Best Fasting App for Apple Watch: What to Check Before You Install

Quick answer: Far fewer fasting apps have an Apple Watch app than their marketing implies. Of the five popular ones we checked on 5 August 2026, only Zero and Simple list Apple Watch in their App Store compatibility section. BodyFast, Fastic, and our own app, Fasted, do not. If a wrist timer is non-negotiable, that narrows your list to two before you read another word.

Disclosure: Fasted is our app, and it does not have an Apple Watch app. We have written this page the way we would want to read it — the check first, the results second, and our own gap stated rather than worked around. Every claim comes from each app's own App Store listing, checked 5 August 2026 and cited at the end.

"Works with Apple Watch" is one of the loosest phrases in the health app category. It gets used for four completely different things, and only one of them puts a timer on your wrist.

The Four Things "Apple Watch Support" Can Mean

Before comparing apps, know what you are comparing.

A native watch app. A real app on the watch. You can raise your wrist, open it, see the fast running, and usually start or stop it there. This is what most people mean and the rarest of the four.

A complication. The small readout on your watch face. It shows a number without you opening anything. Some apps ship a complication with a watch app; some ship neither.

Notification mirroring. Every iPhone app gets this for free. If your phone shows a notification, your watch buzzes. That is iOS forwarding a message, not a fasting app running on your watch. An app with zero watchOS code will still make your wrist buzz when your window opens, which is exactly why "get alerts on your watch" is such a slippery claim.

Apple Health sync. The app writes to or reads from Health, which the watch also touches. Useful, and unrelated to whether there is a timer on your wrist.

An app can honestly say "works with Apple Watch" while offering only the third one. So check the store page yourself.

How to Check in Ten Seconds

Open the App Store listing on the web or in the App Store app and scroll to the Information section, near the bottom, under Compatibility. Apple lists every device class the app supports — iPhone, iPad, Mac, Apple Vision, Apple Watch — each with its OS requirement.

If "Apple Watch — Requires watchOS 10.0 or later" is there, the app ships a watch app. If Apple Watch is absent from that list, it does not, no matter what the screenshots suggest.

That single check beats every feature grid on the internet, including this one, because it comes from Apple rather than from marketing.

Two caveats. The compatibility row proves a watch app exists; it says nothing about what that watch app can do. Some are full controls, some are read-only readouts, and the only way to tell is the app's own watch screenshots. And Google Play has no equivalent section, so the same ten-second check does not exist for Wear OS — there you are back to reading the description and hoping.

What Five Popular Fasting Apps Actually List

Checked 5 August 2026, straight from each app's own US App Store listing:

App	Publisher	Apple Watch in Compatibility?	Other device classes listed
Zero: Fasting & Food Tracker	Zero Longevity Science, Inc.	Yes — watchOS 10.0 or later	iPhone (iOS 17.0+), Apple Vision
Simple: AI Weight Loss Coach	AM APPS LTD	Yes — watchOS 10.0 or later	iPhone (iOS 18.3+), Apple Vision
BodyFast: Intermittent Fasting	BodyFast GmbH	No	iPhone, iPad, iPod touch (iOS 15.1+), Mac
Fastic Weight Loss & Fasting	HealthVida GmbH & Co. KG.	No	iPhone, iPod touch (iOS 15.6+), Apple Vision
Fasted - Intermittent fasting	Must Have Apps SIA	No	iPhone, iPad (iOS 16.0+), Mac, Apple Vision

Two of five. That ratio is the real story of this search term, and it is why so many people install three apps before finding one that does what they wanted.

Zero's listing goes further than the compatibility row: its update notes describe "a completely redesigned Apple Watch experience," and the description says it "syncs up with apple health." Simple's description lists "iOS Home Screen widget & Apple Health + Watch integration." Those are the two apps making the claim and backing it in the place Apple controls.

If the Watch Is Non-Negotiable

Then your shortlist is Zero and Simple, and the choice between them is not about the watch at all.

Zero is a fasting and nutrition app — timer, streaks, meal logging, a Protein Score, hydration. Its App Store rating was 4.8 out of 5 across 445K ratings when we checked.

Simple is now an AI weight-loss coach with fasting inside it. Its listing is titled "Simple: AI Weight Loss Coach," built around a coach called Avo and photo-based food feedback, at 4.7 out of 5 across 392K ratings.

