Ironman Distance Triathlon Fueling Guide


Fueling for an Ironman (2.4-mile swim, 112-mile bike, 26.2-mile run) is critical for success. A practiced nutrition plan sustains energy, prevents bonking, and aids recovery. Below are key strategies based on expert and athlete insights.


Pre-Race Fueling

Carb Loading (4-7 Days Out): Gradually increase carbohydrate intake to 8-12g/kg body weight daily to maximize glycogen stores. Focus on complex carbs like rice, pasta, or oats. Example: A 70kg 155lb athlete needs 560-840g carbs/day.
Practice in Training: Test race-day nutrition (gels, bars, chews, drinks) during long training sessions to train your gut and confirm what works. Avoid new foods on race day.
Night Before: Eat a familiar, carb-rich meal (e.g., pasta with lean protein, low-fat sauce). Avoid high-fiber or fatty foods to prevent GI distress.
Race Morning (2-3 Hours Before): Consume 1-2g carbs/kg body weight (e.g., oatmeal, toast, banana, or sports drink for a 70kg athlete: 70-140g carbs). Sip water or an electrolyte drink to stay hydrated.


Race-Day Fueling


General Guidelines


Carbohydrates: Aim for 60-90g carbs/hour (up to 120g/hour for advanced athletes using hydrogel products like Maurten). Use a mix of gels, chews, bars, or sports drinks.
Hydration: Drink 500-750ml/hour, adjusting for sweat rate and weather conditions. Include 500-1000mg sodium/hour via electrolyte drinks or salt tablets. Tools like Precision Fuel & Hydration’s free Fuel & Hydration Planner can personalize this.
Timing: Start fueling early (within 10-15 minutes on the bike) and consume small amounts every 20-30 minutes to maintain steady energy.


By Discipline


Swim (2.4 miles, ~1-2 hours): Fueling is minimal due to logistics. If possible, sip a carb-electrolyte drink 10-15 minutes before the start.

T1
Bike (112 miles, ~5-7 hours): Primary fueling phase. Consume 60-90g carbs/hour (e.g., 2 gels at 25g carbs each + 500ml sports drink at 20g carbs). Sip water or electrolyte drink every 10-15 minutes. Example: 1 gel every 20 minutes + 1 bottle/hour.
special needs bag
T2

Run (26.2 miles, ~3-5 hours): Maintain 30-60g carbs/hour via gels, chews, or drinks, as GI distress is more common. Rely on aid stations or carry a concentrated carb drink. Sip water and electrolytes to replace sweat losses.
special needs bag

Post-Race Recovery


Immediate (0-30 minutes): Consume 1-1.2g carbs/kg body weight + 20-25g protein (e.g., a recovery shake with milk, banana, and protein powder for a 70kg athlete: 70-84g carbs).
Within 2 Hours: Eat a balanced meal with carbs, protein, and moderate fats (e.g., rice, chicken, vegetables).
Hydration: Rehydrate with electrolyte-rich fluids until urine is pale yellow.


Tips from Athletes and Coaches
Alice Alberts (Pro Triathlete): “Fueling is a discipline. Train your gut like you train your swim, bike, and run.”
Emma Yates (Age-Grouper, Ironman Wales): Used a mix of gels and sports drinks, adjusting based on course demands (e.g., hills) and aid station availability.
Rebekah Keat (Coach): Start carb loading 4 days out. Test liquid vs. solid fuels in training to find your preference.


Common Pitfalls to Avoid
Under-Fueling: Leads to bonking (glycogen depletion). Set a timer to eat/drink every 20-30 minutes.
Over-Fueling: Causes GI distress. Stick to practiced amounts and avoid overconsuming at aid stations.
Ignoring Sodium: Low sodium can cause cramps or hyponatremia. Test sweat rate and sodium needs in training (e.g., via sweat tests or Precision Fuel & Hydration).

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Join us on the Endurance Edge Podcast as we dive into expert fueling strategies to conquer your next Half Ironman (70.3) race! In this episode, we break down the science and practical tips for optimizing nutrition before, during, and after the 1.2-mile swim, 56-mile bike, and 13.1-mile run.

What You'll Learn:

• Pre-Race Prep: Discover carb-loading techniques and race-morning meals to maximize glycogen stores without GI distress.
• On-Course Fueling: Learn how to consume 60-90g of carbs per hour on the bike and 30-60g on the run, using gels, chews, and sports drinks tailored to your needs.
• Hydration Hacks: Understand how to balance fluids and electrolytes to avoid dehydration and cramping, with tips on using on-course.
• Recovery Nutrition: Get actionable advice on post-race refueling with carbs and protein to kickstart recovery and prepare for your next challenge.

We share real-world insights, drawing from experiences with top triathletes and age-groupers alike. Whether you're a first-timer or chasing a PR, this episode will help you fine-tune your nutrition plan to cross the finish line strong. Tune in for practical tips, common pitfalls to avoid, and how to test your fueling strategy in training to ensure race-day success.

Listen Now: Available on Apple Podcasts, Spotify, or wherever you get your podcasts. Don’t miss out—subscribe and share to fuel your Half Ironman journey!

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Join us as we dive into the critical role of electrolytes and sodium in endurance sports. From understanding why sodium is king for hydration to comparing popular brands like LMNT, Ultima, BPN Electrolytes, and SaltStick Capsules, this episode is packed with science-backed insights and practical tips for runners, cyclists, and triathletes. Whether you're training for a marathon or an ultra, learn how to optimize your hydration strategy and avoid the dreaded bonk!

Brand Links:
LMNT: https://drinklmnt.com
Ultima: https://ultimareplenisher.com
BPN: https://bareperformancenutrition.com
SaltStick: https://saltstick.com

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