Zero Fasting reviews
What users love and hate, from real reviews
The category's best-loved fasting tracker that turned a simple timer into a bloated, server-dependent health platform — and in doing so betrayed the very thing its most loyal, multi-year users came for.
What users love
When it works, it's the category's best — a simple, visual fasting tracker
Despite the failures, the core is still praised as the benchmark: a clear progress wheel, a toggle between time-elapsed and time-left, fasting stages, and encouraging notifications near the finish. This legible visualization of progress is exactly why people stay for years and recommend it to IF beginners.
I love that the timer can switch between time passed and time left, the completion wheel showing how far you've gone, and the % that you've completed is awesome.
I love how easy it is to visualize where I am in my fasting
I really appreciate the free version of this app, particularly the encouraging notifications I receive near the end and at the end of my fasts and the two-week calendar overview of fasts I can see at a glance.
Built-in content and fast stages turn the timer into a coach for the hard moment
For beginners the strongest asset is the educational articles, videos and the explanation of what the body does hour by hour. When willpower fades mid-fast, users open the app to re-motivate themselves — the product retains them not with the timer but by answering 'why am I doing this'.
When I'm in the middle of a fast and I start getting weak-willed I am able to use the app to get inspired again and re-motivated to keep going. I am also learning so much about fasting
I now can time myself, know what to eat, and get exercise videos.
I like the addl information articles.
What users hate
A timer that needs the internet breaks the entire point of fasting
The single simplest action — ending a fast so you can eat — was made dependent on a server round-trip. A user stands at the fridge unable to close their fast while the app syncs; for a tool whose only job is to mark a moment in time, that's absurd, and people leave for offline alternatives like Fast Times.
Have convoluted and overwrought an app now that requires Internet to time a fast. Absurd.
the app has to sync with their servers for you to do literally anything, making the process slower and less convenient
I just want to end my fast so I can eat but I've had to close the app multiple times to be able to load so I can end a fast
Years of loyalty became the loudest source of anger
The angriest reviews come not from new users but from 5-7-year veterans with hundreds of logged fasts and long streaks. They're trapped by their data history, watch the app rot, and leave feeling betrayed — which destroys the brand's core asset: word-of-mouth from long-time advocates.
I have been using this app for 6 years. Recently, the user face is not user friendly, more delays, takes a lot of time to open.
I still use it because all my history is recorded here, but the bloat is really getting on my nerves.
Used to be tremendous. I recommended it to so many people. But as per usual it's now bloated and buggy losing focus on what made it great in the first place.
30+ second load times in real time kill the motivation to fast
To start or end a fast at the right minute, users have to relaunch the app several times and wait. For a habit tracker this is fatal: instead of motivation it injects frustration at the exact moment accuracy matters, so people start back-dating their times or quit entirely.
more often than not, the app does not load so I'm unable to accurately start or stop a fast in real time.
the free version is basically overly bloated fancy timer that sometimes takes 30 seconds just to launch.
instead, it adds loads of unnecessary frustration to my life.
A white screen instead of the timer — the core product simply vanishes
The most common failure hits the one thing the app exists for: the main timer screen renders as a blank white box while secondary tabs (calendar, premium) load fine. Users can neither see their current fast nor stop it — the product keeps everything except its reason to exist.
Other options like calendar and the premium features page loads but not the actual timer. Until recently it was a good way to keep track of fasts but the primary function isn't available.
the actual page to track your fast is blank.
When I launch the app, it often displays just blank widget instead of timer. This annoying bug occurs roughly 75% of time.
A mandatory onboarding questionnaire scares people off before the first timer
Just to start a timer, the app forces account creation and a long questionnaire of personal data, then overrides the user's own target with a 'recommended' weight. For the impulsive 'I'll start fasting right now' intent this is too high a barrier — people quit during onboarding before ever reaching the product.
it makes you fill in an entire questionnaire adding quite personal information about yourself
I don't want to fill out. a.goddamn survey to start a timer
I want to lose 3kg (still in healthy BMI for me) and it wouldn't let me select it! It rEcCoMmEnDeD a much higher weight and wouldn't let me set my own goal.
The inability to edit or delete a fast breaks trust in the data
An accidental one-minute fast can't be deleted, and editing times throws an 'overlaps an existing fast' error. For a tracker whose value is a clean history and streaks, one uncorrectable mistake poisons all the stats, and the user leaves to find a tool they can trust.
