Triathlon Nutrition Calculator — Sprint to Ironman Fueling Plan
Get your complete triathlon nutrition plan for Sprint, Olympic, 70.3, or 140.6 distances — including gels per segment, fluid targets, and transition nutrition strategy.
No food. Focus on even effort and sighting. Hydrate in T1.
80g carbs/hr. First gel at 15 min mark. Every 30-35 min after.
60g carbs/hr. Gels only — no solid food. Every 35–40 min.
T1 Note
Drink a full bottle in T1. Grab extra gel for first 15 min on bike.
T2 Note
Take a gel immediately in T2 if run > 45 min. Drink to thirst from first aid station.
16 gels across swim, bike & run
NorthLine Gold Gels — 22g dual-source carbs, easy on the gut
Why Triathlon Nutrition Is Different
In a single-discipline race, nutrition is linear. In triathlon, each segment has fundamentally different nutrition rules — shaped by GI stress, body position, and what your gut can handle at race intensity.
Nutrition by Discipline
Swim: No nutrition is taken during the swim in any triathlon format. The horizontal body position, effort level, and inability to eat make it impractical. Focus on starting well-hydrated and grab your first fluid in T1.
Bike: This is your primary fueling window. The relatively relaxed body position, lower GI stress, and longer duration make the bike the best segment to load carbohydrates. For 70.3 and Ironman, targeting 80–90g/hr on the bike is achievable and necessary.
Run: GI sensitivity increases sharply on the run. The vertical impact, accumulated fatigue, and heat load combine to make solid food nearly impossible for most athletes. Gels every 30–40 minutes and water at every aid station is the standard protocol.
Transition Nutrition
T1 (Swim → Bike): Drink immediately — even 200ml in transition helps. Take a gel in the first 15 minutes of the bike before settling into effort.
T2 (Bike → Run): Take a gel immediately in T2 if your run is longer than 45 minutes. This bridges the nutrition gap between the last bike gel and when you can next fuel on the run.
The Ironman Rule: Never Let Glycogen Fall Below 30%
In a 140.6, the combined duration means you cannot afford even a 20-minute fuelling gap. Set a timer or use course landmarks — not hunger — to trigger gel intake. By the time you feel hungry, glycogen is already critically low.
Q: Can I eat solid food on the Ironman bike? A: Yes, and many athletes do — rice balls, banana pieces, and energy bars are common for the first 2–3 hours. Transition to gels in the final 60–90 minutes of the bike to prime your gut for the run.
Q: How much should I drink on the bike? A: 500–750ml per hour in cool conditions, 700–1,000ml/hr in heat. Always include electrolytes — sodium especially. Hyponatremia is a real risk in long-course triathlon.
Frequently Asked Questions
Q: How many gels do I need for a 70.3?
A: A 70.3 athlete typically needs 4–6 gels: 3–4 on the bike and 2–3 on the run. The exact number depends on your finish time and whether you supplement with other carbohydrate sources (sports drink, banana) on the bike.
Q: Should I practise nutrition in training?
A: Absolutely — the gut is trainable. Practice your exact race-day nutrition strategy in your longest brick sessions. Take the same gels at the same intervals. Your GI system needs conditioning to handle high-carb intake at race intensity.
Q: What is the biggest nutrition mistake in triathlon?
A: Under-fuelling on the bike. Many athletes are conservative on the bike to "protect" their run, then hit the run depleted. The run suffers far more from poor bike nutrition than from appropriate bike fuelling. The bike is your fueling window — use it.
Verified Data Sources & Authority References
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