Gut Training for Endurance: How Nut Butter Stacks Up Against Carbohydrate Gels

Exciting News for Endurance Athletes!

Endurance sports aren’t just about fitness—they test your gut too. Many athletes struggle with bloating, nausea, or stomach discomfort during long efforts, and the right fuelling choices can significantly impact performance.

A newly released study on gut training and endurance fueling featured Roam Energy Nut Butter, and the results are great news for those looking for a real-food alternative to traditional gels. The research confirms that Energy Nut Butter can help train your gut to adapt to consuming fuel during exercise—making it a practical choice for endurance athletes.

We weren’t surprised, but it’s always rewarding when science backs up what we’ve known all along. Roam co-founder, Andrius Ramonas, holds a PhD in Exercise Physiology focusing on nutrition, so we take this stuff seriously. In fact, one of our core brand values is Sensible Science. That’s why we were thrilled when Roam Energy Nut Butter was included in this independent study.

This is article examines the study, including insights into gut training, endurance performance, and nutrition strategies. 

 

What Was the Study Trying to Discover?

This research aimed to answer some key questions about gut training and endurance fueling:

• Can gut training with a high-fat supplement (i.e. Energy Nut Butter) improve digestion and tolerance compared to a high-carb supplement (that is, a gel)?
• Does fat vs. carb consumption during training impact energy availability, metabolism, and gastrointestinal distress when consuming a high-carb load during exercise?
• Can gut training with different macronutrient compositions (fat vs carbs) improve endurance performance?

What is Gut Training (and Why Does It Matter)?

“Gut training” is the process of gradually conditioning your digestive system to handle food and fluids during exercise. By consistently exposing your gut to different types and amounts of fuel, you can:

✅ Improve digestion & nutrient absorption
✅ Reduce stomach discomfort (bloating, nausea, cramps)
✅ Enhance endurance performance

This study examined whether the type of fuel—fat-based or carbohydrate-based—matters when training your gut. You’ve probably heard the saying, “train with what you’ll eat on race day.” This research tested that theory to see if it truly impacts gut adaptation and fueling efficiency.

How Did the Study Test Gut Training?

The Study Design:

• 44 endurance-trained recreational athletes participated
• Initial Gut Challenge (Pre-Test): Athletes completed a 2-hour steady-state run at 60% V̇O2max while consuming a low-fructose, high-carb gel every 20 minutes (87 g/hr). They then completed a 1-hour self-paced distance test.
• 7-Day Gut-Training Intervention: Athletes were split into two groups for gut training during a 1-hour daily session at 60% V̇O2max:
  • Fat-Fueled Group: Consumed 60g/hour of Roam Energy Nut Butter (3 x 20g doses: 124 kCal, 11g fat, 3g protein, 3g carbs per dose)
  • Carb-Fueled Group: Consumed 141g/hour of a chocolate-flavoured carbohydrate gel (3 x 47g doses: 123kCal, 29g carbs per dose)
• Post-Challenge Testing: Both groups repeated the 2-hour steady-state run and 1-hour self-paced distance test. Researchers measured:
  • Gastrointestinal symptoms
  • Blood glucose levels
  • Total distance covered

Key Findings: How Did Roam Energy Nut Butter Perform?

1. Gastrointestinal Symptoms

✅ Both groups experienced fewer total and upper GI symptoms after gut training.
✅ The Nut Butter group saw a notable reduction in lower GI symptoms, which could be beneficial for athletes who struggle with stomach distress from high-carb gels.

2. Performance Gains

✅ Both groups improved their performance in the post-challenge trial.
✅ The Nut Butter group covered more distance, although this result was not statistically significant.

3. Metabolic Factors & Digestion

✅ No major differences were found in digestion speed (orocecal transit time) or fuel tolerance between groups.
✅ Interestingly, the peak breath hydrogen levels - which indicate how much undigested carbohydrate reaches the gut and gets fermented by bacteria - were lower in the Nut Butter group. This suggests that those who trained with nut butter may have had better digestion and absorption of their fuel.

What Does This Mean for You?

✅ Gut-Training Works

Training your gut can reduce stomach issues and improve fuel tolerance, whether you’re using a high-fat or high-carb supplement.

✅ Fuel Adaptation > Macronutrient Type

The biggest takeaway? Adapting your gut to handle fuel matters more than whether you’re consuming fat or carbs. So if gels aren’t your thing, you’ve got real-food alternatives like Energy Nut Butter!

✅ Personalised Fuelling is Key

The best fuelling strategy is the one that works for you—based on your gut tolerance, preferences, and training goals.

Roam Energy Nut Butter for Endurance Exercise

The study confirms that Roam Energy Nut Butter is a practical, effective, and gut-friendly alternative to high-carb gels - especially for training. It fuels endurance athletes without the sugar spike and is perfect for those who prefer real food over gels.

So if you’re looking for a natural, gut-friendly fuel that performs just as well for lower-intensity training runs, give Energy Nut Butter a go. Your next adventure might just thank you for it!

References

The study referred to in this article is: 

Martinez, Isabel G., Jessica R. Biesiekierski, Christopher E. Rauch, and Ricardo J.S. Costa. "Repetitive Feeding-Challenge With Different Nutritional Densities on Markers of Gastrointestinal Function, Substrate Oxidation, and Endurance Exercise Performance". International Journal of Sport Nutrition and Exercise Metabolism (published online ahead of print 2025). <https://doi.org/10.1123/ijsnem.2024-0145>