What happens on your device
All calculations run in your browser: fasting windows and schedules, the timer, the reverse diet calorie ramp, and the body-measurement estimates (ABSI and visceral fat). Everything you enter and choose to save stays in your browser's local storage (localStorage and IndexedDB): fasting sessions, your saved reverse diet plan settings, and any body measurements you save for trend tracking, including age, sex, height, weight, waist, and thigh values. No account exists, and none of this is transmitted to us or anyone else. We consider body measurements sensitive, which is exactly why the tools are built so we never receive them.
What leaves your device
- Standard web requests: your browser fetches this site's pages, styles, scripts, and the Archivo font from Google Fonts. Font requests are subject to Google's privacy policy.
- Share links you create contain only a fast duration and a clock time: no history, no identity. Sending a link is your choice.
- Calendar (.ics) files and JSON/CSV exports, including body-measurement history exports, are generated locally and saved to your device; we never see them.
- Standard page-analytics requests to Google Analytics (see the analytics section below). These carry page views and technical metadata, never your tool inputs.
Analytics and cookies
This site uses Google Analytics 4 to understand aggregate usage: which pages are visited, roughly where visitors come from, and how the site performs. Google Analytics sets cookies and collects standard technical data (such as browser type, approximate location derived from IP, and pages viewed) under Google's privacy policy. What analytics never receives from us: anything you type into the tools. Your meal times, fasting sessions, calorie plans, and body measurements are processed and stored only on your device and are not sent to Google or anyone else. You can block analytics with any standard content blocker or Google's own opt-out browser add-on, and every calculator works exactly the same with it blocked.
Advertising
This site is free to use and carries no subscription, so advertising is how it pays for itself. We are applying to Google AdSense, and no advertising is running on the site yet. This section describes what will happen when it is, so you can read it before rather than after.
Google and its partners use cookies to serve ads based on your prior visits to this site and other sites. Google's use of advertising cookies lets it and its partners serve ads based on that activity. You can opt out of personalised advertising at Google Ads Settings, and you can opt out of a wider set of vendors at aboutads.info. Blocking ads with an extension also works, and every calculator behaves identically with ads blocked.
One thing does not change when ads arrive. Advertisers never receive anything you type into the tools on this site, because those values never leave your browser to begin with. Your meal times, fasting history, calorie plans and body measurements are computed and stored on your own device, and there is no server holding them for anyone to buy, share or leak. Ads are served alongside the page; they are not fed by it.
Deleting your data
Every store has its own delete control: the history page removes fasting sessions, and the ABSI and visceral fat calculators each have "Delete all" buttons for their saved measurements. Clearing your browser's site data removes everything at once. Because we hold nothing, there is nothing for us to delete on any server.
Contact
Questions about this policy can be sent to the site operator. This page was last updated in August 2026 and will be revised if any practice described here changes.