The No-BS Guide to Ultra Nutrition

By  Tom McClure 

So you’ve signed up for an Ultramarathon.

Here’s the part nobody warns you about enough: nutrition is going to make or break your race just as much as your legs will.

You can be the fittest athlete on the start line and still end up walking, nauseous, and broken by mile 40 because you got your fuelling wrong.

Start With the Big Rocks, Not the Hacks

There’s more noise around endurance nutrition than ever. More brands, more products, more people online selling you the next “one percenter.” Our take? That’s actually made things harder, not easier. Forget the hacks. Get the big rocks in the jar first.

That means: eat enough day to day, eat enough around your sessions, and only then start thinking about what you’ll use on your long runs and eventually on race day. Same principle as your training – you build a base before you get fancy.

A simple way to start: go and buy individual servings of a few different fuelling brands.

Find a gel that sits well, a chew you actually enjoy, something a bit more solid like a flapjack, and a liquid carb option. Give yourself three or four weeks to figure out what you can tolerate.

Why Your Gel Choice Actually Matters

Here’s the bit most athletes get wrong: your body can only absorb around 60g of carbohydrate per hour from glucose alone. Grab a standard glucose-only gel and try to smash three or four an hour to hit higher targets, and you’ll pay for it – badly.

The fix is simple. Look for products that combine glucose and fructose. That opens up a second pathway for your body to absorb carbohydrate, meaning you can push closer to 90g an hour without your gut staging a revolt. This is why we work with brands like Precision Fuel & Hydration – their products are built around this exact science, and the serving sizes (30g, 60g, 90g) make the maths dead simple mid-race.

Rule of thumb:

• Minimum: 60g of carbohydrate per hour
• Target for most ultra athletes: 90g of carbohydrate per hour

Practice Your Fuelling Like You Practice Your Training

You wouldn’t turn up to race day having never run the distance. Don’t turn up having never tested your fuelling either.

In the 6–8 weeks before your race, start training your gut the same way you train your legs – gradually pushing from 60g toward 80-90g of carbohydrate per hour on your longer sessions. Use your two or three big training weekends to fully replicate what you’ll do on race day: same products, same timing, same kit.

Carb Loading: Forget the Three-Day Myth

If you want to explore how this applies to your own training – whether that’s building a running and cycling balance, getting support with fuelling, or working with a coach directly – get in touch with the OMNIA team.

Find out more about Omnia 1:1 Coaching here.

Or, if you’d like an introduction to hybrid training – you can download our free hybrid training guide here.