22 Jul Train Your Gut Like You Train Your Legs
Training your stomach to tolerate race day nutrition for an Ironman or 70.3 is just as important as training your swim, bike, and run. GI distress is one of the leading causes of poor race performance. Hopefully the information below will help you succeed in your next race.
Remember the below is guide, not every person responds the same. You can have a different plan to the below, but the key takes are, you have to practice your plan in order for it to work well. We are trying to take the guess work out of race day. We know what we did in training therefore Race Day should be no different.
Key Principle
1. Start Early: Begin gut training 8–10 weeks before race day.
2. Replicate Race Conditions: Use the same intensity, nutrition products, timing, and fluid volumes during your key sessions. The KEY here is the intensity, most people can tolerate carbs at lower efforts. But the most frequent issue is the athlete doesn’t replicate the intensity of racing while trying to consume carbs. So ensure you are doing this at elevated heart rate.
3. Gradual Load: Just like muscles, your gut adapts to stress. Increase volume and frequency of intake over time
The Gut Training Process
1. Know Your Race Nutrition Plan (products you are going to use) aim to consume:
• Carbs: 60–90g/hour (up to 120g/hour if you’re highly trained, but this takes time )
• Fluids: 500–1000 mL/hour (adjust for sweat rate).Sodium: 500–1500 mg/hour depending on your sweat sodium content and sweat rate.
• https://www.precisionhydration.com/sweat-testing/our-sweat-tests/
Above is a link to the a great sweat test service Precision Hydration offers (there is one in Singapore)!! It will measure your sodium loss per litre of sweat. Once you know how much you sweat per hour the rest is simple math.
Example: If you’re using Maurten, Precision Fuel & Hydration, or Gatorade Endurance (common on-course), build your plan around those products.
2. Train Your Gut on Key Sessions (as mentioned earlier, the key to success lies in the specific stressors of race day, so we try out best to simulate that in training)
• Bike long rides (race pace or just below)
• Brick sessions: Add nutrition before and during the run to simulate GI load.
• Race rehearsals (at 70.3 pace): Mimic fueling exactly as you plan on race day.
3. Practice Carb Loading
• Before key training sessions and your race, practice carb loading 1–2 days prior.
• This gives your gut experience with higher-carb intake
4. Build Up Carb Tolerance
• Start with 30–40g/hour of carbs, and increase by ~10g or so each week in long rides.
• Mix sources (gels, drinks, chews, bars) and see what works best for you
• Use glucose + fructose combinations to maximize absorption (e.g., Maurten, SIS Beta Fuel, PF 90 gels)
5. Time and Format
• Take in carbs every 15–20 minutes, not all at once.
• Combine fluid + electrolyte + carb when possible (sports drink), then supplement with gels or solids if needed. Use water to wash down gels or solids.
Advanced Tips
1. Do a “Sweat Test”:
• Weigh yourself before and after a 1–2 hour hard session to estimate sweat loss and hydration needs. Remember to take into account the amount of fluid consumed. So if you lost 1kg in 1 hour,
but you also consumed 1litre of fluids, your true sweat loss is 2 litres per hour. 1 Litre of fluid = 1kg
2. Simulate Pre-Race Meal:
• Test your pre-race breakfast multiple times: 2–3 hours before a key training session.
3. What to Avoid:
• Trying new products on race day. (You can find out what’s on course well in advance these days)
• Overeating or underfueling in training.
• Large fiber/fat/protein intake in the 24 hours before racing.
• Caffeine abuse (test your tolerance in training). We like caffeine, but taking 10 caffeine tablets on race day before trying them is not the best idea. Ha.
