Privacy Policy

Last updated: October 2025

1. Information We Collect

1.1 Health and Fitness Data

LyteFast integrates with Apple HealthKit to collect and store the following health data:

• Weight data: Current weight, weight history, and weight goals
• Height data: Your height for BMI calculations
• Activity data: Steps, active calories, and exercise information
• Nutritional data: Food intake, calories consumed, and macronutrient information
• Body measurements: Body fat percentage and other biometric data (if available)

1.2 User-Provided Information

• Profile information: Age, gender, activity level, and fitness goals
• Food logging: Manual food entries, photos of meals, and voice notes
• Preferences: Unit preferences (metric/imperial), language settings, and app customization

1.3 Usage Data

• App usage: Features used, time spent in app, and interaction patterns
• Performance data: Crash reports and app performance metrics
• Device information: Device type, operating system version, and app version

2. How We Use Your Information

2.1 Core App Functionality

• Calculate personalized calorie targets and weight loss projections
• Track your nutrition and fitness progress over time
• Provide insights and recommendations based on your data
• Sync data across your devices using iCloud

2.2 AI-Powered Features

LyteFast uses artificial intelligence to enhance your experience:

• Food Recognition: We use OpenAI's GPT-4 Vision API to analyze food photos and estimate nutritional content
• Nutritional Analysis: USDA Food Data Central API provides comprehensive nutritional information

2.3 Data Processing and Storage

• Local Storage: Your health data is primarily stored locally on your device using SwiftData
• iCloud Sync: Data is encrypted and synced across your Apple devices
• Temporary Processing: Food photos are temporarily uploaded to secure cloud storage for AI analysis, then deleted

3. Third-Party Services

3.1 OpenAI API

We use OpenAI's GPT-4 Vision API to analyze food photos and provide nutritional estimates. When you take a photo of food:

• The image is temporarily uploaded to our secure backend server
• OpenAI processes the image to identify food items and estimate portions
• The image is automatically deleted from our servers after processing
• No personal information is shared with OpenAI beyond the food image

3.2 USDA Food Data Central API

We use the USDA Food Data Central API to provide accurate nutritional information:

• Food search queries are sent to USDA's database
• Nutritional data is retrieved and displayed in the app
• No personal information is shared with USDA

3.3 OpenFoodFacts API

We use the OpenFoodFacts API for barcode scanning and product information:

• Barcode scans are sent to OpenFoodFacts database for product lookup
• Product names and nutritional data are retrieved when available
• This is a free, open-source database with no API key required
• No personal information is shared with OpenFoodFacts

3.4 Apple Services

• HealthKit: For reading and writing health data
• iCloud: For syncing data across devices
• AVFoundation: For camera access and barcode scanning

3.5 Backend Image Processing

We use a secure backend service for temporary image processing:

• Food photos are temporarily uploaded to our secure backend server
• Images are processed for AI analysis and then automatically deleted
• All data transmission is encrypted using HTTPS/TLS
• No images are stored on our servers at all

4. Data Security

4.1 Encryption

• All data transmission uses HTTPS/TLS encryption
• Health data is encrypted using Apple's HealthKit encryption
• iCloud data is encrypted using Apple's end-to-end encryption

4.2 Access Controls

• Only you have access to your health data stored locally
• Our backend servers use secure authentication and access controls
• Third-party API access is limited to necessary functionality only

5. Your Rights and Controls

5.1 Data Access and Portability

• Export your data through Apple Health app
• View all stored data within the LyteFast app
• Request a copy of your data by contacting us

5.2 Data Deletion

• Delete individual food entries and health data within the app
• Uninstall the app to remove all local data
• Contact us to request complete data deletion from our systems

5.3 Privacy Controls

• Control HealthKit permissions in iOS Settings
• Disable iCloud sync in app settings
• Opt out of analytics and crash reporting

6. Children's Privacy

LyteFast is not intended for children under 13. We do not knowingly collect personal information from children under 13. If you are a parent or guardian and believe your child has provided us with personal information, please contact us immediately.

7. International Users

If you are using LyteFast from outside the United States, please note that your information may be transferred to, stored, and processed in the United States where our servers are located. By using our app, you consent to the transfer of your information to the United States.

8. Changes to This Privacy Policy

We may update this Privacy Policy from time to time. We will notify you of any changes by posting the new Privacy Policy on this page and updating the "Last updated" date. You are advised to review this Privacy Policy periodically for any changes.

9. Contact Information