Features designed for real progress
Fastive combines a precision fasting timer with metabolic education, daily logging, and optional AI meal analysis. The app works offline, supports nine languages, and syncs with Apple Health on iOS and Health Connect on Android.
Intermittent fasting timer
- Start / end / cancel fasts
- Retroactive start (forgot to tap start — up to 7 days back)
- Eating window vs fasting window countdown
- One active fast at a time
- Completed fasts saved to history and stats
Metabolic phase timeline
| Phase | Starts at | What happens (educational) |
|---|---|---|
| Fed State | 0h | Digesting food, using glucose |
| Fat Burning | 12h+ | Insulin drops, fat mobilization begins |
| Ketosis | 14h+ | Ketone production for fuel |
| Autophagy | 16h+ | Cellular cleanup and recycling |
| Deep Autophagy | 24h+ | Peak cellular renewal phase |
Timeline is educational. Individual metabolism varies.
AI meal photo analysis
- Take or upload a meal photo
- AI returns estimated calories, protein, carbs, fat
- Fast-breaking indicator and short feedback
- 1 AI scan per UTC day
- Manual meal logging always available without AI
Water tracker
- Custom daily goal (default 2000 ml)
- Quick-add amounts
- Daily progress ring
- Water reminder notifications (optional)
Weight tracking
- Manual entry or Health import
- History list and trend over time
- Supports kg / lb
History, streaks & badges
- Calendar of completed fasts
- Current streak on home screen
- Achievement badges (Premium): first fast, 7-day streak, 100 hours, ketosis hunter, hydration pro, and more
- Activity heat map (Premium): visual consistency grid
Notifications & Live Activity
- Fast start reminder (30 min before by default)
- Fast end notification
- Phase milestone alerts
- Water reminders (interval-based)
- Idle movement nudge during long fasts
- iOS Live Activity: lock screen + Dynamic Island timer
Apple Health & Health Connect
- Opt-in only — you control permissions
- Read: body weight, step count
- Write: completed fasting sessions
- Disable anytime in Settings
Learn more in our guide: How to track fasting with Apple Health
Privacy & accounts
- Guest mode on first launch (no email required)
- Optional email link for cross-device sync
- Delete registered account in Settings
- Privacy Policy: transparent data practices