💡 Fuel For Thought

Your fuelling strategy isn't a brand name

When I ask athletes about their race-day nutrition strategy, many answer with a brand name: “I used X gels,” or “I tried X drink.” Unfortunately, products aren’t strategies. And when it comes to ultra-endurance, no single gel, bar, or bottle can cover everything your body needs over hours (or days) on your feet.

That’s why so many nutrition plans fall apart, not because you picked the “wrong” product, but because you were relying on labels instead of building an actual plan.

Two athletes can swear by completely different fuelling approaches and both perform exceptionally. Why? Because the best nutrition isn’t about finding the perfect product, it’s about discovering what your gut can handle, how your energy shifts over long efforts, and what keeps you steady when the miles get rough.

And yes, building that kind of strategy is more involved than grabbing whatever’s on sale at the expo.

It means noticing your patterns, testing combinations in real training conditions, and learning how your gut responds to stress, temperature, pacing, and fatigue. It’s part science experiment, part self-awareness, and part patience. However, the payoff is huge: once you understand what your body needs, fuelling stops feeling like guesswork and becomes a reliable foundation for performance.

The reward is a race plan you can trust.

🚀 Endurance Highlights

1️⃣ How underfuelling disrupts your hormones

Underfuelling continues to be recognised as a frequent challenge among endurance athletes, with serious consequences for both health and performance known as Relative Energy Deficiency in Sport (REDs) syndrome.

​This new paper proposes a compelling hypothesis: when low energy availability is combined with a low-carbohydrate daily diet, the risk of developing REDs may be amplified through a specific hormonal pathway. The authors suggest that this combination increases cortisol levels, which then disrupts thyroid hormone production and conversion, particularly lowering T3, a key hormone for metabolism, recovery, and reproductive function.

According to the model, a persistent low-T3 state may be one of the core drivers behind the hormonal and physiological symptoms seen in REDs, from reduced testosterone and oestrogen to impaired training adaptation, lower metabolic rate, increased fatigue, and higher risk of illness.

This suggests that adequate energy and carbohydrate intake, both in amount and timing, play a crucial role not only in fuelling performance but in protecting hormonal health.

If you prefer some lighter reading, Outside's columnist, Alex Hutchinson recently wrote a great summary talking about this. You can read it here. ​

2️⃣ The role of magnesium in sleep and sleep disorders

Magnesium has become a popular supplement for better sleep, and this new narrative focused on the mechanisms behind magnesium and sleep regulation. ​

Magnesium is involved in hundreds of processes in the body, including muscle relaxation, nerve function, melatonin production, inflammation control, and the body’s internal clock, all of which influence how well we fall asleep and stay asleep. When magnesium levels are low, the nervous system becomes more excitable, inflammation increases, and melatonin production can be disrupted, making restful sleep more difficult.

The researchers also reviewed evidence across different sleep disorders, and found that magnesium supplementation may improve sleep quality in several groups, particularly older adults and those with insomnia or restless legs–related sleep disruption.

Overall, magnesium can support better sleep, but it’s not a magic fix. Its impact depends on your baseline magnesium intake, your overall diet, and the type of sleep problem you’re dealing with. Meeting your basic nutrient needs and building good recovery habits comes first, magnesium can be a helpful addition if sleep is still a challenge.

🕵🏻‍♀️ Retail Finds*

This week's product review: Revvies Energy Gelly

Marathon training has made it easier for me to test a new energy gel almost every week. I promise I'll move on from energy gels soon.

Features & benefits

• Facts per gel: 120 kcal, 30g carb, 0 mg sodium
• 1:0.8 glucose to fructose ratio for very high-carb intakes (over 90g/h)
• Batch-tested

Things to keep in mind

• Gel-like texture but a bit lumpy
• Sweeter than similar gels (Maurten & Precision)

Final take

Choosing this product over others with a very similar composition and texture is a matter of personal preference. Considering this brand is known for their caffeine strips, it's interesting that their energy gels don't have a caffeinated version either. ​​​​​​​​​​​​​​​​​​​​​​​​

👩🏻‍🍳 Kitchen Creations

The ultramarathon sandwich I shared this recipe on my instagram stories recently and I really liked it (at least the concept since I'm yet to try it). It's a great and tasty way of boosting carb-intake, especially during carb-loading. ​Here's a PDF version with the ingredient list & nutrition breakdown based on my calculations. ​Full credit to @pt_with_jt ​

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Happy fuelling!

Gaby | Endurance Nutrition Specialist

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p.s. I personally read and answer your email replies.

PLUS whenever you’re ready, here are 3 ways I can help you optimise your performance:

1. ​Take the FREE Endurance Nutrition Audit. Not sure if your fuelling strategy is working? This quick 3-minute audit will reveal exactly where you stand and what adjustments could help you perform at your best.
2. ​Book a FREE strategy call. Need expert advice on your next best step? Let’s chat! In this commitment-free call, I’ll help you identify key areas to improve and map out a fueling approach tailored to your endurance goals.
3. ​Join the Fuel To Thrive Academy. Ready to take action? My signature program gives you the ultimate fuelling roadmap to unlock your full potential in sport and life, with proven strategies that have helped endurance athletes fuel smarter, perform better and break records.

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