Welcome to the thrilling journey of ultra-runner Jason Williamson, who is set to traverse the length of Ireland from South to North. This incredible feat is not just a test of endurance, but also a noble cause, as Jason is running to raise funds for Temple St Children's Hospital.

Insider Fuelling Tips and Advice

As Jason's trusted nutritionist, I'll be your guide, providing daily updates on his progress and giving you an insider's look into the nutritional strategy that powers this ultra-endurance feat. This is a practical guide on how to fuel an ultra marathon, a topic of interest for many runners and triathletes looking to improve their performance.

Part 1: The Energy Equation Jason's daily target?

An impressive 100 km (60 miles). To sustain this, he requires an energy intake that matches the intensity of his endeavour. We're talking about a staggering 6,700 Kcal for the run itself, plus an additional 1,500 Kcal for his resting metabolic rate. That's a daily total of over 8,000 Kcal - surpassing the energy needs of a Tour de France cyclist, an Ironman Triathlete, or even an Arctic explorer.

In a shorter, single-stage event, managing an energy deficit might not be as critical. But over a 10-day ultra, the goal is to balance energy intake as closely as possible to stave off fatigue and sustain performance. This means our fueling strategy is all about recovery.

Our game plan?

Ensuring Jason replenishes his energy stores every 30 minutes with carbohydrates, maintains a regular meal schedule throughout the day, and employs a targeted carb/protein strategy in the evening. This approach is designed to both conserve and rebuild his glycogen stores.

But how exactly does this work, and why is it so crucial? Stay tuned for more insights as we delve deeper into the science of ultra-endurance nutrition.