Best Energy Bars for an Ultra Marathon

Ultra marathons are not just about gels and drinks. When you are out for 6, 10 or even 24 hours, solid food can become essential. Energy bars offer variety, texture and in some cases a more satisfying way to hit your carbohydrate targets without flavour fatigue.

The key is choosing bars that deliver reliable energy without upsetting your stomach. In an ultra, you want carbohydrates that are easy to digest, practical to carry and simple to portion as the race unfolds.

What Makes a Good Ultra Energy Bar?

During an ultra, your energy demands are high, but so is the risk of gut discomfort. A good energy bar should:

• Deliver meaningful carbohydrate per serving
• Be low in fibre and overly complex ingredients during racing
• Be easy to chew when breathing hard or climbing
• Fit into your hydration and electrolyte strategy

It is also worth thinking about race duration. A 50km event may call for lighter, performance-focused bars, while a 100 miler may justify something more substantial between aid stations.

How to Use Energy Bars in an Ultra

Energy bars work best as part of a mixed fuelling strategy. Many ultra runners rotate between gels, chews, drink mixes and bars to avoid flavour fatigue and reduce the risk of stomach issues.

You might consider:

• Using performance-focused bars in the first half of the race when intensity is higher
• Switching to more substantial options during slower, later stages
• Breaking bars into smaller pieces and eating little and often

Practice is critical. Test your chosen bars in long training runs of four hours or more to see how your stomach responds under fatigue.

If you are unsure how many grams of carbohydrate you should be aiming for per hour, our Nutrition Calculator can help you build a personalised plan based on your bodyweight and race duration.

Here are some great bar options for an ultra:

OTE Duo Bar

The OTE Duo Bar is designed specifically for performance fuelling. Each bar provides 40g of carbohydrate, split into two 20g portions. This makes it easy to measure your intake and avoid overloading your stomach in one go.

One bar offers around 45 to 60 minutes of fuelling support, depending on intensity. It also contains 7g of protein, which can support muscle repair post-exercise and may help reduce muscle breakdown during long events.

RealMeal Bar

When races stretch beyond standard marathon distance, sometimes you need something more substantial. The RealMeal Bar delivers over 600 calories per bar, making it a serious fuelling tool for ultra-distance events, multi-day races or long mountain adventures.

Built around a 60/20/20 macro split, it is designed to provide steady, sustained energy. The plant-based, gluten-free formulation focuses on real ingredients and is trusted by elite military and endurance athletes.

STYRKR BAR50

STYRKR BAR50 sits firmly in the high-performance category. Each bar delivers over 50g of carbohydrates and more than 250 kcal, supporting sustained energy output during long sessions and races.

The blend of fast and sustained-release carbohydrates helps provide immediate fuel while supporting longer-lasting energy availability. It also includes electrolytes, which can aid hydration during extended efforts and complement your drink strategy.

FAQs

Are energy bars better than gels for ultra marathons?

Not necessarily better, but often complementary. Bars provide texture and variety, which can help over long durations when gels become repetitive.

When should I eat a bar during an ultra?

Bars are often best used during steadier sections of the race where you can chew comfortably and manage intake without spiking intensity.

Can I rely only on bars for an ultra?

It is possible, but most runners benefit from combining bars with gels or drink mixes to make it easier to hit higher carbohydrate targets consistently.

Summary

Energy bars can play a vital role in ultra marathon fuelling. They provide variety, structure and in some cases higher calorie options that help you sustain performance over extreme distances.

From portion-controlled performance bars to high-calorie real food options and high-carb race-focused designs, the right choice depends on your race length, intensity and gut tolerance.