Train Your Gut for Race Day Success

One of the most common reasons runners struggle, or even drop out, during endurance events is gastrointestinal (GI) distress. Nausea, cramping, bloating, or diarrhoea can quickly derail even the best-prepared athlete.

The good news? Your gut is trainable. Just like your muscles adapt to training, your digestive system can learn to better tolerate and absorb nutrition during exercise. Every long run is an opportunity to practise and refine your strategy.

Top Tips to Train Your Gut

1. Experiment with Different Carbohydrate Sources

Not all fuels are created equal. Sports drinks, gels, chews, and real foods contain different types of carbohydrates, which can affect how well they are absorbed and tolerated.

Use your training sessions to:

• Trial different brands and types of fuel
• Notice how your body responds
• Identify what feels comfortable and effective

Once you find what works, stick to it. Race day is not the time to try something new.

2. Build Up Your Carbohydrate Tolerance

Highly concentrated carbohydrate products can sometimes cause gut discomfort, especially if introduced too quickly.

Start by:

• Using lower concentrations of carbohydrate
• Gradually increasing intake over time

Remember: More is not always better. Although you will want to aim for recommended targets, it’s about what your body can tolerate and use effectively.

3. Practise Your Fluid Strategy

Hydration isn’t just about what you drink, but how you drink it.

During training, experiment with:

• Drinking larger volumes less frequently
• Sipping smaller amounts more regularly

You may find that one approach suits you better. Over time, your stomach can also adapt to tolerate larger volumes if trained consistently.

4. Consider Your Evening Meal Before Race Day

What you eat the night before can significantly impact how your gut behaves the next day.

A good general approach is:

• Low fibre, low fat, moderate protein, easy-to-digest carbohydrate-rich foods
• Avoid fatty meals and high-protein meals, which can slow digestion
• Avoid foods that can irritate the gut such as high fibre foods or very spicy options
• Limit alcohol

Good examples include chicken or fish with rice, tomato-based pastas, or eggs on low-fibre toast

If you are particularly prone to GI symptoms, you may benefit from:

• A low FODMAP approach
• Lactose-free options

However, this should be done carefully to avoid unnecessary restriction.

Final Thoughts

Training for races like the Comrades Marathon or Two Oceans Ultra Marathon isn’t just about mileage; it’s about preparing your entire body, including your gut.

A well-trained gut can be the difference between finishing strong and not finishing at all.

If you’re preparing for an upcoming race, now is the time to start practising your nutrition strategy. And if you need support, guidance, or a personalised plan, speak to one of our registered dietitians.

Marie MacGregor (mmacgregor@ssisa.com)

Tayla du Plessis (tduplessis@ssisa.com)