Fuel Rehearsal Builder
A practice timeline to test in training — never a race-day prescription.
Race-day fuelling fails when it is attempted for the first time on race day. This builder gives you a duration-based practice timeline to rehearse in training, so you find out what your gut tolerates while a bad session costs you an afternoon rather than a race. Every number is a starting range to test and adjust, not a prescription.
Practice plan — requires coach review before race use
Rehearsal plan: 30–60g carbs and 450–700ml fluid per hour
A 2-hour rehearsal with feeds every 20 minutes. Take this into a training session at race intensity, log what happens, and bring the log to a coach or accredited sports dietitian before you race it.
Read this first
This is a rehearsal plan for a TRAINING session. Do not use it in a race until you have practised it and had it reviewed by a coach or accredited sports dietitian.
Do not exceed 1000ml of fluid per hour. Over-drinking causes exercise-associated hyponatraemia — dangerously diluted blood sodium — which is a more serious risk in endurance events than mild dehydration. Drink to thirst within the range above.
Nothing new on race day. That includes brands, flavours and concentrations, not just product types.
Your gut is untested, so this plan deliberately starts at the low end. Gut tolerance is trainable, but it is built over weeks — increase by roughly 10g per hour every second week, and only if the previous step caused no symptoms.
Your hourly starting ranges, against the safety caps
The bar is your starting range. The marked line is the absolute cap — the rehearsal is for finding where inside your range you sit, never for pushing past the cap.
View as a table
| What | Per hour | Absolute cap | Notes |
|---|---|---|---|
| Carbohydrate | 30–60g/h | 90g cap | Held at the low end because your gut is untested. Build up over weeks, not sessions. |
| Fluid | 450–700ml/h | 1000ml cap | Guided by thirst. Exceeding the cap risks hyponatraemia. |
| Sodium | 500–700mg/L | — | Per litre of fluid consumed, not per hour. |
Ranges, not prescriptions. Where you sit inside them is what the rehearsal is for.
Feed schedule across the 2-hour session
Feeds every 20 minutes. Set a repeating alarm — under fatigue, nobody remembers to eat on schedule.
View as a table
| Time | Kind | What happens |
|---|---|---|
| 0:00 | Weigh-in | Start — weigh in |
| 20:00 | Feed | Feed 1 |
| 40:00 | Feed | Feed 2 |
| 1:00:00 | Feed | Feed 3 |
| 1:20:00 | Feed | Feed 4 |
| 1:40:00 | Feed | Feed 5 |
| 2:00:00 | Weigh-in | Finish — weigh in |
The timeline in detail
- T–2hPre-session mealRoughly 70–140g of carbohydrate, low in fibre and fat, with 400–600ml of fluid. Eat what you would eat before a race — this is part of the rehearsal.
- 0:00Start — weigh yourself firstWeigh yourself naked immediately before starting and note the number. This is how the session measures your real sweat rate rather than guessing at it.
- 20:00Feed 110–20g carbohydrate · 150–225ml fluid. Log how your stomach feels on a 1–5 scale before you take it.
- 40:00Feed 210–20g carbohydrate · 150–225ml fluid. Log how your stomach feels on a 1–5 scale before you take it.
- 1:00:00Feed 310–20g carbohydrate · 150–225ml fluid. Log how your stomach feels on a 1–5 scale before you take it.
- 1:20:00Feed 410–20g carbohydrate · 150–225ml fluid. Log how your stomach feels on a 1–5 scale before you take it.
- 1:40:00Feed 510–20g carbohydrate · 150–225ml fluid. Log how your stomach feels on a 1–5 scale before you take it.
- 2:00:00Finish — weigh yourself againWeigh yourself naked again, towelled dry. Every kilogram lost is roughly a litre of sweat you did not replace. Add what you drank to the weight lost, divide by the hours, and you have your actual hourly sweat rate — the number that replaces the guess you made at the top of this form.
Translating that into what you actually carry
Roughly 15g per feed. A practical mix is drink mix as the base with a gel at the harder points — that way fluid and carbohydrate scale independently.