One is a fasting-first product. The other is a coaching-first product. We have written longer, sourced pieces on both — choosing a Zero alternative and choosing a Simple alternative — that go through the paywalls and the trade-offs properly.

What You Get Without a Watch App

This is the part we can only write honestly by admitting the gap first: Fasted has no Apple Watch app. Its compatibility list is iPhone, iPad, Mac, and Apple Vision. If you want to start a fast from your wrist, we are not your app today.

What it does instead is a home screen widget, on both iOS and Android. In practice that covers more of the real workflow than people expect, because of what fasting actually asks of you.

A fast has two taps in it. Start and stop. Everything between is waiting. A watch app matters most for activities with continuous input — a workout, a run, a set count. A fasting window has almost none.

The check is a glance, not an interaction. "How long have I been going?" is the question you ask eight times a day, and a widget answers it on the home screen without opening anything. That is the same glance a complication gives you, one device further away.

Your phone is already the notification device. Phase changes and window-close alerts arrive on the phone and mirror to the watch anyway, because iOS does that for every app. Nothing about that requires watchOS code.

So the honest framing is this: a watch app makes the two taps and the glance more convenient. It does not unlock a capability the phone lacks. Whether that convenience is worth choosing your entire app around is a personal call, and for some people it plainly is.

If you want to see what a phone-and-browser workflow feels like before committing to anything, the free fasting timer on this site runs the same phase model with no install, and fasting zones shows what each stage of the window is doing.

Questions Worth More Than the Watch Question

Once you have filtered for the wrist, these decide whether you are still using the app in March.

What sits behind the paywall? The feature you use every day should be on the free side of it. Free versus paid fasting apps works through which premium features earn their keep.

Which schedules ship as presets? 16:8 is universal. OMAD, 14:10, and 36-hour fasts are not. Fasted ships six presets — 16:8, 18:6, 20:4, 14:10, OMAD, and a 36-hour extended fast.

Does it need an account? Some apps want an email before showing you a timer.

Does anything keep you honest? Streaks work for some people and not others. Some apps pair you with a partner instead; fasting apps with accountability buddy features covers that approach, which is the mechanism Fasted's Fast Buddy uses.

The full list of what to weigh is in fasting app features that actually matter.

On Android

Wear OS support in fasting apps is thinner still, and the same check does not exist in the same form on Google Play. Fasted has a home screen widget on Android and no Wear OS app. If Android is your platform, the best intermittent fasting apps for Android is the more useful page.

Frequently Asked Questions

Which fasting apps have a real Apple Watch app?

Of the five we checked on 5 August 2026, Zero and Simple list Apple Watch in their App Store compatibility section, both requiring watchOS 10.0 or later. BodyFast, Fastic, and Fasted do not list Apple Watch at all. Check the listing yourself before installing — this changes with updates.

Does Fasted work on Apple Watch?

No. Fasted's compatibility section lists iPhone, iPad, Mac, and Apple Vision. There is no watch app and no complication. It has a home screen widget on iOS and Android, and its notifications mirror to a paired watch the way any iPhone app's do.

Can I get fasting notifications on my watch without a watch app?

Yes. iOS forwards iPhone notifications to a paired Apple Watch automatically. Any fasting app that sends you a phase or window-close alert will buzz your wrist. This is often what "works with Apple Watch" means in marketing copy, so it is not a useful way to tell apps apart.

Do I need a watch app to track a fast properly?

No. A fast needs one tap to start and one to stop, and the rest is waiting. A watch app makes those taps and the periodic glance more convenient; it does not measure anything a phone cannot. If wrist convenience matters a lot to you, it is a fair reason to choose one app over another — just do not expect a different measurement.

Does an Apple Watch app drain the watch battery during a fast?

Not meaningfully, in the way most fasting apps use it. A fasting timer is a start time and arithmetic against the clock, not continuous sensing like a workout. The watch is displaying a number, not measuring you.

Can I start and stop a fast from the watch itself?

That depends on the app, and the App Store compatibility section will not tell you. It confirms a watch app exists, not what that app can do — some are full controls and some only display a running timer. Look at the app's watch screenshots before you commit, and if it matters enough, install and try it inside the refund window.

Is there a fasting complication for the watch face?

Some watch-app fasting apps ship one and some do not, and Apple's compatibility section will not tell you which — it only tells you a watch app exists. Check the app's own screenshots or description for a watch face image. Apps with no watch app, including ours, cannot offer a complication at all.