💡 Fuel For Thought

Your rest day hunger is trying to tell you something

Have you ever finished a big training week, reached your rest day, and suddenly felt like you could eat everything in sight? It feels backwards. You move less, yet somehow you eat more, graze longer, and still feel unsatisfied.

Rest-day hunger often isn’t about what you did today. It’s your body responding to what you’ve asked of it all week.

Hard exercise can temporarily dampen appetite. While you’re training, hunger signals may become quieter as blood flow, stress hormones, and your nervous system prioritise performance over eating. But reduced hunger doesn’t mean lower fuel needs. It simply means the message may arrive later.

Then your rest day comes around. Training stress drops, appetite suppression eases, and your body finally has space to speak up. Sometimes loudly.

There may also be an energy debt in the background. If you consistently underfuel training days, your body keeps track. Eventually, it asks you to catch up through stronger hunger, cravings, and persistent thoughts about food.

You may think it's poor willpower. In fact, it's a biological response to unmet energy needs.

Rest days still require fuel for muscle repair, glycogen replenishment, and hormonal and immune recovery. You may need slightly less than on a long training day, but usually not as little as you think.

So instead of fighting rest-day hunger, get curious about it. Are your training-day meals substantial enough? Are you recovering soon after sessions? Are you treating rest as part of training, or as a reason to restrict?

🚀 Endurance Highlights

1️⃣ Why underfuelling doesn't always show on the scale

Many athletes assume that if the number on the scale is holding steady, they must be eating enough. But energy availability and energy balance are not the same thing, and confusing the two is one of the most common reasons underfuelling goes unnoticed. This recent narrative review examined how chronic low energy availability reshapes an athlete's body composition and physiology. ​

When energy is scarce, resting metabolic rate falls, thyroid and other anabolic signals drop, and the body becomes more fuel-efficient. This can happen even when body mass stays stable, and there's no obvious calorie deficit, because the body defends its weight by slowing down. The review found the evidence strongest for bone and muscle: sustained low energy availability reliably lowers bone mineral density and suppresses muscle protein synthesis, with measurable losses in lean mass even when athletes train hard and eat adequate protein.

That slowdown is exactly what makes underfuelling so easy to miss. An athlete can feel like they're eating plenty while still shortchanging the systems that keep bone, muscle, and hormones healthy. Stable weight, and even a sense of "gaining fat," can coexist with genuine underfuelling. This is why energy availability, not the scale, is the more meaningful marker for endurance athletes, whose high training volumes make unintentional low energy availability especially common.

2️⃣ Ketones, caffeine and performance in the heat

Ketone supplementation has been gaining attention in recent years, but evidence that it improves endurance performance remains mixed. This new study tested whether ketone monoesters could be particularly useful when athletes are under significant physical and mental strain. ​

With ketones, participants performed better on some measures of attention and working memory and lasted an average of 1.9 minutes longer in the final test. However, the response varied considerably: just over half showed meaningful improvement, while others experienced no benefit or performed worse. Ketones also did not improve every cognitive test or reduce heart rate or core temperature, suggesting they did not make the heat feel physiologically easier.

So, this is an interesting result, but not yet a reason to rush out and buy ketones. The study was small, included only young, well-trained men, and tested ketones alongside a substantial caffeine dose under an unusually demanding military-style protocol. We therefore cannot separate the effects of ketones from their interaction with caffeine or assume the findings will translate to conventional endurance racing.

🕵🏻‍♀️ Retail Finds*

This week's product review: Allen's Speckled Snakes

Thank you to Phil Gore for bringing this product to my attention.

Features & beenfits

• Facts per serving (25g / 2 snakes): 67 kcal, 15.6 g carb, 0 g protein, 0 g fat and 15 mg sodium
• Sweet and citric flavour blend
• Budget-friendly

Things to keep in mind

• Not gluten-free

Final take

These snakes are very similar to Nerd's clusters. Even though Nerd's clusters are slightly more carb-dense, I found it convenient that 2 Speckled Snakes are equivalent to 13 Nerd's Clusters. ​​​​​​​​​​​​

👩🏻‍🍳 Kitchen Creations

​Download the recipe​​​

Chicken Caesar Skewers with Zucchini I like how easily skewers can transform a protein into a delicious blend of flavour and colour. Serve this with your preferred bread or other carb to make it a complete, balanced meal.

I'm committed to sending the most valuable endurance nutrition newsletter. I want to make sure that every piece of content you receive includes information that helps you on your journey toward achieving your personal best.

Happy fuelling!

Gaby | Endurance Nutrition Specialist

🏃🏻‍♂️ Want to work together?

When you’re ready, here are 3 ways I can help you:

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.