1. AI-Powered Nutrition Analysis
fuelOS uses Google Gemini, a large language model (LLM), to analyze your meal photos and descriptions to estimate nutritional content.
What gets sent to Google:
- Photos of your meals (compressed JPEG images)
- Text descriptions you provide
- Voice transcriptions (converted to text first via Deepgram)
What Google returns:
- Estimated calories
- Estimated macronutrients (protein, carbs, fat)
- Estimated micronutrients (vitamins, minerals)
- Meal name and description
2. How Accurate Is It?
AI nutrition estimates are approximations, not exact measurements. Accuracy depends on:
- Photo quality and angle
- Food visibility and portion size clarity
- Complexity of the meal (homemade vs. packaged foods)
- Description detail you provide
Use fuelOS for: General tracking, identifying patterns, and awareness of eating habits.
Do not use fuelOS for: Medical decisions, strict dietary requirements, or clinical nutrition needs.
3. Voice Transcription
When you use voice input, your audio is sent to Deepgram's speech recognition API:
- Audio is sent over encrypted connections
- Transcription happens in real-time
- Audio is not stored by Deepgram after transcription
- The resulting text is then sent to Google Gemini for nutrition analysis
4. Data Retention by Third Parties
Google Gemini:
- We use Google's API in a way that does not allow them to use your data to train their models
- Images and text are processed for analysis only
- See Google's Privacy Policy for their data handling practices
Deepgram:
5. How Your Data Is Stored
Meal Photos: If you sign in, your meal photos are stored securely in Firebase Storage (Google Cloud) solely to display your meal history within the app and sync across your devices. Photos are associated only with your authenticated account and are not accessible to anyone else.
Voice Recordings: Audio is processed in real-time for transcription and is not stored. Only the resulting text transcription is retained as part of your meal entry.
6. What We Don't Do
fuelOS does not:
- Use your data to train AI models (ours or third-party)
- Share your data with advertisers or data brokers
- Analyze your data for marketing or profiling purposes
- Allow any third party to access your meal photos or personal data
- Retain voice recordings after transcription
Your data exists solely to provide you with the fuelOS service. It is not monetized, analyzed, or used for any purpose other than showing you your own nutrition information.
7. Apple Health Integration
There are two separate Apple Health features, with different data paths:
Meal sync (write-only, on-device). Nutrition estimates are written to your local Apple Health database. Nothing leaves your device for this sync.
Comprehensive Data Sync (opt-in, off-device). If you turn it on, fuelOS keeps a continuous cloud copy of new Apple Health data, in the categories you approve on Apple's permission sheet, starting from the moment you enable it. Data recorded before that moment stays on your device and is never uploaded.
Why health data is readable on our servers
Apple keeps Health data on-device. For an AI to answer questions about your health, it has to read the data where the AI runs, which is on our servers. The cloud copy is encrypted in transit and at rest, but it is not end-to-end encrypted: fuelOS systems read it to serve your AI, and for nothing else.
- You choose the categories. Apple's permission sheet controls exactly what syncs. Reproductive health, mental wellbeing, and GPS routes are never in the default request; each is a separate opt-in.
- It is used for your insights only. Your health data is never sold, never shared with advertisers or data brokers, and never used to train models.
- You can see what it holds. The app shows live counts of exactly what is stored, and a periodic integrity check verifies the cloud copy against your device.
- You can take it out. Export downloads every record as one open-format archive (gzipped NDJSON).
- Deletion is verified. Deleting your cloud copy re-checks the storage afterwards and shows you a receipt confirming zero bytes remain. Account deletion runs the same purge.
- Infrastructure: Amazon Web Services (US East) for storage; Google Firebase for sync bookkeeping. No other processors touch it.
8. Your Control
You are in complete control:
- Delete meals: Swipe to delete any meal from your history
- Delete account: Settings → Delete Account permanently deletes all your data, including any health cloud copy
- Disable features: Turn off Comprehensive Data Sync or delete the app entirely
9. Questions?
If you have questions about our AI usage or data practices, contact us at: ai@fuelos.site
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