A fueling plan that changes when the forecast does
Tired of building a fueling plan in February and running a race that turns out twenty degrees warmer than the day you planned for?
From ten days out, CarbRate reads your race-day forecast and shows you exactly what a warmer or cooler morning does to your sweat rate, your fluid, your sodium and your finish time.
One tap updates the plan. Nothing changes behind your back.
Why a warm race wrecks the fueling plan you built perfectly for a cool one
You build the plan weeks out, off a typical temperature for that date and a humidity number you half guessed.
Then race morning is 72°F and sticky.
Warm, humid air raises what you sweat, and it raises it a long way. Sweat losses are driven first by how hard you are working and the conditions you are in.
More sweat means more fluid, and more fluid changes the concentration of sodium that fluid needs to carry.
Heat also slows you down, and a slower race is a longer race, so the total amount of fuel you need goes up even though the rate per hour does not.
Every one of those numbers moved, and the bottle you mixed the night before did not.
Most runners find that out somewhere around mile 18.
Luckily, none of it is a surprise on race morning. The forecast is available ten days out, and CarbRate reads it for you.
Heat changes your fluid. It does not change your carbs
Almost every hot-weather fueling article tells you to eat less when it is hot. It is the most repeated piece of bad advice in the sport.
Your carbohydrate target is set by , not by how hot it is.
What heat actually moves is how much you sweat, how much you therefore need to drink, the sodium concentration that fluid carries, and how long the race takes you.
And because heat makes the race longer, you will take in more total grams at the same rate per hour.
There is one more thing heat does, and it is the useful one.
As your fluid goes up, more of your carbohydrate can come out of the bottle instead of out of a gel, so you take fluid and fuel together and your stomach has less to deal with.
Doing all of that yourself means a heat-balance calculation, a sodium concentration, and re-timing every feed against a finish time that just moved.
That is why CarbRate re-runs the entire plan against the forecast, and then shows you only the lines that actually moved.
CarbRate swaps your assumed weather for the real forecast ten days out
Until then your plan runs on the temperature and humidity you entered, or on a mild default if you skipped the question. Both are labelled as estimates.
Inside ten days, CarbRate pulls the actual forecast for your race location and reads race morning specifically.
It takes the hottest hour of your race window rather than the daily average, which is the safe direction to be wrong in.
You do not have to remember to check anything. The plan tells you when the weather has moved enough to matter.
CarbRate shows you every number the weather moved, before you accept it
A plan that silently rewrites itself is a plan you stop trusting.
So the forecast card is read-only until you tap it, and what it shows you is a diff.
Expected sweat loss 1.1 to 1.3 litres an hour. Sweat band 1.0 to 1.3 becomes 1.2 to 1.5. Drink sodium 800 to 850 milligrams a litre. Projected finish moves, and the number of feeds moves with it.
Carbohydrate is missing from that list on purpose, because carbs are set by how long you run and not by how hot it is.
Accepting it writes a new version of your plan rather than editing the old one, so you can always see what changed and when.
CarbRate tells you when you cannot drink your way out of the heat
On the hottest days there is a point where fluid cannot keep up with what you are losing.
Most plans stay quiet about that and give you a bigger number to drink.
CarbRate says it plainly instead: you cannot replace these losses by drinking.
And it gives you the only honest answer, which is to run the early miles slower than the goal you wrote down.
You get that in your kitchen ten days out, with time to change your race plan, instead of learning it at mile 16.
CarbRate carries the forecast all the way into race week
In the last week the forecast firms up, and the plan firms up with it.
CarbRate hands you a version you can look over, then turns it into the jobs that are left.
How much to eat on each loading day, what to buy, and the morning-of plan with wake-up time, breakfast and the pre-race gel already on it.
By the time you are standing in the corral, every number in your plan was built on the weather you are actually standing in.
Cold race? Checking it yourself?
You cannot pick the weather. You can stop being surprised by it
You are going to refresh that forecast a dozen times in race week anyway.
CarbRate is the only part of your race prep that does something with it.
- Fueling plan built on your exact course
- Personalized to your sweat rate, weight, and goal
- Adjusts when the race-day forecast moves
- Week-by-week gut-training practice schedule
- One prescribed change after every rough run
- The dress-rehearsal run, scheduled early
- Live guidance through every gel and drink
- All 163 gels, chews, and mixes built in
See how CarbRate handles the rest of your race
A page for each one: