Rule 28 · Performance Lab
Nutrition Calculator.
Carbohydrate, fluid and sodium targets built from your actual effort — not a fixed number everyone gets. Based on current sports-nutrition research, including the shift toward multiple-transportable carbohydrates and drinking to thirst rather than a fixed schedule.
01Your effort
Duration and power drive most of this. Intensity tells us how hard relative to your own limit — that changes which fuel you burn.
Drives your heat production, and so your fluid need — independent of how hard that feels.
Relative to your own limit. Drives how much of that effort is fuelled by carbohydrate.
Leave these blank and we'll use science-based defaults. If you've tested your own sweat sodium (via a sweat test) or know your practised carb ceiling from training, add it here for a tighter number.
02Your fuelling targets
Ranges, not single numbers — real effort and conditions vary, and so should your plan.
03Before the start
Fuelling a long effort starts the day before, not on the start line.
04On the bike
A rough timeline so you're not deciding what to eat while you're already behind on it.