Your fasting app should know why you're fasting.
StayFasted keeps you company through every hour of a fast, with on-device AI that responds to how you feel and why you started. No account. Your fasting data stays on your phone.
Free to start. Pro from $3.33/month. Lifetime option available.
Every other fasting app does the same thing.
You deserve more than a countdown clock.
A coach that knows what
hour 36 feels like.
On-device AI that responds to what you wrote, how you feel and why you started. It never pushes you to carry on, and it is not medical advice.
"I'm starving. All I can think about is food. I don't know if I can make it to 18 hours."
"I feel flat. Not hungry really, just... empty. Like what's the point of pushing further?"
"I'm standing in the kitchen. I just need one bite. One won't hurt."
See it in action.
Real screenshots from StayFasted. Every screen designed to keep you in your fast.
Know what to expect,
hour by hour.
StayFasted describes eight parts of a fast: what is generally understood about each, what people often feel, and what tends to help. Timing differs from person to person, and none of it is medical advice.
Fed state
Your body is digesting your last meal. Blood sugar rises and then settles.
Early fasting
Digestion is finishing and insulin is coming down. The first mild hunger often arrives at your usual mealtimes.
Stored energy
Your body is drawing on stored glycogen. Hunger tends to come in waves here, and pass.
Shifting to fat
Many people start using more fat for fuel around now, and the liver begins to make ketones. Some notice clearer focus, others a dip.
Running on fat
Fat is likely your main fuel by now. Keep drinking water, and keep warm.
Day two
A longer fast. Researchers study cellular recycling (autophagy) in fasts of this length, mostly in animals so far. Electrolytes start to matter more.
Extended fast
Well into an extended fast. Go gently, keep up water and electrolytes, and eat if you feel unwell.
Long fast
A long fast. Plan a gentle first meal, and check with your doctor before fasting this long, especially if you take medication.
Built for people who
actually fast.
Features you won't find in any other fasting app. Because we built the app we wished existed.
Schedule Next Fast & Rhythm Planner
Plan your fasting rhythm weeks ahead. Set repeating schedules — 16:8 Mon-Fri, 24h on Sundays, 48h once a month. Your calendar, your rhythm, your life.
28-Day Adherence Grid
See your fasting consistency at a glance. Green for completed, yellow for partial, empty for missed. Patterns emerge. Streaks motivate. Accountability becomes visual.
Refeed Guide
Breaking a fast matters as much as the fast itself. Get personalized refeed recommendations based on your fast duration — what to eat, what to avoid, and when.
Live Activities & Dynamic Island
Your fasting timer lives on your lock screen and Dynamic Island. See elapsed time, current stage, and remaining time without ever opening the app.
Apple Watch App
Start and stop fasts, log water, and check in with your mood — all from your wrist. Full timer with stage tracking and haptic feedback.
Your fasting data stays
on your phone.
No account and no StayFasted server. Your fasts, check-ins, photos and AI replies are stored on your iPhone. Three optional features use the internet, only if you turn them on: weather sends an approximate location to Apple Weather, scanning a drink looks its barcode up at Open Food Facts, and Apple Music playlists come from Apple.
On-Device AI
Replies to your check-ins are generated on your iPhone. What you write is not sent to a server.
No Account Required
No email, no login, no sign-up wall. Download the app and start.
Apple Health Integration
Optional. Reads weight, steps, sleep, resting heart rate and active energy, and writes weight, water and mindful minutes. You choose what to share in the Health app.
Your next fast doesn't
have to be alone.
Whether it's your first 16-hour fast or your tenth 72-hour fast — StayFasted is the partner that stays with you through every hard moment.
Stay with it.