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Fueling well is the difference between a finish and a DNF in most ultras. The Fuel step turns abstract goals (“I want to eat 75 g/h of carbs”) into a concrete plan (“1 Maurten gel every 45 minutes from start to finish”) that the mobile app fires as reminders on race day. The step has two halves: Fueling Targets (the hourly numbers, scaled for conditions and effort) and Fueling Strategy (the actual rules and items that deliver them). Iterate between the two: set targets, plan rules, check whether actuals match, refine.

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Fueling Targets

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Weather

Conditions you expect on race day. Drives sweat-rate scaling, fluid + sodium targets, and per-segment temperature-adjusted intake.
  • Constant Weather — manual pick from a temperature band (cold / cool / mild / warm / hot / very hot). Use when no forecast is available or when you want a fixed worst-case scenario.
  • Weather Forecast — pulls the actual hour-by-hour forecast for the race date set in Plan Details. Feeds segment-by-segment temperatures across the day.

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Body Metrics

Per-runner inputs that scale the targets:
  • Body weight — drives the per-kg components of carb and fluid targets.
  • Sweat rate — litres of fluid lost per hour at race effort. Default ~1 L/h mild, up to 1.4 L/h hot. Scales with the Weather temperature band.
  • Sweat sodium concentration — milligrams per litre. Default ~800 mg/L; salty sweaters run 1,200+ mg/L.
  • GI tolerance — bounds the carbs-per-hour ceiling. Trained guts can push past 90 g/h; untrained stomachs cap closer to 60.
Defaults come from your Plan Defaults. Override per plan when conditions or your race form demand it.

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Fueling Targets (the hourly numbers)

The headline values, derived from Weather + Body Metrics:
  • Carbs per hour — 60–100 g/h for ultra distance with a trained gut.
  • Fluid per hour — 400–800 ml depending on conditions and sweat rate.
  • Sodium per hour — 300–800 mg, higher for hot conditions and salty sweaters.
  • Calories per hour — 200–400 cal/h.
  • Caffeine per hour — optional, capped at safe daily totals.

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Segment Targets

Per-segment adjustments based on the route’s terrain and the weather forecast. Hot exposed segments need more fluid; technical climbs need fewer gels because you can’t open them while scrambling. The planner suggests adjustments automatically, and you can tweak each segment’s targets manually.

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Fueling Strategy

The execution half. Targets tell you what you need; Strategy is how you’ll deliver it. The chart shows every planned intake along the course distance. Below it, a list lets you add and edit rules and items. A totals row compares your actuals against the targets so you can spot under- or over-shoot at a glance.

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Fuel Rules vs. Fuel Items

  • Fuel Rule — a REPEATING intake. Same item, same schedule across a window. “1 gel every 45 minutes from start to finish” → ~16 reminders across a 12-hour race.
  • Fuel Item — a ONE-OFF intake. Single scheduled event, no repeat. “100 mg caffeine pill at minute 360” → one reminder when fatigue is about to bite.

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Configuring a rule

  • Frequency — every (recurring), at (single trigger), or at every checkpoint.
  • Measure type — time (every 45 min), distance (every 5 km), or checkpoint (at every aid station that offers gels).
  • From / To — bound the rule to a window. Useful for starting fueling later (let your stomach settle), stopping earlier (last 30 min before finish), or restricting to a specific segment.
  • Consume with (chaser) — optional companion item. Take a gel with 200 ml of water; salt cap with 250 ml fluid. The mobile app surfaces both in one reminder.
  • Portion size / Split mode — log fractions (½ bar) or spread a dose evenly through a window (a sandwich in 4 bites across km 60–80).

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Per-segment actuals vs. targets

Each segment shows its own actual totals from your rules + items compared against Segment Targets. Green = on plan; red = under or over for that segment. Click a flagged segment to jump to its per-segment view and refine.

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Checkpoint refill suggestions

When a checkpoint has matching offerings (water, cola, gels) declared on the route checkpoints, the planner suggests refills there instead of asking you to carry everything from the start. Refills surface inline with your rules — they’re not a separate editor, just a recommendation you can accept by adding the matching rule.

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The iteration loop

Targets → Rules + Items → Actuals → compare → adjust. Most plans take 2–3 passes:
  1. Set a coarse rule (“1 gel every 45 min”).
  2. Read actuals — say carbs come in at 50 g/h against a 75 g/h target.
  3. Layer items into the gaps (“Cola at every aid station”).
  4. Re-read; actuals land around 70 g/h.
  5. Bump gel quantity to 1.5 → on target.

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What becomes a mobile-app reminder

Every rule and every item turns into a scheduled notification on race day. Each reminder shows the item, quantity, and any chaser. Acting on it marks it consumed; ignoring it logs a miss. The actuals you tuned against in Fueling Strategy are exactly what gets delivered.
Don’t go above your trained intake on race day. The plan is only as good as what your gut can handle — test the targets on long training runs first.

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Next

Last step: Dropbags & Tasks for what’s in each bag and what you need to do at each checkpoint.