Fast Slow vs Intermittent
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Fast Slow
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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See what happens inside your body as you fast. Fast Slow walks you through 5 fasting zones, from digestion through fat burning to deep ketosis, so you understand what every hour of your fast is doing. 100% free. Every feature. No ads. No paywalls. No trackers. Free forever. WHAT MAKES FAST SLOW DIFFERENT Most fasting apps just count down a timer. Fast Slow shows you what's actually happening in your body at each stage: - Anabolic (0-4h): Digesting and storing nutrients - Catabolic (4-8h): Tapping into energy reserves - Fat Burning (8-12h): The metabolic switch - Ketosis (12-16h): Ketones and cellular cleanup - Deep Ketosis (16h+): Deep cellular renewal Tap any zone to learn more about the science behind it. 100% FREE. EVERY FEATURE INCLUDED. No premium tier. No trial that expires. No paywall gates. Every feature in Fast Slow is yours from day one: - All 6 fasting schedules - All stats, streaks, and trends - All widgets (Home Screen and Lock Screen) - All notifications - Siri Shortcuts - iCloud sync - Data export Everything free. No catches. FEATURES Fasting Timer One tap to start. One tap to stop. A visual timeline shows where you are, what zone you're in, and what comes next. 6 Fasting Schedules 12:12 for beginners, 14:10, 16:8 (the most popular), 18:6, 20:4, and OMAD (one meal a day) for experienced fasters. Visual Timeline Color-coded timeline of your fasting and eating windows. Plan meals, training, and recovery at a glance. Smart Notifications 7 notification types: goal reached, halfway there, one hour left, eating window alerts, and a custom last meal reminder. Nudges, not nags. Stats & Streaks Total fasts, average duration, personal records, weekly trends, and a monthly fasting calendar. Small wins add up. Widgets Home Screen and Lock Screen widgets with progress rings, timelines, and live timers. Check your fast without opening the app. Siri Shortcuts "Hey Siri, start my fast." Start, stop, and check your fasting status hands-free. AI-Powered Greetings On supported devices, Apple Intelligence creates personalized messages based on your fasting progress, streak, and time of day. iCloud Sync Your fasting data syncs automatically across all your devices. Data You Own Export your fasting history as JSON. Delete everything with one tap. Your data, your choice. DESIGNED FOR REAL LIFE Pick a schedule, adjust as needed, and let Fast Slow handle the timing. New to fasting or already have a routine, it works either way. Structure when you want it, out of the way when you don't. Built by one developer who fasts every day. No corporate agenda. No growth hacking. A well-made tool that respects your time and your data. RESPONSIBLE APPROACH Intermittent fasting can support weight management, energy, and focus, but results vary. Fast Slow provides tools and information, not medical advice. If you have health conditions, are pregnant, or have a history of eating disorders, please talk to a healthcare professional before starting.
Intermittent
Easily track your intermittent fasting with a visual timeline and preset or custom plans. Integrate with Apple Health for a holistic view of your wellness. Stay updated with widgets and Apple Watch support.
- Fasting timer
- Visual stage timeline
- Preset and custom plans
- Apple Health integration
- Apple Watch app
- Widgets and Live Activities
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100% FREE — NO SUBSCRIPTION, NO PAYWALL, NO IN-APP PURCHASES. BetterFasting is a simple, powerful intermittent fasting timer and tracker for your daily routine. Pick a plan, start your fast, and watch your progress build day after day. Every feature is unlocked from the very first tap. The app is supported by ads, so the tools stay open and free for everyone. POPULAR FASTING PLANS, OR YOUR OWN Fast with 16:8, 18:6, 20:4, OMAD, 5:2, or build a custom fasting window that fits your life. Start, stop, and edit fasts whenever you need to, so the timer always matches your real day. KNOW EXACTLY WHERE YOU ARE Follow live fasting stages as your body moves through your fast, with a clear timer ring and progress at a glance. Set smart reminders so you never miss the start or end of a window. TRACK WHAT MATTERS Log water and mood through the day, record your weight over time, and build streaks and badges that keep you motivated. Review your full fasting history with simple charts that show your trends week over week. ALWAYS WITHIN REACH Add home screen and lock screen widgets, keep your timer front and center with Live Activities and the Dynamic Island, and check your fast right from your wrist with the Apple Watch app. Apple Health sync keeps your data connected, and iCloud sync keeps everything safe across your devices. FAST TOGETHER Add friends, join groups, take on challenges, and cheer each other on in the activity feed. Staying accountable is easier when you are not doing it alone. SPEAKS YOUR LANGUAGE Available in 45 languages, including full right-to-left support. WHY BETTERFASTING? - 100% free: no subscription, no paywall, no in-app purchases. - Every plan and tool unlocked from day one. - Clean, fast, and easy to use every single day. - Ad-supported so the core experience stays open to all. Many fasting apps hide basic tools behind a subscription. BetterFasting is different. Start free, track your routine, stay accountable with friends, and keep the habit going. Fasting is a personal wellness routine, not medical advice. If you have a medical condition, are pregnant, or are unsure whether fasting is right for you, talk to a qualified health professional before you begin. Download BetterFasting and start your first fast today.
Screenshots
Verdict
Fast Slow and Intermittent both sit at 5.0 stars, but that hides the real split: 100% of Fast Slow's written reviews are positive against 50% of Intermittent's. Fast Slow also leads on monetization model (free vs freemium). Intermittent's advantage is update cadence (every 4 days vs fortnightly) and device support (3 vs 1). On price, rating, ratings volume and ads there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. Fast Slow sells 4 in-app purchases, starting at $1.99 per 7 days and Intermittent sells 4 in-app purchases, starting at $4.99 per month. Whichever you choose, the download price is not the number that matters.
On the App Store both sit at effectively the same score — 5.0 for Fast Slow against 5.0 for Intermittent. Both are backed by a comparable volume of ratings — 22 and 9 respectively. Written reviews are what separate them: 100% of Fast Slow's written reviews are positive against 50% of Intermittent's.
Fast Slow ships an update fortnightly, Intermittent every 4 days. The most recent releases landed on September 13, 2026 and August 20, 2026 respectively.
| Parameter | Fast Slow | Intermittent |
|---|---|---|
| Price | Free | Free |
| Rating | 5.0 (22 ratings) | 5.0 (9 ratings) |
| Positive reviews | 100.0% of reviews — better | 50.0% of reviews |
| Number of ratings | 22 — better | 9 |
| Update frequency | Fortnightly | Every 4 days — better |
| Ads | No | No |
| In-app purchases | Yes | Yes |
| Monetization | Free — better | Freemium |
| Devices | iPhone | iPhone, iPad, Apple Watch — better |
| Requires iOS | 18.0 | 17.6 — better |
| Further details — not scored | ||
| Size | 19 MB | 33 MB |
| Age rating | 4+ | 12+ |
| Developer | Zan Cerne | BARBAROS SELIM BUYUKELCI |
Customer experience
Fast Slow
Intermittent
In-app purchases
Fast Slow
- Legacy$1.997 Days
- Legacy - Yearly3 Days trial$12.991 Year
- Buy Me a Coffee$2.99
- You're Amazing$9.99
Intermittent
- Monthly Premium3 Days trial$4.991 Month
- 3 Months Premium3 Days trial$9.993 Months
- 6 Months Premium3 Days trial$24.996 Months
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- Yearly Premium3 Days trial$34.991 Year





