Frequently Asked Questions
Find answers to common questions about FuelFlow.
Getting Started
What is FuelFlow?
FuelFlow is a nutrition tracking app designed for endurance athletes. It helps you monitor carbohydrate, sodium, caffeine and water intake in real-time during training and competition across multiple sports including running, cycling, triathlon, and other endurance activities, with seamless integration between iPhone and Apple Watch.
What devices do I need?
FuelFlow works on:
- iPhone running iOS 18.6 or later
- Apple Watch running watchOS 26.0 or later
- iCloud account for syncing between devices
You can use FuelFlow on iPhone only, but the Apple Watch companion app provides the best experience for logging nutrition while running.
How much does FuelFlow cost?
FuelFlow offers a monthly or yearly plan. $4.99/mo or $39.99 a year
Do I need an internet connection?
No! FuelFlow works completely offline. When your iPhone and Apple Watch are together, they sync instantly via Bluetooth—no internet required. Your data will also automatically sync to iCloud when you have an internet connection, but you can log nutrition and track your activities with zero connectivity.
Using FuelFlow
How do I start an activity?
- Open FuelFlow on your iPhone or Apple Watch
- Tap “Start Activity”
- Select your activity type (Running, Cycling, or Triathlon)
- Set your hourly goals for carbs, sodium, and water (or use defaults)
- Begin logging your nutrition as you consume it
How do I log food during a run?
On Apple Watch:
- Raise your wrist to wake the watch
- Tap the food item you consumed
- That’s it! The app logs it instantly with a timestamp
On iPhone:
- Tap “Log Food”
- Select the food item from your library
- The consumption is logged immediately
What are the default nutrition goals?
- Carbs: 60g per hour
- Sodium: 500mg per hour
- Water: 0.5L per hour
These are based on common ultrarunning guidelines, but you can adjust them based on your personal needs and race conditions.
Can I customize my goals during an activity?
Yes! You can adjust your hourly goals at any time during an active session. This is useful if conditions change (heat, altitude, effort level) or if you need to adjust your fueling strategy mid-event.
How does the food library work?
FuelFlow comes pre-loaded with common endurance nutrition items including:
- Energy gels from major brands
- Nutrition bars and chews
- Sports drinks and electrolyte mixes
- Real food options
- Sport-specific nutrition items
You can also add custom food items with your own carb counts, sodium content, and serving sizes tailored to your sport.
Can I edit or delete food items?
Yes! You have full control over your food library. You can:
- Add new custom items
- Edit existing items (including pre-loaded ones)
- Delete items you don’t use
- Organize by category (Gel, Food, Drink)
Data & Sync
How does syncing work between devices?
FuelFlow uses a sophisticated dual-sync system:
Instant Sync (Primary): When your iPhone and Apple Watch are connected via Bluetooth or WiFi, changes sync near instantly. Log a gel on your Watch, and it appears on your iPhone immediately—no internet required! This works even in airplane mode with Bluetooth enabled.
CloudKit Sync (Backup): When devices aren’t in Bluetooth range, FuelFlow automatically uses iCloud to sync. Any changes to your food library, sessions, or goals sync across all your devices signed in with the same iCloud account.
The dual-sync system ensures you never lose data, whether your devices are together or apart, online or offline. Learn more in our Sync & Data Guide.
Do I need internet for sync during activities?
No! When your iPhone and Apple Watch are connected via Bluetooth (typical range: about 10 meters / 30 feet), instant sync works with zero internet. This is perfect for:
- Remote trail runs without cell service
- International races (no roaming charges)
- Airplane mode to save battery
- Any area with spotty connectivity
What if I’m in airplane mode during a race?
No problem! Just enable Bluetooth even with airplane mode on:
- Enable Airplane Mode
- Manually turn Bluetooth back on
- Instant sync continues to work between iPhone and Watch
- No internet or cellular data used
- Maximum battery life with full sync functionality
When you disable airplane mode later, CloudKit will sync any changes as a backup.
Can I use FuelFlow on multiple iPhones or Apple Watches?
Yes, as long as all devices are signed in with the same iCloud account. Your food library and run history will stay in sync across all devices.
Is my data private?
Absolutely. Your nutrition data is stored in your private iCloud account. FuelFlow doesn’t have access to your data, and we never share information with third parties. No ads, no tracking.
Can I delete my data?
Yes. You can delete individual food items, run sessions, or all your data directly from the app. You can also manage your iCloud data through your device settings.
During Your Activity
What if I forget to log something?
After your activity, you can review your consumption log with timestamps. You can also edit past entries to make your file reflect reality.
How accurate is the hourly breakdown?
Very accurate! FuelFlow tracks consumption down to the second and calculates rates based on actual elapsed time, not just rounded hours. This means if you’re 30 minutes into hour 2, it calculates your rate based on 1.5 hours, not 2 hours.
