Train, eat and track in one.
Last updated: 5 August 2026
One4 is a fitness app. We collect as little as we can, we don't run ads, we don't use analytics or tracking SDKs, and we never sell your data. This policy explains what we store, where it goes, and how to delete it.
You can track workouts, nutrition and body metrics without signing in. That data is stored only on your device, and we cannot see it.
Signing in with email, Google or Apple creates an account so you can back up your data and use the AI features. We store your user ID, the sign-in method, and your email address if your provider gives us one. Authentication is handled by Google Firebase Authentication.
If you are signed in, a copy of your training programmes, workout history, body metrics (weight, height, body fat, muscle, visceral fat), nutrition targets, food log and custom exercises is stored in our database (Google Cloud Firestore) under your account. Only you can read it: our security rules restrict each account to its own data.
Backup happens when you tap “Back up now”, and also automatically when you leave the app, so your data survives a lost or replaced phone. Automatic backup is on by default and can be turned off at any time in Settings › Account & sync. Backup only ever uploads; restoring from your backup replaces the data on your device, and only happens when you ask for it.
When you use the AI Coach, scan or estimate a meal, generate a programme, or set nutrition targets, One4 sends the relevant information to Google’s Gemini API to produce a response. Depending on the feature this may include: meal photos you choose to scan, photos of body composition printouts (such as an InBody sheet) you choose to scan, the text you type, your fitness goal, and body metrics such as weight, height, body fat, BMI and muscle where available. Requests pass through our own proxy server (hosted on Cloudflare), which attaches our API key, checks your remaining daily allowance, and forwards the request. The proxy stores your account ID with a daily request count and your subscription status so limits can be enforced; it does not store the content of your requests. Google processes requests under its own API terms. This data is used only to generate your result — never for advertising.
If you turn on Apple Health, One4 reads your weight, height, body fat, steps and active energy, and writes your workouts, nutrition and body metrics back to Health. This is optional and can be turned off in Settings. Health data is used on your device and, if you use the features above, may be included in cloud backup or sent to the AI as described.
When you scan a product barcode, only the barcode number is sent to Open Food Facts (openfoodfacts.org) to look up nutrition information. No personal data is included.
Camera is used for meal photos, body composition printouts and barcode scanning. Notifications are used for rest-timer alerts. Apple Health is used for the sync described above. All are optional, requested only when first needed, and the app works without them.
You can delete your account at any time in Settings › Account & sync › Delete account. This permanently removes your cloud backup and your sign-in account. Daily AI request counts held by our proxy expire automatically within a few days; a record that your account existed, and its subscription status, may be retained where we need it for billing or fraud prevention. Deleting the app removes the copy on your device. Data you wrote to Apple Health is managed in the Health app and is not deleted by us.
Your backup is kept until you delete your account or replace it with a newer backup. Daily AI usage counts expire automatically within a few days.
One4 is not directed to children under 13, and we do not knowingly collect data from them.
We may update this policy; the date above will change when we do. Continued use after an update means you accept the revised policy.
Questions, or want a copy of your data? Contact [email protected].