1. Why this matters
Many athletes struggle to fuel enough—not because they lack knowledge, but because their gut can’t always tolerate what they’re trying to consume during exercise.
GI symptoms such as nausea, cramps, bloating, and diarrhoea are common in sport.
Research shows:
• 30–50% of athletes experience GI symptoms during exercise
• In endurance runners, prevalence can reach 30–90%
• Around 7% of triathletes report GI issues as the sole reason for race withdrawal
These symptoms can reduce intake, impair performance, and in some cases end a race entirely.
Over time, athletes often respond by eating less—leading to low energy availability (LEA) and increased risk of RED-S.
The goal isn’t to eat less.
It’s to fuel in a way your gut can tolerate while meeting energy needs.
2. Why GI symptoms happen
During exercise, three main mechanisms contribute:
❤️ Physiological
Blood flow to the gut can decrease by up to ~80% during intense exercise, reducing digestion and absorption.
🏃 Mechanical
Impact (especially running) and posture (cycling) can physically stress the GI tract.
🥤 Nutritional
Food type, timing, and concentration directly affect gut tolerance.
3. Common triggers
Athletes are more likely to experience GI distress with:
❌ High-fibre meals pre-exercise
❌ High-fat foods before training
❌ Large protein-heavy meals close to exercise
❌ Very concentrated carbohydrate drinks or gels
❌ Dehydration
4. Before exercise: gut-friendly fuelling strategies
GI symptoms are not just about what happens during exercise—they often start before you even begin.
This is especially important for athletes with:
• IBS or sensitive guts
• Race-day anxiety
• High training stress
✔ Choose gut-friendly carbohydrate sources
Focus on simple, low-residue carbohydrates such as:
• Cassava-based carbohydrates
• Plantain-based foods
• Fufu-style starches
• Other easily digestible low-fibre carbs
These are often better tolerated because they are:
• Lower in fibre
• Less bulky in the gut
• Easier to digest pre-exercise
(Compared with higher-fibre options like oats, which some athletes find harder to tolerate before training.)
✔ Reduce gut stress pre-exercise
• Reduce fibre 2–6 hours before exercise
• Avoid high-fat meals
• Keep meals familiar and simple
✔ Manage nervous system stress
The gut is highly sensitive to stress.
For athletes with:
• Race anxiety
• IBS symptoms
• High training load
GI symptoms can increase even when nutrition is optimal.
Key strategies:
• Stick to familiar foods
• Avoid experimenting on race day
• Keep routines consistent
✔ Hydration
• Start well hydrated
• Avoid dehydration and over-drinking
• Sip fluids rather than large volumes at once
5. The biggest mistake
When GI symptoms appear, many athletes respond by:
• Eating less
• Avoiding carbohydrates
• Skipping fuelling during training
This may reduce symptoms short-term…
But often leads to chronic under-fuelling.
6. The hidden risk
Repeated under-fuelling can contribute to:
⚠️ Low Energy Availability (LEA)
⚠️ Poor recovery
⚠️ Reduced training adaptation
⚠️ Hormonal disruption
⚠️ Increased injury risk
⚠️ RED-S
7. Why RED-SCUE is gut-friendly
At RED-SCUE, we design fuelling strategies around real-world gut tolerance and consistency.
We focus on:
• Simple, easy-to-digest carbohydrate sources
• Real-food-based fuelling options
• Low-complexity nutrition strategies
• Structured fuelling plans (not guesswork)
• Supporting intake before, during, and after exercise
This includes carbohydrate bases such as cassava and plantain, chosen because many athletes report better tolerance in practice compared with more fibrous or heavy options.
The goal is simple:
fuel that works with your gut, not against it.
8. Why we created RED-SCUE energy bars
Many athletes don’t fail due to lack of discipline.
They struggle because fuelling is not always gut-friendly or easy to execute consistently.
That’s why we created RED-SCUE energy bars:
To support structured fuelling strategies with a simple, portable, gut-friendly carbohydrate option for:
• Before training
• During longer sessions
• After exercise
Made using real-food carbohydrate foundations like cassava and plantain-based ingredients, to support tolerance and consistency.
Because when fuelling is easy on the gut…
you’re far more likely to actually do it.
9. Real athlete experience
Not all carbohydrates sit the same with every athlete.
I used to struggle with gut issues when fuelling with oats before training.
When I switched to cassava-based carbohydrates, I found them much easier to tolerate—and my training became more consistent as a result.
This highlights an important point:
gut tolerance is highly individual and must be tested in practice.
10. Take-home message
GI symptoms are common—but manageable.
The solution isn’t eating less.
It’s building a structured, gut-friendly fuelling strategy that allows athletes to:
• Meet energy demands
• Improve performance
• Reduce GI distress
• Lower risk of LEA and RED-S
Reference
Oliveira EP, Burini RC, Jeukendrup AE.
Gastrointestinal Complaints During Exercise: Prevalence, Etiology, and Nutritional Recommendations.
Sports Medicine, 2014.
