Zero: Fasting & Health Tracker 17+

Weight Loss & Metabolic Health

Zero Longevity Science, Inc.

    • Free
    • Offers In-App Purchases


It’s time to get off the dieting seesaw. With Zero, tap into the power of intermittent fasting and other healthy habits to lose weight and build momentum on your journey toward living longer, better.


Zero Members have lost millions of pounds — and that’s no accident. Featured in Good Housekeeping, Men’s Health, Fortune, Techcrunch, Women’s Health, The Tim Ferriss Show, and more, Zero is the world’s most popular fasting app. We help you leverage the science of health in simple ways you can practice daily to build habits that last a lifetime.

Rooted in scientific research and supported by Zero’s world-class Scientific Advisory Board, Zero helps you stack healthy habits to make big changes. You’ll start with one simple habit, like fasting, and build incrementally to improve your exercise, sleep, and more. Get ready to meet a healthier you.


The world's most popular Fasting Timer helps you track your fasts, your progress, and your goals. Start your Timer and stay on target with all popular fasting types, including:

• 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 Members to manage weight and improve metabolic wellbeing.

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

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


Zero’s real-time tips, individualized stats, and Personalized Fasting Zones have helped millions of Members form new habits and achieve their weight-loss and health-gain goals. Discover insights into the changes your body is experiencing and get guidance and accountability along the way.


Fasting is a great starting point for living a longer, healthier life. But if you’re committed to losing weight, gaining health, and boosting longevity, you’ll need to look to the Four Pillars of Health: Nutrition, Activity, Sleep, and Restoration. Zero’s innovative yet simple features help you build lifelong habits across these Four Pillars for accelerated progress and transformative change.


The Loop helps you visualize your journey and celebrate wins across the Four Pillars of Health. As you log or sync your data, you’ll see the corresponding color for each Pillar added to the Loop. Watch as your smart choices add up over days, weeks, months, and years.


Build actionable, data-driven habits with the Habit Tracker. Build consistency by logging your meals, workouts, and more. If you’re using an Apple Watch, Apple Health, Fitbit, Oura Ring, or other apps and wearables, you can sync them with Zero to make this a completely automated experience.


Stay focused with expert-led, science-backed content, community Challenges, achievements, and more. Zero is your partner for building healthy habits that propel you towards better, lasting health.

Download the Zero app to get started with your free trial.

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.

Read more terms & conditions:
Terms of use:
Privacy policy:

What’s New

Version 5.19.0

Thanks for using Zero!

This release includes a number of bug fixes and performance improvements.

If you have any feedback or questions, please contact our Support team at

Ratings and Reviews

4.8 out of 5
416.5K Ratings

416.5K Ratings

reviewer0102030405 ,

Works. 30lbs in 2.5 months

I tried keto, I tried them all. Ended up binging and gaining more back quickly. Found fasting and really knocked out the cravings. With Zero it’s really easy to follow your progress without feeling like you’re staring at a clock waiting to eat again. The articles help ease your mind in the beginning knowing that your hunger pangs and other side effects are common and have reasons. Also how to avoid them and get past the fasting wall. I love the timer and how you can count up or down. I count up because I like seeing how far I can push myself within reason. Counting down makes me want to eat as soon as it hits 0:00. The app has some great tracking features and syncs up with apple health so it takes down the data from my smart scale. Nice knowing that I don’t have to manually enter everything every time. A welcomed improvement would be a way to change the theme of the app to keep it fresh or personalized. Different colors etc. this is a small ask for me. Overall I love the app and have lost 30lbs, 6%body fat in 2.5 months. Tbh I haven’t exercised much at all. Just having my body do what it does and use the energy I’ve stored away for years. But now losing the weight of nearly two full size dyson vacuums, I have more energy both mentally and physically that I now crave to get out and do more

Msatx ,

Literally life changing!

This app has been literally life changing! I accidentally stumbled upon it, just wanted something SIMPLE to log my fasting hours when I first started learning about intermittent fasting but it has sparked my interest in all things related to fasting and health. Im not able to afford paid version and Im extremely grateful that the free version has enough basic information and tracking features to inspire change and at least plant that seed to help people want to learn more, and to want to live with more insight, regardless of economic situation. I was that moron.. the one watching with suspicion while wolfing down pizzas, thought people fasting were just weird food hating extremists. This app has been a revelation, and has been instrumental in opening the door to a new world to me so to speak. It has been invaluable in changing my attitude towards food, fasting, meditation. If you have the means to buy the paid version do it, it will be a small investment for what you get. For me sadly the the price point for the paid version for this and the podcast is not doable but the free version can be very eye opening. Dont just log fasts like I did at first. Dive in and discover everything on the app thats available for free and listen to the podcasts. Fasting and tracking my glucose is now my normal way of life. Grateful.

Online-Seller ,

Used this app to lose almost 70 lbs in 3 months

Then the pandemic happened and I stress ate my way through. Now there’s a vaccine coming and I want to get back on track again. I highly recommend this app for weight loss, health, energy, anti-aging, etc. I wish I’d known YEARS AGO that fasting was healthy and a real way to stay healthy and fit. We were lied to fir decades, but it’s not too late to take control of our bodies and health!

I tried a lot of apps for fasting and this is the most flexible. You can edit your start time after starting the fast so if you forgot to start the app, but remembered to fast, you’re all set. It has some scheduled routines and a lot of freestyle, so lets you do you. Notifications are inspiring as it shows how many other people are fasting. You can eat a wider variety of foods if you fast regularly with far less negative impact on your weight and health. I don’t feel like a failure or dread coming back to this. I got anew iPhone and it triggered me to get going again. I’m really excited! Join me in a fast today!

App Privacy

The developer, Zero Longevity Science, Inc., 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

More By This Developer

You Might Also Like

Health & Fitness
Health & Fitness
Health & Fitness
Health & Fitness
Health & Fitness
Health & Fitness