Can I see my progress in real-time?
Yes! Both the iPhone and Apple Watch show live progress bars for carbs, sodium, and water, displaying your current consumption versus your hourly goals. This works across all activity types.
What if I forget to end my activity?
No worries! You can end an activity at any time, even hours or days later. You can edit the end time by attaching a GPX or workout file to it, FuelFlow will adjust the start and end times to match.
After Your Activity
How do I export my activity data?
- Go to the “Export” or “Past Activities” section
- Select the activity you want to export
- Tap “Export Report”
- Share via Messages, Mail, AirDrop, or save to Files
What’s included in the export?
The exported report includes:
- Activity type and duration
- Date and time
- Total consumption (carbs, sodium, water)
- Overall average rates per hour
- Detailed hourly breakdown
- Complete consumption log with timestamps
Can I compare multiple activities?
The app displays your past activities in a list, organized by activity type. While there’s no built-in comparison feature yet, you can export multiple activities and analyze them side by side.
How long is activity data stored?
Your activity data is stored indefinitely in your iCloud account until you choose to delete it.
Troubleshooting
FuelFlow isn’t syncing between my devices
First, check instant sync (if devices are nearby):
- Ensure Bluetooth is enabled on both iPhone and Watch
- Bring devices within Bluetooth range (about 10 meters / 30 feet)
- Open FuelFlow on both devices to trigger sync
- Wait a moment—sync happens in less than 1 second
If still not syncing, check CloudKit sync:
- Ensure you’re signed in to iCloud on both devices
- Verify you have an internet connection
- Check that iCloud Drive is enabled in Settings
- Try force-quitting and reopening the app
- Wait 10-30 seconds for CloudKit sync to complete
Most sync issues are resolved by simply ensuring Bluetooth is enabled and devices are in range. See our Sync & Data Guide for detailed troubleshooting.
Session started on iPhone isn’t showing on Watch
Quick fix:
- Check that Bluetooth is enabled on both devices
- Open FuelFlow on your Apple Watch
- Pull down to refresh
- Session should appear immediately
If still not appearing, check internet connection for CloudKit sync as backup.
My Apple Watch app isn’t showing my food library
First, make sure your iPhone and Apple Watch are syncing. The food library is managed on iPhone and syncs to the Watch. If items aren’t appearing, try:
- Using the manual sync feature on the food library page to force a complete CloudKit refresh
- Opening FuelFlow on iPhone to trigger an automatic sync
- Ensuring both devices have an internet connection
- Restarting both devices
I’m not receiving progress updates
Make sure you have an active run session started. Progress bars only appear during an active run. If you have a run active but aren’t seeing updates, try:
- Force-quitting and reopening the app
- Checking that your goals are set to reasonable values
- Logging at least one item to see the progress update
The app is using too much battery on my Watch
To conserve battery during long runs:
- Lower your Watch’s screen brightness
- Use Theater Mode to prevent accidental wake-ups
- Disable unnecessary Watch complications
- Consider using Low Power Mode for runs over 6 hours
Event Day Tips
Should I test FuelFlow before event day?
Absolutely! Use FuelFlow during your training sessions to:
- Get comfortable with the interface
- Build your food library with your preferred nutrition
- Dial in your hourly goals for different activity types
- Practice logging while in motion
What’s the best way to use FuelFlow during long endurance events?
- Pre-load your food library with everything you plan to consume
- Select the correct activity type at the start (Running, Cycling, Triathlon, etc.)
- Set conservative goals - it’s better to over-fuel than under-fuel
- Use the Apple Watch for quick logging without stopping
- Check your hourly breakdown at aid stations or rest stops to adjust strategy
- Don’t stress over perfect logging - it’s a tool to help, not add pressure
Can my crew, pacer, or support team help with logging?
While the app is designed for solo use, your support team can help by:
- Reminding you to log nutrition
- Checking your progress at aid stations or feed zones
- Helping you adjust goals based on how you’re feeling
- Reviewing hourly data to identify fueling issues
Feature Requests & Feedback
How do I suggest a new feature?
We love hearing from users! Email your suggestions to info@fuelflow.run. Popular requests that align with our mission of simple, fast nutrition tracking will be considered for future updates.
Can you add [specific food brand/item]?
While we can’t add every food item to the default library, you can easily add custom items yourself. If you think a food should be in the default library, let us know at info@fuelflow.run.
Will you add training plans or workout tracking?
FuelFlow is laser-focused on nutrition tracking during endurance activities. We intentionally don’t include workout tracking, training plans, or other features to keep the app simple and fast. There are excellent apps for those purposes (Strava, TrainingPeaks, etc.) that complement FuelFlow’s nutrition tracking capabilities.
Still Have Questions?
Can’t find the answer you’re looking for? Contact us:
- General Questions: info@fuelflow.run
- Technical Support: support@fuelflow.run