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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.

Download on the App Store

Free to start. Pro from $3.33/month. Lifetime option available.

Every other fasting app does the same thing.

Start a timer.
Stop a timer.
Pay every year to do it again.

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.

Hour 14 · Mood: Hungry

"I'm starving. All I can think about is food. I don't know if I can make it to 18 hours."

Hunger tends to come in waves, and a wave often passes in 15 to 20 minutes. A glass of water or a short walk can help you sit through it. If it doesn't pass, ending the fast is a fine choice too.
Hour 36 · Mood: Low

"I feel flat. Not hungry really, just... empty. Like what's the point of pushing further?"

Thirty-six hours is a long fast, and what you are feeling counts. Drink water with electrolytes and rest. On a fast this long, feeling unwell is a good reason to stop and eat. Every hour you did still counts.
Hour 22 · Thinking about stopping

"I'm standing in the kitchen. I just need one bite. One won't hurt."

Your own words: "I want to see that I can." Cravings often pass in a few minutes. Try a glass of water and a different room for ten. If you still want to eat after that, eat. Twenty-two hours is a real fast either way.

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.

0 - 4 Hours

Fed state

Your body is digesting your last meal. Blood sugar rises and then settles.

4 - 8 Hours

Early fasting

Digestion is finishing and insulin is coming down. The first mild hunger often arrives at your usual mealtimes.

8 - 12 Hours

Stored energy

Your body is drawing on stored glycogen. Hunger tends to come in waves here, and pass.

12 - 18 Hours

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.

18 - 24 Hours

Running on fat

Fat is likely your main fuel by now. Keep drinking water, and keep warm.

24 - 36 Hours

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.

36 - 48 Hours

Extended fast

Well into an extended fast. Go gently, keep up water and electrolytes, and eat if you feel unwell.

48 - 72+ Hours

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.

Download on the App Store

Stay with it.

Available now — free to start
Download on the App Store