Privacy policy

Last updated: 30 September 2026

LeanFast is built to work privately. You can use it fully without an account, and most of your data never leaves your iPhone. This page explains what we collect, why, and the choices you have.

Data stored on your device

Your profile answers (age, sex, height, weight, goal, activity, wake and sleep times, safety answers), your fasting schedule and history, weight, water and food logs are stored on your iPhone. Progress photos are only ever stored on your device and are never uploaded.

Optional account and sync

If you create an account with email, Google or Apple, we store your email address and sync your profile, schedule, fasts, weight, water and food logs so you can restore them on another device. The data is hosted by our processor Supabase in the European Union. Row-level security means each account can read only its own rows. We don't sync progress photos or the photos you scan.

Prism Lens (food scanner)

Text recognition, barcode detection, meal recognition and advice generation all run on your device using Apple's frameworks, including Apple Intelligence where it is available. Images are not sent to us. When you scan a barcode that isn't in the built-in database, only the barcode number is sent to Open Food Facts to look up the product.

Purchases

Subscriptions are processed by Apple. We never see your payment details. We only receive whether your LeanFast Prism subscription is active.

What we don't do

• No advertising, and no third-party analytics or tracking SDKs.
• We never sell or rent your data.
• We don't use your data to train AI models.

Health information

Weight, eating habits and the safety questions (such as pregnancy) are health-related data. We process them only to provide the app, based on your explicit consent, which you give by entering them. You can withdraw that consent at any time by deleting the data.

Your rights

You can export your data (Settings › Export my data) and delete it (Settings › Delete all data). You can also delete your account and all synced data (Settings › Delete account), which takes effect immediately. If you are in the EU, UK or a similar jurisdiction, you have the right to access, correct, delete and port your data, and to complain to your data-protection authority.

Retention

Synced data is kept until you delete it or delete your account. Backups held by our processor roll off within their standard backup window.

Children

LeanFast is not intended for anyone under 18, and the app doesn't create fasting plans for them.

Contact

If you have questions or requests, email support@chebbi.org.