The watch companion exists for speed. It helps you capture nutrition inputs and workout context in the moment so your targets and coaching are built from real data.
01What the watch companion is for
On Apple Watch, Fuel focuses on actions that benefit from being immediate.
Wrist quick log is the core workflow. It is designed for repeated meals, post training routines, and the kind of small actions that get skipped when the phone is not nearby.
The watch also supports weight logging, hydration, fasting, workouts, sauna sessions, Health Grade, recent activity, and sync status. Use it when the phone would slow down the capture.
02Installing the watch app
Fuel installs on Apple Watch through the iPhone Watch app.
- Install Fuel on iPhone and open it once
- Open the Watch app on iPhone
- Scroll to Available Apps, find Fuel, then tap Install
If Fuel is already listed under Installed on Apple Watch but you cannot find it on the watch, restart both iPhone and Apple Watch, then check again.
03Watch face complications
Fuel supports watch face complications so the day stays visible without opening the app.
- Press and hold your watch face
- Tap Edit
- Swipe to the complications screen
- Tap a complication slot and select Fuel
The configurable metric complication can show calories, protein, macros, water, fasting, sauna, Health Grade, or streak. Fuel also includes fixed complications for Calories Left, Water, Streak, and Macro Focus. They update based on the most recent watch and iPhone sync, so treat them as a glanceable summary, not a live meter.
Use Streaks to understand what counts toward the streak counter.
04Wrist quick log workflow
Quick log is not a separate diary. It is a faster capture path that syncs back into the same Apple Health nutrition record stream.
- Log a meal or item from the watch when you need the entry recorded immediately.
- Use undo if you tapped the wrong entry or logged the wrong time window.
- Confirm or refine the entry on iPhone when you want higher precision.
05Corrections and accuracy
Treat watch logging as the first pass. The goal is a stable daily record, not perfect restaurant grade measurement in the middle of a busy day.
If an entry needs a correction, make it the same day so daily review and weekly coaching do not learn from an error that you already know about.
06Weight logging from the watch
The watch companion includes a weight screen for quick weigh-ins. It starts from your last known weight and preferred unit, then syncs the entry back to the same weight history used on iPhone.
Use the watch for routine weigh-ins. Use iPhone when you need to review the trend, edit past entries, or change units.
07When to switch back to iPhone
Use iPhone for photo based logging, recipe details, and any edit where you want full context. The watch is a capture surface, not the place for long form planning.
08Water logging from the watch
The watch companion includes a hydration view for logging water without reaching for your phone. Tap to add common amounts and see your progress toward the daily target. The entry syncs back to the same Hydration record on iPhone.
09Fasting timer on the watch
The fasting view mirrors the fasting tile on Today. It shows your current fasting stage, time elapsed, and estimated calories burned. If you use fasting notifications, they also appear on the watch. See Fasting for how fasting stages work.
10Workout logging from the watch
You can start and log workouts directly from the watch. Choose a preset such as walk, run, cycling, strength, HIIT, or Other, set the duration, and the entry syncs to Apple Health and appears in your Energy Balance. For workouts already tracked by Apple Watch natively, Fuel reads them automatically through Apple Health without double counting.
If App Preferences maps Apple Health Other workouts to Sauna, Fuel presents those matching entries as sauna context across Today, Watch, and coaching.
11Sauna sessions from the watch
Sauna has its own watch flow. Start a session, set the temperature when needed, and watch elapsed time, estimated calories, and heart rate during the session.
When you end the session, Fuel syncs the sauna entry back to iPhone and writes compatible workout data to Apple Health when permissions allow. Use the dedicated sauna flow for heat sessions instead of treating them as generic workouts.
12Health Grade, recent activity, and sync
The Health Grade screen shows the current grade and contributor context from the watch. Recent Activity shows the latest logged items and training entries. Sync Status shows whether the watch has fresh iPhone data and gives you a place to request a sync when the watch looks stale.
13Watch widgets
Fuel supports Smart Stack widgets and controls on Apple Watch for quick glances and fast actions. Hydration, Fasting, and Next Action widgets are separate from watch face complications. Hydration, Quick Log, and Workout controls are separate from both.
