kitchen Creations

Cottage Cheese & Yogurt Bowl with Berries

This is a great option to increase your morning protein intake with a balanced breakfast that doesn't need eggs.

You can boost the carbs by adding granola or muesli to it.


I'm committing to sending the most valuable endurance nutrition newsletter. I want to make sure that every piece of content you receive has information that is helpful for you and your journey to achieving your personal best.

Happy fuelling!

Gaby | Endurance Nutrition Specialist

p.s. Perth runners, let’s talk fuelling! Grab your free spot for my in-person masterclass this Saturday. Register here


Gaby Villa

I enable endurance athletes to overcome lack of energy and gut upset so that they can fuel their bodies with confidence and race to their full potential. Subscribe to my weekly 'Fuelling with Purpose' newsletter to receive endurance nutrition insights directly in your inbox.

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