Five days out from Ironman Japan now, so let's talk fuelling - the full race day plan.
The numbers: 90 to 120 grams of carbs an hour, and 750ml to a litre of fluid depending on the heat, with roughly 1000mg of sodium in there too. These aren't guesses - they're numbers I've actually tested, in training and in my last few races.
| Phase | Nutrition/hour | Carbs/hour | Electrolytes/hour | Fluid/hour |
|---|---|---|---|---|
| Pre-Swim | Breakfast, caffeine gel | - | - | - |
| Bike | 4 x gels/chews | 90-120g | 1000mg sodium | 750-1000ml (heat-dependent) |
| Run | 2 x gels/chews | 30-60g | 500ml electrolyte flask | As needed, topped up at aid stations |
Swim: no fuelling, obviously. But a strong coffee with breakfast, and a caffeine gel about 30 minutes before the start.
Bike is where most of it goes in - four gels or chews an hour, caffeinated ones spaced out through the course. I'll top up fluid based on the heat, but I'm not skimping just because it doesn't feel that warm, because I'll still need it later.
Off the bike, I'll head out of T2 with a soft flask of electrolytes and ease into it. Most of the real nutrition's already in from the bike, so the run is lighter - 30-gram gels every 30 to 40 minutes.
Toward the end, once stomach fatigue kicks in, I'll probably just be grabbing whatever's at the aid stations. I can honestly never predict what I'll actually want 35km into an Ironman marathon.
I've practiced this exact plan enough times now that race day shouldn't be the first time trying any of it.
