
Fast: Intermittent Fast Timer
Adaptive fasting · 16:8 + AI
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$2.99 Free
In-App Purchases
Lowest price: Free 3 months ago (-100%)
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Price history
About
Track 16:8 fasting with an AI coach that actually adjusts to your hunger, sleep, and energy — not just a timer.
4-state color coding: eating, fasting, autophagy, ketosis. Free basic 16:8. Pro unlocks OMAD / 18:6 / 20:4 / 5:2 + the AI coach that adapts daily.
THE AI COACH
The "AI" is not an LLM call. It's a deterministic on-device engine that reads your sleep, HRV, weight trend, and activity from Apple Health, picks the right context from tens of billions of possible coach lines, and quietly suggests a gentler window after a poor night or a small push when recovery is strong. There is no server. Your fasting data never leaves your phone.
WHAT'S NEW IN v1.0.1
• Redesigned "precision watch" dark theme — full-bleed circular timer with 4 phase colors
• Streak ribbon and phase chip pinned to the top of Today
• Faster monospace countdown, sharper typography
• New app icon — dark dial + amber hour ticks
• Refreshed onboarding copy + paywall positioning
WHAT'S IN
• All five protocols: 16:8 (free), 18:6, 20:4, OMAD, and 5:2
• On-device coach reading sleep, HRV, body mass, and active energy from Apple Health
• Phase tracking: Clean Slate → Fat Burn → Autophagy → Ketosis, with gentle local notifications when you cross each one
• Break-fast guidance — one hour before your window opens, a short card calibrated to your goal
• Weekly adherence + weight-trend report
• Water + electrolyte log
WHAT WE PROMISE TO SKIP
• No streak-shaming notifications
• No "you broke your fast" guilt pings
• No before/after body photos in marketing or in-app
• No supplement / electrolyte-powder affiliate links
• No social comparison ("your friends fasted longer")
• No selling, sharing, or trading your data — there is literally no server to sell it from
PRO (LIFETIME)
$99 one-time. Unlocks all five protocols and the daily HealthKit-driven adaptation. The free tier is the real 16:8 timer with the coach line; you can use Fast forever without paying.
PRIVACY
The coach engine ships entirely on your device. The free tier needs no login, no email, no analytics. HealthKit reads happen in-process and are never written to disk verbatim — only the bucket category is used. Anonymous receipts validate Pro. That's it.
NOT MEDICAL ADVICE
Fast is a wellness companion. If you have a health condition, are pregnant or nursing, are managing diabetes or an eating disorder, or take medication that interacts with fasting, talk to a clinician before changing your eating pattern.
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What's New in Fast
1.0.4
June 12, 2026
ASO refresh: improved discoverability with sharper subtitle, keywords, and promotional text.
1
In-App Purchases
$99.00
Lifetime
All protocols + on-device coach. One-time.




