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Fast Slow - Fasting Tracker

Fast Slow - Fasting Tracker

Intermittent 16:8 Free Timer

22 ratings
3 reviews
🔧 Utilities
💪 Health & Fitness
Free
In-App Purchases

Details

  • Released
  • Updated
  • August 22, 2025
  • June 15, 2026

Features

Developer

Zan Cerne
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🧾$1.99 - $12.99
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About

Understand your body's metabolic changes during fasting with a visual timeline. This free app guides you through different fasting zones, from digestion to deep ketosis, and offers customizable schedules and smart notifications. It provides stats, streaks, and widgets for easy progress tracking.

✓Fasting timer with visual timeline
✓6 customizable fasting schedules
✓5 distinct fasting zones explained
✓Smart notifications for fasting windows
✓Stats, streaks, and trends tracking
✓Home and Lock Screen widgets
✓Siri Shortcuts integration
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What's New in Fast Slow

2.2.1

June 15, 2026

Fixes an issue where fasting history could appear missing and new fasts couldn't be started after updating. Your data is safe and restored automatically.

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Subscription plans

Legacy - Yearly

Legacy - Yearly subscription for Fast Slow.

$12.991 Year
3 Days trial
Price Updates
May 9, 2026→$12.99
December 7, 2025→$12.99
October 26, 2025→$24.99
How to cancel Fast Slow subscription ⁉️
4

In-App Purchases

$9.99

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Support the development of Fast Slow!

Events

Read more about Seasonal Fasting Reset
Event EndedLive Event

Seasonal Fasting Reset

Start fresh with guided fasting

Sep 7, 2025 — Sep 29, 2025

Read More

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User reviews

Most RecentHighest RatedLowest Rated

Easy fasting app

I found this app when I wanted to start tracking my intermittent fasting journey. I didn’t have to buy a subscription and it was so easy to track my fasting times and adjust them if necessary. It also keeps a history which I find very useful. I love this app I would definitely recommend it!
MiniGirl88MiniGirl88

Response from developer

That's amazing! Thank you so much for the kind words.

Very good

Been using this for 66 days after my old fast app stopped working. I love how nothing cost money and it shows the different zones my body is in during my fast. Overall great! I recommended to others and they now use it also.
drizzles15drizzles15

Response from developer

Thank you so much! As an indie developer, I really appreciate it! I'm glad you find it useful.

Great fasting app

Simple but has everything I need to fast. The little motivational blurb helps me everyday push through.
AprilhytdbjnAprilhytdbjn

Response from developer

Thank you so much! This means a lot. I'm really glad you're enjoying the app.

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FAQ

Does Fast Slow have ads?

No, Fast Slow is completely free with no ads. The developer has stated it is ad-free forever, with every feature included without paywalls or trackers.

What fasting schedules does Fast Slow offer?

Fast Slow provides 6 fasting schedules: 12:12, 14:10, 16:8, 18:6, 20:4, and OMAD (one meal a day). Users can pick a schedule and adjust it as needed.

How does Fast Slow explain fasting zones?

Fast Slow walks users through 5 fasting zones: Anabolic (0-4h), Catabolic (4-8h), Fat Burning (8-12h), Ketosis (12-16h), and Deep Ketosis (16h+). Each zone is explained with its scientific basis.

Can I track my progress with Fast Slow?

Yes, Fast Slow offers stats and streaks, including total fasts, average duration, personal records, weekly trends, and a monthly fasting calendar. This helps users monitor their progress and celebrate small wins.

What devices is Fast Slow available on?

Based on the provided data, Fast Slow is currently supported on iPhone. It also features iCloud sync for seamless data across Apple devices.

How often is Fast Slow updated?

The app was last updated on April 26, 2026, indicating ongoing development and support. The latest version is 2.1.2.

Is Fast Slow suitable for beginners?

Yes, Fast Slow is designed for real life and works for both new and experienced fasters. It offers schedules like 12:12, which is suitable for beginners, and guides users through the process.

Can I export my data from Fast Slow?

Yes, Fast Slow allows users to export their fasting history as JSON data. Users also have the option to delete all their data with a single tap, emphasizing data ownership.