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Chargement…
Chargement…
Ironman is won as much at the table as in training. Bad nutrition = guaranteed bonk on the run. Here's the complete strategy from prep phase.
An Ironman = 8,000 to 12,000 kcal burned. You can't ingest that much during — stomach absorbs only ~250-400 kcal/h. So you finish in deficit. The question isn't 'how to compensate everything' but 'how to limit deficit to avoid collapse'. Target: 60-90g carbs per hour of effort, ~240-360 kcal/h over 9-15h.
Concretely, stomach and intestine decide. A runner not trained to eat 60-90g/h ends up at 30g/h on race day because beyond they vomit. Result: massive energy deficit, glycogen empty at km 25 of marathon, walk, tears, finish at 14h instead of 11h. Classic 1st Ironman mistake.
Domains to master to not blow up on race day.
+ 60-90g carbs/hour. Mix glucose + fructose (2:1 ratio) for maximum absorption. Sources: gels (25g each), well-dosed iso (40-50g/h), gummies, energy bars on bike.
− Under 40g/h you blow up on run. Over 100g/h you trigger GI issues. Useful range is narrow and personal.
+ 500-800ml water per hour depending on heat. Sodium: 500-1000mg/h (lost in sweat). Without enough sodium: cramps, hyponatremia, collapsed performance. Salt tabs or well-dosed iso.
− Drinking too much plain water without sodium = hyponatremia (real Ironman hospitalisation cases). Under-drinking = dehydration and collapsed performance.
+ Classic carb loading: increase carbs to 7-10g/kg/day in 3 days before. Race day breakfast: 600-800 kcal, 3-4h before start. No new foods in the week.
− Badly-executed carb loading (too early, too late, excess fibre) = heaviness, gut issues on race day.
+ You must train eating 60-90g/h on long bike rides from base phase. Stomach trains over 6 months. NEVER introduce a new product in last 4 weeks before race.
− Ironman prepped without nutrition training = 80% bonk. Most neglected and most rewarding programme session.
1 iso bottle (40-50g carbs) per hour + 1 gel every 30-45 min + 1 energy bar every 2h + 2 salt tabs/h in heat. Target: 80-90g carbs/h. Bike accounts for 70% of race nutrition.
Take 1 gel + drink 1 large cup of water + 1 salt tab. You're switching from organised bike nutrition to course aid stations (cups + organiser gels).
Aid stations every 1-1.5 km: alternate water, iso, gel, coke from km 20 (fast sugar + caffeine). Sip per station, no big gulps. Target: 50-60g carbs/h on run (stomach more fragile than on bike).
Nutritional recovery = 1g protein/kg + 1g carbs/kg in first hour. Avoid alcohol 24h (liver recovery). Sleep is key.
Testing new gel or drink on race day = Russian roulette. Everything must have been used on at least 4-5 long sessions.
Eating too much in last 2h before start = bloating + nausea during swim. Stop solids at H-3, sip iso to H-30min.
Forgetting sodium in heat = cramps + hyponatremia. Salt tabs (200-300mg/h extra) are vital above 25°C.
Drinking too much plain water (no sodium) = blood dilution, hyponatremia symptoms nausea/confusion. Iso drink MUST contain sodium.
Counting on race aid stations for everything: not enough. Carry 4-6 extra gels + caffeine for last 20km of marathon.
Ironman training
The format where nutrition makes the difference.
Half Ironman training
Format where nutrition already matters.
The long bike ride
The place to test race nutrition.
Triathlon training — Overview
The 5 formats explained.
Pick your race and train for it
The race calendar: training partners, nearby routes and carpooling for every event
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