I accidentally recorded a fast and it doesn't appear in recent fast history so there is no way to delete it.
fasts now CANNOT BE EDITED OR DELETED despite having the edit icon.
I now have a 1 minute fast recorded by error that I can't remove, which messes with all my stats.
Forcing the timer to never go past 'now' blocks recording a real fast
The time selector snaps the choice back if it goes past 'now' and won't save a fast longer than the preset. As a result you can't manually enter an already-running 48-hour fast or log when a fast ran over plan — the app imposes its own model of time instead of the user's reality.
However I cannot manually enter a 48 hour fast that i had started already before downloading this app.
The time selector is annoying, if I go past the current time it forces itself back. JUST LET ME GO PAST IF IT'S CLOSER TO WHEN I STARTED.
it won't let me save a fast that's past what it was set as :/ 13 hours + 45 minutes? no, no, no, better edit that back down to 13 hours. why???
Bloating into a health platform crowded out the simple timer people loved
Goal rings, water, steps, food, sleep and 'four pillars' piled on top of the timer and effectively buried the quick answer to the only question: how long have I been fasting. Users who want fasting alone can't switch the extras off — and leave for minimalist competitors or a paper journal.
It buried the fast duration calendar under the current fast timer and replaced it with the four pillars . I use this as a FASTING App I don't care about water, food, steps
Now it has too many features that I don't need and they have ruined the experience of a simple fast-tracking app for me. I don't need to log my calories, activity, sleep or whatever besides fasting hours. And I can't disable those features.
it's basically a counter, it's trying too hard to do other things and connect to other apps.
Broken streaks and badges snuff out the exact motivator that held the habit
1800+ day streaks suddenly reset, and 50-day badges fail to unlock or repeat themselves. Gamification is the core retention hook of a habit tracker; when it starts lying about progress, the disciplined user loses the reason to keep logging here at all.
My 1800 plus day streak ended.
i have a 51-day streak, and i've still not got my 50-day streak achievement.
Now I have my fasting streak broken, when it's been maintained since 1 Jan 26. Very frustrating!
No watch app keeps users chained to their phone
Many users beg for a Wear OS / Samsung / Garmin version to start and end fasts from the wrist. Fasting is a background process measured in hours, and having to pull out the phone for a single tap rubs against the habit itself; this is the one missing thing keeping the most loyal users from five stars.
By far the best fasting app I've tried. I only wish they had a Wear OS app.
only thing keeping this app from 5 stars is wishing it had a Samsung Watch app/widget.
it desperately needs a Wear OS app for Android watches. I can't check my fasting timer or log progress from my wrist
The widget is the lifeline when the app itself won't load
The home-screen widget became the only way to start and end a fast for users whose app hangs — but it too works only half the time, shows blanks or weird numbers, and won't let you change a fast's length. The last fallback into the product turned out as unreliable as the main one.
I can KINDA use it with the widget, as in I can stop and start it from said widget, but I can't correct times or change it from my previous setting.
Widget stopped working after 3 weeks.
can only start and end fasts through the widget and I can't change the length of the fast from one I choose MONTHS ago.
Broken health integrations force manual entry and kill the convenience
Links to Fitbit, Garmin, Samsung Health, Health Connect and Oura either don't sync or broke entirely after the Google Fit API shutdown. A user who wants 'everything in one place' is forced to re-enter weight, sleep and activity by hand — and leaves for a tool where the data flows in automatically.
fitbit integration does not work. I track my weight data in fitbit, but the data does not sync to zero.
It is unable to track my sleep, steps, weight, body composition etc. which are automatically synced between my phone and watch and that's a huge minus for me as it is derailing my IF journey.
It ignores Health Connect data—why manual entry when it's already shared?
The paywall lands before the product ever proves its value
A full-screen trial pop-up covers the app with no close button and reopens after every swipe, so a new user sees not the timer but a demand for card details. The activation gate slams shut before the first fast — churn happens before the person ever learns what the product is for.
Free trial pop up covers the whole screen and won't go away.
even if I swipe it away it just reopens the trial screen. there's no X button to close it, as a new user it's just horrible experience
I hate when apps have you fill out all your info and sign up THEN ask you to pay