Privacy Policy

We use the information described above only to run Zero Fast for you:

• Core features: your account, the fasting timer, logs, history, streaks, statistics and reminders.
• Keeping your data with your account: storing what §1.1 lists in Firebase.
• Personal estimates: fasting stages, the AI weekly plan and predictive insights. These are worked out on your iPhone from your own logs and send nothing anywhere.
• Challenges: showing you and the other people in a challenge its leaderboard and cheers (§6).
• Premium AI features: the monthly summary insight and accountability reminders (§5).
• Subscriptions: checking whether your account has Premium, through RevenueCat and the App Store.
• Support: answering you when you write to us.
• Protecting the service and meeting the law: for example, enforcing AI usage limits, and responding to lawful requests.

We do not use your information for advertising, we do not run analytics on how you use the app, and Zero Fast does not send marketing email.

• No selling or renting. We do not sell or rent your personal information, including your health information, to anyone.
• No advertising use. Your information is not shared with anyone for marketing or advertising.
• Service providers. Google Firebase, Anthropic, RevenueCat and Apple handle information to run Zero Fast for us. §10 lists what each one receives.
• Other Zero Fast users. Only the challenge information described in §6.
• Legal requirements. We may disclose information if the law requires it, or where it is needed to protect the rights or safety of our users or others.
• Business transfers. If our business or Zero Fast is sold or merged, your information may pass to the new owner, who would have to handle it as this policy describes.
• What you share yourself. If you share a progress photo or export a file through the iOS share sheet, it goes wherever you send it.

Connecting Apple Health is optional. iOS asks your permission for each type of data, and you can change your choices at any time in the Health app or in your iPhone’s privacy settings.

• How reads are used. On your iPhone: your current weight and weight trend, your date of birth and your height on the You tab, and your steps and active energy on the timer and in your fast summaries. Zero Fast asks to read biological sex but does not currently use it.
• Background updates. Zero Fast asks Apple Health to tell it about new steps and active energy in the background, so the figures are current.
• What is written. The weights you log, the height you set in Settings and the water you log, so your other health apps can use them.
• No fasting sessions. Zero Fast does not read or write fasting sessions in Apple Health.

What happens to Apple Health data. Values Zero Fast reads from Apple Health stay on your iPhone. They are not uploaded to our servers, not sent to RevenueCat or to Anthropic, not used for advertising or marketing, and never sold.

One overlap to know about. A weight, height or water amount you enter in Zero Fast is saved to your account on Firebase (§1.1) and, if you allowed it, to Apple Health as well. The copy in your account comes from what you typed into Zero Fast, not from Apple Health.

Zero Fast works without Apple Health, but the current weight and weight trend on the You tab come from Apple Health, so they stay empty without it. Data Zero Fast has written to Apple Health belongs to the Health app: deleting your Zero Fast account does not remove it, and you can delete it in the Health app.

Two Premium features use an AI model that runs off your device: the written insight on your monthly summary, and accountability reminders. Both are written by Claude, a model made by Anthropic. The app sends the request to Firebase Cloud Functions that we run, and our function sends it on to Anthropic’s API and returns the reply.

When you create or join a challenge, it stores your name, your progress, your score and when you joined, and the other people in the challenge see them on its leaderboard. If you created it, your name is shown as its creator. The name is the one in your profile, never your email address; if you have not given a name, a placeholder such as “User 4f2a” is shown. The challenge also holds each participant’s account id.

New challenges are set to “Anyone can join” by default, which lists them for every Zero Fast user. You can switch that off when you create a challenge, so people join with its invite code instead. Even then, treat what is in a challenge as visible to other Zero Fast users, not as private.

A cheer you send stores your name and account id, and is shown to the people in that challenge.

There is currently no button in the app to leave a challenge, delete one you created, or remove a cheer. Write to hey@appe-latte.ca and we will do it for you. Deleting your account does not remove them on its own (§12).

• In transit. The app talks to Firebase, RevenueCat and Apple over encrypted connections (TLS).
• At our providers. Google Firebase encrypts the data it stores by default.
• Access rules. Our Firebase security rules let each signed-in account read and change only its own profile, logs, journal entries and photos. Challenges are the exception described in §6.
• Sign-in. Your password goes straight to Firebase Authentication and is not stored by the app. Deleting your account asks for your password again first.
• Server secrets. The key that lets our functions reach Anthropic is held on our server as a secret and is never in the app.
• On your iPhone. Zero Fast’s local data sits in the app’s own storage, which other apps cannot read. Keep your iPhone locked with a passcode.

No method of transmission or storage is completely secure, and we cannot guarantee absolute security. If we have a breach that creates a real risk of significant harm to you, we will tell you and the privacy regulator, as the law requires.

Zero Fast is not intended for children under 13, and we do not knowingly collect personal information from them. Zero Fast does not currently check age when you sign up. Fasting may not be appropriate for minors, and anyone thinking about fasting should talk to a healthcare professional first. If we learn that an account belongs to a child under 13, we will delete it and its data. If you believe a child is using Zero Fast, write to hey@appe-latte.ca.

