Ironman Fueling Planner Pro
Build a weather-adjusted, hour-by-hour Ironman nutrition plan with real-time coaching feedback. More advanced than any free calculator — and exportable to PDF.
Step 1 — Pick your race
Weather conditions automatically adjust fluid, sodium and carb recommendations.
Weather engine
💡 Brutal heat + humidity + lava field radiation. Plan +20% fluids and sodium.
How to train your fueling strategy
Long ride simulation
Once every 3 weeks, ride 4–6 hours hitting your exact race-day carb and fluid targets. Use the same products you'll race with.
Gut training
Train your gut like a muscle. Start at 60g carbs/hour and add 10g every 2 weeks until you reach your target. Most athletes need 8–12 weeks.
Brick session fueling
Practice the bike-to-run transition fueling: take your last bike gel 20 min before T2, then a small sip of cola at mile 1 of the run.
Caffeine periodization
Reduce caffeine intake the week before the race. Lower tolerance = bigger race-day boost from your planned dose.
Frequently asked questions
How many carbs per hour during an Ironman?
Most trained athletes target 80–100g carbs/hour on the bike and 60–80g/hour on the run. Elite athletes with gut-trained stomachs push 110–120g/hr on the bike. Beginners should start at 60g/hr to avoid GI distress.
How much sodium do I need during an Ironman?
Plan 600–1000mg sodium per hour as a baseline. Heavy sweaters, hot races (Kona, Cozumel, Malaysia) and athletes with cramping history need 1000–1500mg/hr. Use a sweat test for an exact number.
How do I fuel the Ironman bike leg?
The bike is your refueling window: aim for 80–110g carbs/hr from gels, drink mix and chews. Drink 500–800ml/hr depending on heat (a 750ml bottle covers most of an hour). Eat solid food only in the first 60–90 minutes — switch to liquid carbs as race intensity rises.
What should I eat during the Ironman run?
Switch to easy-to-digest carbs: gels, flat cola, broth, and small amounts of fruit. Take in 60–80g carbs/hr — your gut tolerance drops on the run due to reduced blood flow. Aid stations serve 150ml cups; aim for 2–4 cups per hour.
When should I take caffeine in an Ironman?
Save caffeine for the second half of the race (after hour 5–6 in a 12-hour race). Aim for 100–200mg/hr from caffeinated gels or flat cola. Front-loading caffeine causes a crash later.
Can this planner replace a sports dietitian?
No. This tool gives science-based starting points. For elite-level execution or if you have medical conditions (diabetes, IBS, hypertension), work with a sports dietitian who can analyse blood, sweat, and gut tolerance.
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