ONE: Intermittent fasting App

Contains adsIn-app purchases
Content rating
Everyone
10+
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Content rating
Everyone
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About this app

ONE is the intermittent fasting app that keeps it simple: start a fast in one tap, watch your body move through each fasting stage, and build a streak that actually changes things. It's an intermittent fasting tracker and protein tracker in one, with no account needed and no clutter.

Whether you're new to intermittent fasting or already experienced, ONE helps you stay consistent. It gives you the habit without the homework.

CHOOSE YOUR FASTING PLAN
• 12:12, 14:10, 16:8, 18:6, 20:4 and OMAD (23:1)
• Flexi mode for open-ended fasts
• Every plan shows how hard it is, so you pick one you'll keep
• Change plans any time. Nothing is locked in.

SEE WHAT'S HAPPENING IN YOUR BODY
• Live fasting stages: blood sugar falling, fat burning, ketosis, autophagy
• Know exactly when the next stage begins
• Plain-language explanations of what your body is doing and why

A FASTING TRACKER THAT KEEPS YOU ON TRACK
• Reminders when your fast starts and ends
• End your fast straight from the notification
• Edit your start or end time when life gets in the way
• Daily streaks that reward consistency, not perfection
• Home screen widget, so your fasting timer is always a glance away

A PROTEIN TRACKER APP BUILT IN
• Log protein and water right from the timer
• Get a daily protein target based on your body and goal
• AI protein calculator: type a food and ONE finds its protein for you

WEAR OS: FAST FROM YOUR WRIST
• Start and end a fast from your watch
• See time fasted, time left and your current stage at a glance
• Tile and watch face complication included
• Stays in sync with your phone automatically

SEE YOUR PROGRESS
• Every fast is logged automatically
• Streak calendar and total fasting hours
• Weight and water tracking
• Weekly and monthly AI coach reports that read your data, tell you what changed, and suggest what to try next

BUILT TO STAY OUT OF THE WAY
• Start fasting in under a minute, with no sign-up
• Optional backup, so your history follows you to a new phone

ONE Plus unlocks full history, trends, the AI coach, the AI protein calculator, custom plans and cloud backup. The fasting timer and the Wear OS app are free, forever.

Looking for a simple fasting tracker app that you'll actually stick with? Download ONE and start your first fast today.
Intermittent fasting & protein tracker. Fast track your results!
Updated on
Oct 9, 2026

Data safety

Safety starts with understanding how developers collect and share your data. Data privacy and security practices may vary based on your use, region, and age. The developer provided this information and may update it over time.
  • This app may share these data types with third parties
    Personal info, Financial info and 3 others
  • This app may collect these data types
    Personal info
  • Data isn’t encrypted
  • You can request that data be deleted

What’s new

What's new in 1.4.0:
• Wear OS app: start and end fasts from your watch, with a tile and complication
• Home screen widget to track your fast at a glance
• Redesigned timer: a bigger ring and a clearer view of your fasting stages
• Edit your fast's start and end times right on the timer
• Log water and protein from the timer screen
• Fixed a bug that could remove a fast that was still running