Train Your Gut

Why Training Your Tummy Matters

One of the biggest causes of DNFs (Did Not Finish) in marathons isn’t blisters or fatigue, nope, it’s stomach trouble. That’s right, nausea, cramps, diarrhoea, and bloating can derail even the best-trained athlete.

The good news? Just like your muscles, your tummy can be trained to handle the fuelling demands of 26.2 miles.

How Much Fuel Do You Really Need?

During a marathon your body burns carbs at a high rate. To avoid the dreaded wall, you need to replace them as you go.

Guidelines:

• Carbs during training/racing: 30–60g per hour for most runners.

• Well-trained gut (experienced runners): up to 90g per hour (split between glucose + fructose sources).

💡 Per kg body weight:

• Daily carbs (training load): 5–7 g/kg body weight (moderate) up to 10–12 g/kg (heavy loads, race week).

• Daily protein: 1.2–1.6 g/kg body weight for regular runners; up to 2 g/kg during heavy training or injury rehab.

Example: A 65kg runner in peak marathon training may need 325–455g carbs/day and ~100g protein/day.

Why GI Issues Happen

• Too much fuel too soon (flooding the stomach).

• Using products you’ve never trained with.

• Running intensity too high (reduced blood flow to the gut).

• High-fibre/fat meals before long runs.

How to Train Your Gut

1. Start Early

   • Begin practising fuelling 10–12 weeks before race day.

   • Use long runs as “dress rehearsals.”

2. Start Small

   • If you can’t tolerate a full gel, try half a gel every 20 minutes.

   • Gradually increase volume.

3. Consistency

   • Practise the same strategy weekly.

   • Stick to the same gels/drinks you’ll use on race day.

4. Practise Breakfast Too

   • Eat the same pre-run meal you’ll use on race morning (toast, bagel, porridge).

   • Train your stomach to handle food + running.

5. Mix Carbs for Efficiency

   • Products with glucose + fructose blends allow higher carb uptake (closer to 90g/hour).

   • Read labels because not all gels are the same.

Hydration and Electrolytes

GI issues can be worsened by dehydration. Pair your fuelling with regular fluid intake:

• 150–200ml every 20 minutes.

• Use sports drinks where possible to combine carbs + electrolytes.

Conclusion

Gut training is as important as leg training. Practise fuelling early, build tolerance gradually, and know your numbers:

• Daily carbs: 5–10 g/kg depending on training load.

• Daily protein: 1.2–2 g/kg for recovery and resilience.

• On the run: 30–60g carbs/hour (up to 90g for trained guts).