Unlock the power of intermittent fasting to lose weight and improve your metabolic health.

Zero’s expert guidance, goal-based fasting plans, personalized insights, and advanced tracking can help you manage your weight, boost energy, reduce inflammation and live a longer, healthier life.

Rooted in scientific research and backed by Zero’s Chief Medical Officer Dr. Peter Attia, use Zero to reach healthy weight loss goals and enjoy your favorite foods no matter what diet you follow - keto, low-carb, medetertanian, vegan, vegetarian, paleo, macros, intuitive eating or calorie counting.

Featured in Women’s Health, The Tim Ferriss Show and more, Zero is the world’s most popular fasting app.

Get started for free today.


TIMER - Set goals, track your fasts, and stay on track with Siri support and iOS 14 widgets.

CUSTOM PLANS - Personalized protocols and adaptive recommendations help everyone from first-time fasters to advanced practitioners.

SUSTAINABLE APPROACH - Adjust how long and how often you fast and enjoy your meals when you’re not fasting.


PERSONALIZED INSIGHTS - See how your fasting practice correlates with health markers like weight, heart rate, sleep, and blood glucose. Spot trends and adjust behaviors to stay on target.

FASTING ZONES - Understand what's happening in your body to stay motivated to reach your goals.

JOURNAL - Reflect on how you feel during your fasts. We'll graph your moods so you can track trends over time.


PREMIUM CONTENT - Cut through the noise with an exclusive, ever-growing library of hundreds of videos, articles, audio segments, and Q&As from health experts like Dr. Peter Attia and Kanchan Koya PhD.

HOLISTIC APPROACH - Learn about multiple facets of health, including metabolic health, mindful eating, gut health, inflammation, blood sugar, hormone health, hunger management, sleep health, exercise, and more.

ASK ZERO - Submit your questions and tune in to get answers from experts.


CHALLENGES - Fasting is more fun with friends. Join seasonal events and group fasts that align with your goals. Stay motivated with guidance from experts and a chance to win exclusive prizes.

ACHIEVEMENTS - Unlock achievements to celebrate fasting milestones and stay motivated.

• 13-HOUR FAST, based on research by Dr. Satchin Panda (Salk Institute), this 13-hour or “Circadian Rhythm Fast” aligns your eating window with your body’s clock.

• 16-HOUR FAST, or the 16:8 Intermittent Fast, used by celebrities, athletes, and millions of Zero users to manage weight.

• 18-HOUR FAST, or 18:6 for more advanced fasters.

• Other popular fasts include OMAD (one meal a day), 20:4 fast and custom prolonged fasts up to 7 days

Track your progress on your iPhone or Apple Watch with Apple Health integration to sync your weight, resting heart rate and sleep.

Download the Zero app to get started for free, or unlock premium features with Zero Plus.

Payment for Zero Plus will be charged to your iTunes Account when you subscribe. Subscriptions automatically renew unless auto-renew is turned off at least 24-hours before the end of the current period. Manage your subscription by going to your Account Settings.

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What’s New

Version 4.20.0

Thanks for using Zero! Today's release includes some updates to the Timer, as well as a number of bug fixes and performance improvements. We have several exciting new updates to share with you all soon, and as always, if you run into any issues, please let us know at

Ratings and Reviews

4.8 out of 5
33.5K Ratings

33.5K Ratings

Cdourzi ,

No editing?

We have to sign up now and we can’t edit fasts anymore. Going to look for a new app :(

dominaTrix66 ,

Fasting companion

I do full extended fasts, and I’m always alone. This app is a personal cheerleader and companion during your fast. And you get to see that other people on this planet are fasting too—you’re not alone. You can tract your stats, even your mood and see your progress. This is huge for motivation.

This app is a must have for anyone fasting.

It makes a huge difference.

One function I wish this app had was a pop up of the physiological milestones that occur during a fast, ie: Day 2 you are now suppressing the hormone Ghrelin and autophagy is commencing...something like that would be hugely motivating. And I’ve not seen it anywhere.

Love this app.

Wallacker ,

Was good, once

Hooray, unneeded update to add a pay version. Only reason I chose this app to start with was that it was simple.

Developer Response ,

Hi there, thanks so much for reaching out! To clarify, Zero Plus is an optional premium upgrade. The free Zero app will always be available to you free of charge and there's absolutely no requirement to upgrade to a subscription. If you have any further questions or if there's any way I can further assist please don't hesitate to reach out at ' Best wishes, Michelle

App Privacy

The developer, Big Sky Health, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer's privacy policy.

Data Linked to You

The following data may be collected and linked to your identity:

  • Health & Fitness
  • Location
  • Contact Info
  • User Content
  • Usage Data
  • Diagnostics

Privacy practices may vary, for example, based on the features you use or your age. Learn More


  • Family Sharing

    Up to six family members will be able to use this app with Family Sharing enabled.

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