FastTrack48

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Everyone
5+
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Content rating
Everyone
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About this app

Free and fully open source. No ads, no in-app purchases, no Internet permissions.

FastTrack48 tells you what is happening to your body while you fast, and you'll learn more
about each phase as you progress in your fast

Features



During a fast
• Radial dial showing elapsed time and the phase you are currently in.
• Ten stages from the last meal to 72 hours+: blood sugar rise, blood sugar fall, blood sugar stabilises, gluconeogenesis, fat burning, ketosis, autophagy, growth hormone surge, insulin sensitivity, immune cell regeneration.
• At each stage you get an explanation of what is happening in your body, with references.
• Tappable bubbles for each phase — glucose burning, fat burning, ketosis, autophagy, optimal autophagy.
• Phases can appear only once you reach them, or be shown from the start; each is individually toggleable.
• Ongoing notification display elapsed time and current stage.
• Notifications when you enter a new stage.
• Home screen widget.
• Launcher shortcuts: start a fast, start now, end fast.
• Share your current or finished fast as text.
• Six-screen intro explaining the app on first launch.

Fasting history
• Every fast recorded with start time, total length, hours in ketosis and hours in autophagy.
• Add text notes for any entry.
• List and calendar views of your previous fasts.
• Tap any past day in the calendar to add a fast for it.
• Manual entry: set start date and time plus a duration, or set an end time and let the app calculate.
• Edit or delete any entry, including backdating a start you forgot to log.
• Clear the entire fasting history.

Import and export
• Export as CSV (Excel-compatible).
• Export as iCalendar (.ics) to load your fasts into any calendar app.
• Export as ActivityStreams 2.0 (JSON-LD).
• Import a previous export back into the app.
• Import EasyFast .zip backups; overlapping entries are skipped to avoid duplicates.

Body profile
• Age, sex, height and weight, in metric or imperial.
• BMI with its category, and BMR in kcal per day.

Appearance and settings
• Light, dark, or follow the system theme.
• Animated or plain background.
• Configurable date and time format.
• Metric / imperial units.
• Toggles for the ongoing notification and for stage alerts.

Localization


• Free and open source under the MIT licence, no strings attached
• Material design throughout, with light, dark and system themes and a configurable date and time format
• Available in nine languages

FastTrack48 is not a medical app and does not provide medical advice. The stage timings come from a rule-of-thumb model informed by published research and real-world testing, and they are an approximation: what stage you are actually in depends on your metabolism, your last meal, your activity and much else. Talk to a doctor before fasting, especially if you are pregnant, are taking medication, or have a medical condition.


Attribution



FastTrack48 is a modified derivative work of FastTrack, created by Adam Brown (@Wavesonics) and published by Dark Rock Studios. The original software is Copyright © 2020 Adam Brown and is made available under the MIT License, which continues to govern the original portions of this app. The full licence text is reproduced inside the app under About → Acknowledgements.

Every modification, addition and design change in FastTrack48 is the sole work and responsibility of this project. Adam Brown and Dark Rock Studios do not maintain, endorse, sponsor or support FastTrack48 and bear no responsibility for it. Please send all questions and support requests about FastTrack48 to https://github.com/fasttrack42/FastTrack48/issues and never to the original project.

The names "FastTrack", "Dark Rock Studios" and "Wavesonics" are used solely to identify the origin of the source code.
Track what your body is doing while fasting
Updated on
Sep 2, 2026

Data safety

Safety starts with understanding how developers collect and share your data. Data privacy and security practices may vary based on your use, region, and age. The developer provided this information and may update it over time.
  • No data shared with third parties
    Learn more about how developers declare sharing
  • No data collected
    Learn more about how developers declare collection

What’s new

- import your fasting history by tapping from a file manager a .csv .json .ics file created by FastTrack48 or a .zip backup from EasyFast
Content rating
Everyone
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App support

About the developer
viorel lupu
slavery.two.point.zero@gmail.com
C. de Homer, 26, bajo 3 08023 Barcelona Spain