Ultramarathon Nutrition Course: How to Fuel an Ultra

Rebecca
Oct 13
2 min read

Updated: 4 days ago

It was running ultramarathons that first got me interested in sports nutrition. You can wing it for a marathon — your performance will suffer, but you can still finish. The same is not true for an ultramarathon, where fuelling and hydration become essential parts of success.

Being able to eat and drink for hours on end is as important as time on feet or packing your race vest efficiently. It’s a skill that can make or break your race.

Ultrarunners gather at the UTMB race start for the OCC in a narrow street. Colorful gear and race vests fill the scene, with a misty mountain backdrop. — Ultrarunners at the start line of the UTMB OCC race

The Marathon v Ultramarathon: Why Nutrition Matters More

Ultramarathons expose every weakness in your fuelling plan. And it’s not as simple as scaling up your marathon strategy.

Slower paces, taste fatigue, and gut issues mean you need to test, adapt, and train your gut well before race day.

My first ultra — a 50km Action Asia event in Hong Kong — taught me that lesson the hard way. Hot, humid, and with 1,500m+ of elevation, I went from “prepared” to struggling to eat by 30km. Without those fresh oranges at the aid station, I might not have finished. That experience showed me how critical nutrition is — and set me on the path to becoming a Registered Sports Nutritionist.

Runner holding a large trophy cutout with "50km" text, standing on a red carpet at the finish. Background shows cityscape and MSIG HK50 branding. — At the finish of the MSIG HK50 race in Hong Kong

Common Ultra Nutrition Mistakes

After working with endurance athletes and racing myself, I’ve seen the same mistakes over and over:

🚫 Not eating early enough in the race

🚫 Relying too heavily on sports gels and ignoring real food

🚫 Forgetting about hydration and electrolytes until it’s too late

🚫 Not practising nutrition during training

Ultramarathons are as much about energy management as they are about endurance.

Respect Nutrition as Much as You Respect Mileage

You wouldn’t skip your long run — so don’t skip your nutrition planning either. What you eat and drink is what powers every mile, every climb, and every finish line.

That’s why I created the Ultramarathon Nutrition Course — a five-part online series designed to help ultra runners fuel smarter, recover faster, and Perform Better.

What you'll Learn

How to fuel training days, back-to-back runs, and long races
Gut training strategies to avoid GI issues
How to design your race-day plans for 50K–100 mile events
Practical, real-world advice from a sports nutritionist and ultrarunner

Whether you’re training for one of the UTMB races, Lakeland 100, Centurion races, a Backyard Ultra or another ultramarathon, this course will give you the tools and confidence to create a personalised ultramarathon fuelling plan.