Fuelling for Endurance

My husband is running a half marathon soon, and as his personal nutritional therapist, I am tasked with the job of helping him fuel properly for training and recovery. It’s been fascinating to see how small tweaks — like timing carbs, prioritising protein and staying on top of hydration can make such a difference to his energy, endurance and even mood.

Whether you’re preparing for your first race or simply want to support your body through endurance exercise, getting your nutrition right can make the journey feel smoother, stronger and far more enjoyable.

Key Nutrients

What is Glycogen?

Glycogen is the body’s stored form of carbohydrate, found mainly in your muscles and liver. It’s the primary energy source your body relies on during endurance exercise. When glycogen levels run low, fatigue and slower recovery can set in — often referred to as “hitting the wall.” Regular carbohydrate intake before, during and after training helps maintain glycogen stores and supports consistent energy and performance.

1. Fuel for the Training Phase

The weeks leading up to a half marathon are when your body builds muscle, stamina and resilience.  During this time nutrition should focus on balanced, consistent fuelling, not restriction.

• Eat regularly: Aim for 3 balanced meals plus snacks to support stable energy and recovery.

• Prioritise protein: Protein supports muscle repair and adaption to training (Phillips & Van Loon, 2011).  Include quality protein with every meal (eggs, fish, Greek yoghurt, beans, tofu or a collagen supplement).

• Choose complex carbs: Whole grains, oats, sweet potatoes, quinoa and fruit provide slow-release energy and replenish glycogen stores in the muscles (Thomas et al., 2016).

• Get your healthy fats: Avocado, olive oil, nuts, seeds and oily fish support hormone balance and reduce inflammation (Calder, 2015).

• Mind your micronutrients: Iron, magnesium and B vitamins are crucial for endurance and energy production (Lukaski, 2004).

2. The Day Before the Race

This is not about “carb loading” — it’s about topping up glycogen stores calmly and sensibly.

• Focus on complex carbs with lean protein and veg (think salmon with rice and greens or a veggie stir-fry with tofu and noodles).

• Stay hydrated through the day — aim for water plus an electrolyte drink if you tend to sweat heavily.

• Avoid anything new or overly high in fibre, which can upset your digestion on race day (Costa et al., 2017).

3. Race Morning

Keep things familiar, light and digestible.

• Have breakfast 2–3 hours before your run, leaving enough time for digestion and absorption: something like porridge with berries and nut butter or sourdough toast with eggs and avocado.

• Sip water steadily.

• Consider a small carb snack 30–90 minutes before the start (whole fresh fruits, nuts or homemade energy balls) (Burke et al., 2011).

• Include some nitrate-rich foods such as beetroot, spinach or rocket (arugula) in your pre-race meal or snack. These naturally boost nitric oxide levels, which can help improve blood flow and endurance, and have been shown to reduce time to exhaustion (Gao et al., 2021).

4. During the Race

Once you’re running, hydration and steady carb intake is key.  Beat the bonk (aka hitting the wall) by refuelling regularly:

• Aim to take on 30–60g of carbs per hour after the first 45 minutes — through gels, chews, or a sports drink you’ve tested in training (Jeukendrup, 2014).

• Sip water regularly and use electrolytes to replace minerals lost through sweat (Sawka et al., 2007).

5. Recovery Nutrition

Your post-race meal is your chance to repair, refuel and rehydrate.

• Refuel: Replace glycogen with wholesome carbs like rice, potatoes or oats.

• Rebuild: Aim for 20–30g of protein (fish, eggs, tofu, Greek yoghurt, or a protein smoothie). Research suggests protein ingestion 45-60 minutes post-exercise accelerates muscle recovery and adaptation (Phillips & Van Loon, 2011).

• Rehydrate: Replenish fluids and electrolytes — coconut water is a great natural option.

• Add anti-inflammatory foods to help with muscle soreness: berries, leafy greens, turmeric, and omega-3-rich fish (Calder, 2015).

• Include antioxidant foods (berries, cherries, dark leafy greens and colourful veg) to counterbalance the oxidative stress generated by exercise (Yavari et al. 2015).

6. A Note for Female Runners

Women, especially those in their 40s and beyond, need to pay extra attention to minerals such as iron, zinc and magnesium — all vital for oxygen transport, energy, and recovery (Lukaski, 2004). Hormonal fluctuations (particularly during perimenopause) can affect energy metabolism, fluid balance, and recovery rates (Devries et al., 2020). Fuelling consistently and avoiding under-eating is essential for performance and long-term hormonal health.

Final Thoughts

Training for an endurance event is an incredible goal — one that challenges both body and mind. With the right nutrition, you’ll not only perform better but also recover faster, maintain energy and protect your long-term health.

If you’d like personalised support for your next endurance event — or simply want to optimise your nutrition for energy and performance — I offer one-to-one consultations tailored to your goals.

References

Burke, L. M., Hawley, J. A., Wong, S. H. S., & Jeukendrup, A. E. (2011). Carbohydrates for training and competition. Journal of Sports Sciences, 29(S1), S17–S27.

Calder, P. C. (2015). Marine omega-3 fatty acids and inflammatory processes: Effects, mechanisms and clinical relevance. Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biology of Lipids, 1851(4), 469–484.

Costa, R. J. S., Miall, A., Khoo, A., Rauch, C., Snipe, R., Camões-Costa, V., & Gibson, P. R. (2017). Gut-training: The impact of two weeks of repetitive gut-challenge training on gastrointestinal status, glucose availability, and running performance. Applied Physiology, Nutrition, and Metabolism, 42(5), 547–557.

Devries, M. C., Hamadeh, M. J., Phillips, S. M., & Tarnopolsky, M. A. (2020). Menstrual cycle phase and sex influence on endurance exercise metabolism. Sports Medicine, 50(2), 267–284.

Gao, C., et al. (2021). The effects of dietary nitrate supplementation on endurance performance: A systematic review and meta-analysis. Journal of the International Society of Sports Nutrition, 18(1), 1–13. https://doi.org/10.1186/s12970-021-00450-4

Jeukendrup, A. E. (2014). A step towards personalized sports nutrition: Carbohydrate intake during exercise. Sports Medicine, 44(Suppl 1), S25–S33.

Lukaski, H. C. (2004). Vitamin and mineral status: Effects on physical performance. Nutrition, 20(7–8), 632–644.

Phillips, S. M., & Van Loon, L. J. C. (2011). Dietary protein for athletes: From requirements to optimum adaptation. Journal of Applied Physiology, 110(3), 645–654.

Sawka, M. N., Burke, L. M., Eichner, E. R., Maughan, R. J., Montain, S. J., & Stachenfeld, N. S. (2007). American College of Sports Medicine position stand: Exercise and fluid replacement. Medicine & Science in Sports & Exercise, 39(2), 377–390.

Thomas, D. T., Erdman, K. A., & Burke, L. M. (2016). American College of Sports Medicine joint position statement: Nutrition and athletic performance. Medicine & Science in Sports & Exercise, 48(3), 543–568.

 Yavari, A., Rashidlamir, A., & Mohammadi, F. (2015). Dietary antioxidants and exercise-induced oxidative stress: A review. Journal of Clinical & Diagnostic Research, 9(10), KE01–KE05. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4393546/.