What to log — this is the part that makes it a rehearsal
- Body weight before and afterNaked, towelled dry, same scales. Weight lost plus fluid drunk, divided by hours, is your true sweat rate.
- Gut comfort at every feed, 1–5Record it at the moment, not from memory afterwards. A pattern across three sessions is data; one bad session is weather.
- Energy through the sessionNote where you felt strong and where you faded. Fading late usually means too little carbohydrate too late, not too little fitness.
- Exactly what you tookBrand, flavour, concentration, timing. "A gel at about an hour" is not a repeatable plan.
Tri Alliance sessions that close these gaps
- Coach or accredited sports dietitian review Mandatory before this plan is used in a race. Bring your rehearsal log with you.
- Brick session (bike into run) The right session to rehearse fuelling in — race intensity, and the run leg is where gut problems actually show up.
This is a training rehearsal guide, not medical or dietetic advice. It cannot account for your medical history, medications or individual requirements. Every plan produced here must be reviewed by a Tri Alliance coach or an accredited sports dietitian before you act on it in a race.
The short answer
Endurance fuelling should be rehearsed in training, never attempted for the first time on race day. General starting ranges for athletes without medical conditions are 30–60g of carbohydrate per hour for efforts under two hours and 60–90g per hour beyond that, with fluid guided by thirst and typically 400–800ml per hour depending on sweat rate and heat. Exceeding roughly 1000ml of fluid per hour risks exercise-associated hyponatraemia. Gut tolerance for higher carbohydrate intakes is trainable but must be built progressively over weeks. Any individual plan should be reviewed by a coach or accredited sports dietitian.
How to use this tool
- Declare any medical condition, medication or dietary requirement first — if any apply, the tool routes you to a professional instead of generating a plan.
- Enter the duration of the session you are rehearsing, your body weight, sweat rate and expected conditions.
- Tell the tool how much fuelling practice your gut has actually had. Untested guts start low.
- Take the timeline into a TRAINING session, not a race. Log what happened at each checkpoint.
- Have a coach or accredited sports dietitian review the plan and your logged results before you use it in a race.
Common questions
How many carbs per hour should I take in a triathlon?
General starting ranges are 30–60g of carbohydrate per hour for efforts under two hours, and 60–90g per hour for longer efforts. If you have never practised fuelling, start at the bottom of the range — an untrained gut commonly rejects 60g per hour even though the athlete is fit enough to use it. Tolerance for higher intakes is trainable over several weeks. These are population ranges; individual requirements vary and should be reviewed by a qualified professional.
How much should I drink during a triathlon?
Drink to thirst, typically within a 400–800ml per hour range depending on sweat rate and heat. Do not exceed roughly one litre per hour. Over-drinking causes exercise-associated hyponatraemia — dangerously diluted blood sodium — which is a more serious risk in endurance events than mild dehydration. Weighing yourself before and after a session is the only reliable way to know your actual sweat rate.
Why do I get stomach problems during races?
The most common causes are attempting an intake your gut has never practised, taking in too concentrated a mix of carbohydrate and too little fluid, and starting fuelling too late so you are playing catch-up. Blood flow diverts away from the gut under hard efforts, which reduces what you can absorb. The fix is rehearsal: practise your exact race intake in training sessions at race intensity.
When should I practise my race nutrition?
Rehearse in your longer training sessions, at race intensity, starting at least six to eight weeks before the race, and use the exact products you will race with. The rule is nothing new on race day — including brands, flavours and concentrations. Log gut comfort at each feed so you have data rather than an impression.
Should I take caffeine during a race?
Caffeine has good evidence for endurance performance, commonly at around 3mg per kilogram of body weight taken 45–60 minutes before it is needed. It must be rehearsed — caffeine increases gut motility and anxiety in some athletes, and race day is not the time to discover you are one of them. Anyone with a cardiac condition, on medication, or who is pregnant should not take performance caffeine without medical advice.