You start the fast, you forget to log it, and by 2pm you're not actually sure how many hours you're into your window. Or you remember to tap start, but forget to tap end, and your "fast" from three days ago is still technically running in the app. Manual fasting trackers ask you to be the reliable one — remembering to open the app at the exact right moment, every day, forever — and that's exactly the part that quietly falls apart first.
The short answer
Yes — FastSyncer auto-starts and auto-logs your fast, so there's no tapping a button at the right moment and no manual day-counting to keep up with. It pairs that automatic tracking with hormone-aware guidance, so you're not just fasting on autopilot, you're fasting on a schedule that actually fits your body. Join the waitlist for free early access when it launches.
Why manual tracking quietly falls apart
Manual fasting trackers put the entire burden of accuracy on you remembering to act at the exact right moment — tap start the second dinner ends, tap end the second you eat again. Life doesn't cooperate with that. You get distracted after a late dinner and forget to start the timer, or you grab a bite before officially "ending" the fast in the app, and now the data in front of you doesn't match what actually happened. Over weeks, small gaps like these add up, and the tracker that was supposed to keep you accountable becomes just another thing to maintain — one more app tab to remember, one more streak to feel bad about breaking.
There's a second, quieter cost too: manual trackers only tell you elapsed time, not whether today's window is actually the right one for your body. A fast that's fine on some days can be genuinely counterproductive on others — in the week before a period, for instance, when rising progesterone makes a long aggressive fast more likely to backfire than help. A stopwatch has no opinion on that. It just counts.
What FastSyncer does for hands-off tracking
FastSyncer's fast starts and logs itself, based on the eating window it's already set for you that day — no tapping start, no forgetting to tap end, no manually counting how many hours you're in. That daily window isn't a fixed number either: it's set by the phase your body is actually in, alongside exactly what to eat to break the fast well and the do's and don'ts that go with it. So instead of a stopwatch that tracks time accurately but has no idea whether today's number is a good one, you get accurate tracking and a window that's actually right for where you are — automatically, every day, without you having to remember or recalculate anything.
What you'd have to do without it
Without it, you're the one responsible for remembering to start and stop a timer at the exact right moment every single day, noticing and correcting the small logging gaps that build up over weeks, and separately figuring out — with no help from the tracker itself — whether the window you're counting is even the right one for where you are in your cycle that day.
When it launches and how to get it
FastSyncer is in final testing now and launching soon on the Apple App Store, with Android support to follow. It isn't downloadable yet — the way to get it first, for free, is to join the waitlist. Waitlist members get early access as soon as it's live.
FAQ
Do I have to manually start and stop my fast with FastSyncer? No — the fast auto-starts and logs itself based on your daily window, so there's nothing to remember to tap.
What happens if I forget to log a meal with most fasting apps? With a manual tracker, a forgotten log usually means inaccurate elapsed time until you notice and fix it. Automatic tracking avoids that gap entirely since it isn't relying on you to act at the right moment.
Does an auto-tracking fasting app still adjust for my cycle? With FastSyncer, yes — automatic tracking and hormone-aware scheduling are the same daily card, not two separate things. The window itself changes with your phase; the tracking just happens to be automatic too.
Is a fasting app that tracks automatically more accurate than a manual one? It tends to be, simply because it removes the most common source of error — forgetting to tap start or end at the right moment, which is where most manual tracking data quietly goes wrong.
Related reading: is there an intermittent fasting app for women? covers the broader case for a women-specific app, and a fasting app that tells you what to eat covers the other half of the daily card — the food guidance that pairs with automatic tracking.