In the app:

• Change it. Edit your name, height, date of birth and starting and target weights in Settings, and log a new weight to update your current weight. For anything else, write to us.
• Export it. Settings → Export Your Data creates CSV files of your fasts, weight entries, water logs, journal entries (including your notes) and progress-photo records (date, weights and note, not the images), or a PDF report of your fasts and weights, and hands them to the share sheet. It is free for everyone. It does not include the photo images, your profile or your challenges; ask us for a copy of those.
• Delete entries. You can delete individual fasts, water entries and journal entries in the app. There is currently no button to delete a single progress photo; write to us and we will remove it from your account.
• Clear this device. Settings → Clear data on this device removes the fasts, weight entries and water logs stored on this iPhone, and clears the weights on your profile on this iPhone. It keeps your account, and it does not delete the copies stored in your account on Firebase. To remove those, delete your account or write to us.
• Delete your account. Settings → Delete Account. §12 explains exactly what it removes and what it leaves behind.
• Turn things off. Apple Health, camera, photo library and notification access are iOS permissions you can withdraw at any time in Settings. Zero Fast keeps working without them, with the features that need them switched off.

How your consent works. By creating an account and using these features, you agree to us storing what §1.1 lists in your account. Apple Health, camera, photo library and notifications are iOS permissions you grant and can take back. Creating or joining a challenge is your consent to show your name, progress and score to other users as §6 describes. With Premium, the AI features in §5 run as described there. You can withdraw your consent by turning a permission off, by writing to us, or by deleting your account; some features stop working without it.

Under Canadian privacy law (the Personal Information Protection and Electronic Documents Act, and Alberta’s Personal Information Protection Act) you have the right to ask what personal information we hold about you, to ask for a copy, to ask us to correct it, to ask us to delete it and to withdraw your consent. Write to hey@appe-latte.ca and we will answer within 30 days. If you are not satisfied with our answer, you can complain to the Office of the Privacy Commissioner of Canada (priv.gc.ca) or to the Office of the Information and Privacy Commissioner of Alberta (oipc.ab.ca).

If you live outside Canada, you may have similar rights under your own law, and you can make the same requests to us.

We use these providers to run Zero Fast on our behalf:

Their privacy policies: Firebase, Anthropic, RevenueCat and Apple.

Settings also links to our Instagram and Facebook pages and to Zero Fast on the App Store. Opening them takes you to those services, under their own policies.

Our providers (Google, Anthropic, RevenueCat and Apple) are based in the United States, and your information may be stored and processed in the United States and in other countries where they operate, including wherever Google Firebase keeps your account data. While it is outside Canada, it may be accessible to the courts, law enforcement and national-security authorities of those countries under their laws. We want you to know that before you create an account.

Zero Fast is designed for informational and tracking purposes only. It is not intended to diagnose, treat, cure, or prevent any disease or medical condition. Always consult with a qualified healthcare professional before beginning any fasting program or making changes to your diet or lifestyle. The App does not provide medical advice.

If we change this policy, we will post the new version on this page and update the date at the top. If a change is material, such as new kinds of information, a new provider or a new purpose, we will also tell you by email at the address on your account before the change takes effect. Small corrections and clarifications may simply be updated here.

Appè Latte Limited, operating as Appè Latte, Calgary, Alberta, Canada.

Privacy questions, data requests and complaints: hey@appe-latte.ca. That address reaches the person at Appè Latte Limited who is accountable for privacy and for this policy. We answer within 30 days.

October 14, 2026: rewritten to match the app as it works today. The main changes from the version dated June 1, 2024:

• Cloud storage disclosed. The old policy said all health data stays on your device. In fact your profile (including height, weights, date of birth and gender), fasts, water and weight logs, journal entries and progress photos are stored in your account on Google Firebase (§1.1). Values read from Apple Health do stay on your iPhone.
• Apple Health corrected. Zero Fast never reads or writes fasting sessions in Apple Health. It reads weight, height, water, date of birth, biological sex, active energy and steps, and writes weight, height and water (§4).
• AI processing added. Two Premium features send a short summary of your logs to Anthropic’s Claude through our Firebase Cloud Functions (§5).
• Journal, progress photos and challenges added, including what other Zero Fast users can see in a challenge (§1.1, §6).
• Processors named. Google Firebase, Anthropic, RevenueCat and Apple, with what each receives (§10).
• Analytics claims removed. The old policy described usage analytics. Zero Fast has no analytics, advertising or tracking code (§1.3); the device details RevenueCat receives to manage subscriptions are listed in §10.
• Deletion described accurately. The items in-app deletion leaves behind are now listed, with how to have them removed (§12). The old “within 90 days” statement is withdrawn.
• Promises we could not keep removed: “regular security audits”, a blanket encryption claim, and in-app notices or consent prompts for policy changes. Material changes are now announced by email (§14).
• Your rights under Canadian privacy law, and how to complain to a regulator, added (§9). Our contact address is now hey@appe-latte.ca.