Zero is the all-in-one fasting tracker and nutrition app built for real results. Most fasting and weight loss apps stop at simply tracking fasts or calories. Zero connects the full picture — fasting, protein, meals, hydration, and habits — so you actually change your body composition, not just your eating schedule.
Here’s how Zero helps you get there:
• Track your intermittent fasting — Engage timers, streaks, and insights keep you stay motivated and consistent across your entire fasting journey.
• Log meals the smart way — Skip the tedious manual meal entry routine. With Zero Plus, snap a photo and get instant macros, protein composition, and clarity on how effectively your meals support your goals. Your first meal logs are on us, so you can try it before you subscribe.
• Hit your Protein Score — Zero Plus tracks a personalized daily protein target that adapts to your weight and goals. Better protein = better satiety, better muscle retention, better weight loss. Zero makes it automatic.
• Complete the equation: Fasting + Protein — Most people fast or track meals. Zero brings them together so you lose weight, protect muscle, and avoid the pressure and guilt of traditional calorie trackers.
• Stay hydrated to power your fasts — Water tracking with Zero Plus helps you maintain energy, reduce cravings, and support metabolic function throughout the day.
• Build healthy habits that actually matter — Track movement, sleep, mood, and other daily pillars that reinforce your fasting and fueling routine.
• Challenge yourself — Hit protein targets, maintain fasting streaks, and stay accountable with motivating challenges built around outcomes, not vanity metrics.
• Learn the real science — Understand how fasting, protein, and hydration work together for sustainable weight loss and metabolic health — with insights from leading experts.
• See measurable progress — Watch your streaks grow, your protein consistency rise, and your body composition improve with clean, insightful trend views.
Whether you’re starting out or optimizing an existing routine, Zero gives you the structure, guidance, and clarity most apps miss.
Zero is not a medical device and does not provide medical advice, diagnosis, or treatment. Always consult your doctor or qualified healthcare provider before making any changes to your diet, fasting routine, or health regimen.
Zero is free to download, with fasting timers, streaks, weekly trends, expert articles, and challenges included. Zero Plus is an optional subscription that unlocks photo meal logging and your Protein Score, water tracking, custom fasts and saved presets, Fat-Burning Mode, the mood journal and daily habit insights, premium articles and Plus-only challenges, and monthly, yearly, and correlated charts. A free trial is available.
Payment for Zero Plus will be charged to your Apple 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 in your Account Settings.
Read more terms & conditions:
Terms of use: https://www.zerolongevity.com/terms-of-use
Privacy policy: https://www.zerolongevity.com/privacy-policy
I’ve clocked in more than 1100 fasts on Zero, so it’s clearly been with me for a while. The app has very slowly improved in the sense that any noticeable bugs are gone.It’s changed a bit in other aspects, but TBH not in any way I care for. Too much content for its own sake…I wanted a reliable fast tracker that kept track of my history. That’s really most of what you need.Unfortunately, like many apps of its kind — and in general —, it has expanded the feature set to accommodate more people, and in that process became a bit overkill. And all that came with a price tag of nearly 80€/year, which would place it amongst the most expensive software I use *of all kinds*. This makes Zero almost twice the price of, say, WebStorm; more expensive than a non-renewable purchase of Things on 2 platforms; or even more expensive per year than Little Snitch and Hazel *combined*. It’s not an apples to apples comparison, but then again this is a fancy stopwatch with some blog posts attached.I don’t doubt at all the team deserves to be well compensated for it, and I’m an app developer myself so the price tag is whatever they consider necessary. I just don’t feel like it’s doing much with that renewable subscription.Still, very pretty, reliable, and does the job. Update (Oct. 2023): Zero lost all my data when switching phones, by no longer being able to find my Apple ID account…
Developer Response
Hi there - So sorry to read you're unable to access your account. We'd like to help locate your account's login method (which is tied to your in-app data). Please send an email to support@zerolongevity.com and our support team will assist you directly. –Team Zero
Bugs
ChocoIat
The "End fast" button doesn't work 80% of the time. I need to press it 7-8x before it works.
Developer Response
Hi there — Thanks for reaching out with that feedback, sounds like you may have run into a bug. If you’d like help with this or have further questions, please contact our support team at support@zerolongevity.com. We'll be on the lookout for your message. —Team Zero
Fasting, hands-free.
This update makes Zero easier to reach when you're on the go, with enhanced Siri support for fasting and a quicker way into meal logging.
• Fasting with Siri: Start, end, or check on your fast just by asking — try "Start my fast in Zero." Zero now works with Siri automatically, with no setup needed, and is updated for the new Siri in iOS 27.
• Quicker Meal Logging: Add the new Log Meal control to your Lock Screen, Control Center, or Action button to jump straight into logging a meal. Requires iOS 18 or later.
• Bug Fixes: Fixed an issue that could prevent logging your weight on iOS 27, and improved compatibility with the latest version of iOS.
Version 7.15.0
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
Identifiers
Usage Data
Diagnostics
Privacy practices may vary based, for example, on the features you use or your age. Learn More
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
Size
204.8 MB
Category
Health & Fitness
Compatibility
Requires iOS 17.0 or later.
iPhone Requires iOS 17.0 or later.
Apple Vision Requires visionOS 1.0 or later.
Apple Watch Requires watchOS 10.0 or later.
Languages
English
Age Rating
16+
16+
This app is rated 16+ with content restrictions.
Some content may be rated higher, and may therefore be restricted and managed by the developer through in-app controls.
Zero Longevity Science, Inc. has identified itself as a trader for this app and confirmed that this product or service complies with European Union law.
DUNS Number 081216076
Address 100 24th Street W Suite 1-1114 Billings Montana 59102 United States
