# Fast: Intermittent Fast Timer — Adaptive fasting · 16:8 + AI

> Adaptive fasting · 16:8 + AI (iPhone/iPad app by jiahao zhang.)

- Source: https://appshunter.io/ios/app/fast-intermittent-fast-timer/id6766843905 (this page in markdown: same URL + `.md`)
- Developer: [jiahao zhang](https://appshunter.io/developer/1895708572)
- Category: Health & Fitness, Lifestyle
- Price: Free with in-app purchases (on sale, was $2.99)
- Age rating: 4+
- Requires: iOS 17.0 · 1 MB
- Languages: English
- Released: 2026-05-06
- Data updated: 2026-06-25
- User reviews in markdown: https://appshunter.io/ios/app/fast-intermittent-fast-timer/id6766843905/reviews.md

## What is Fast?

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.

## Pricing and in-app purchases

Base price: Free.

**One-time purchases**

| Purchase | Price | Type |
| --- | --- | --- |
| Lifetime | $99.00 | one-time |



## Version history (last 3 releases)

### 1.0.4 — 2026-06-12

ASO refresh: improved discoverability with sharper subtitle, keywords, and promotional text.

### 1.0.1 — 2026-05-22

v1.0.1 — Precision-watch dark refresh

• Brand-new dark "precision watch" theme. Deep slate canvas, amber accents, monospace numerals.
• Full-bleed circular timer with 4 phase colors: clean-slate, fat-burn, autophagy, ketosis.
• Streak ribbon + phase chip pinned to the top of Today.
• Redesigned app icon — dark dial + amber hour ticks.
• Same on-device AI coach. Same privacy. Same one-time Lifetime IAP.

### 1.0.0 — 2026-05-07

No release notes.

## More apps by jiahao zhang

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- [Flicker · letters at night](https://appshunter.io/ios/app/flicker-letters-at-night/id6765566805)
- [Phase: Perimenopause & HRT](https://appshunter.io/ios/app/phase-perimenopause-and-hrt/id6765830533)
- [Rehearsal: Interview Prep](https://appshunter.io/ios/app/rehearsal-interview-prep/id6765836387)
- [Cleanup AI: Remove Anyone](https://appshunter.io/ios/app/cleanup-ai-remove-anyone/id6766029237)

All apps by jiahao zhang: https://appshunter.io/developer/1895708572

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-06-25.*