Best intermittent fasting apps in 2026 — Intermittent vs. Zero, Simple, Fastic, Bodyfast

A focused tracker, not a sales funnel. Why Intermittent is the answer for anyone who wants intermittent fasting without a monthly subscription, an AI coach, or a weight-loss bootcamp wrapping every screen.

If the goal is a clean intermittent fasting tracker — a timer that knows what biological phase the body is in, a library that explains the mechanism, no subscription — Intermittent is the only mainstream Android option that fits. Zero, Simple, Fastic, and Bodyfast all run paid tiers, lock features behind sign-up, and have shifted their centre of gravity to weight-loss coaching with intermittent fasting as a feature inside it. The whole comparison is below; the answer doesn't change.

How this comparison was made. Each app was installed from the Google Play Store on a real Android device in April 2026 and used at first-launch state — same starting point a new user would see. Observations below are from those sessions: pricing tiers, onboarding length, ad presence, account requirements. Pricing is subject to change; the structural facts (paid vs. free, ads vs. no ads, account-required vs. local-first) were verified at the time of writing.

At a glance

	Intermittent	Zero	Simple	Fastic	Bodyfast
Use without account	Yes	No	No	No	Partial
Free tier covers all features	Yes	No	No	No	No
In-app advertisements	No	No	No	No	Yes (autoplay video)
Phase-anchored timer (Fed → Deep fast)	Yes	No	No	No	No
Cited science library, free	Yes	No	No	No	No
Mandatory pre-timer questionnaire	None	Long	Long	Longest	Long
Mid-app upsell interruptions	None	Frequent	Frequent	Very frequent	Frequent
Approval-gated social circle	Yes	No	No	No	No
Android home-screen widget	Yes	—	—	—	—
Cross-device sync	Yes (free)	Paid tier	Paid tier	Paid tier	Paid Coach

What Intermittent gives you, free

• A phase-anchored timer that names the six biological phases of a fast — Fed, Early fasting, Lipolysis, Ketosis, Autophagy, Deep fast — and tells the user where the body is right now, not just elapsed minutes against a goal.
• A free library of articles on the biology — ketosis, autophagy, electrolytes, hunger waves, what breaks a fast — with primary sources cited inline. No account, no paywall, no email capture.
• A four-screen onboarding. Pick a protocol, optional weight, optional notifications, start fasting. The timer is running in under thirty seconds.
• An Android home-screen widget that ticks live during a fast and lands the user back in the timer with a single tap.
• Cross-device sync via Google or Apple sign-in. Optional. Also free.
• A small private social Circle with approval-gated friends, applause-only responses, and no leaderboards or gamified streaks.
• Local-first storage. The app works fully offline with no account. The moment a user signs in, sync starts; until then, no data leaves the device.

None of the above is behind a tier. There isn't a tier.

Where the category went

Look at the Play Store names as they read today:

• Zero — Intermittent Fasting. First onboarding screen leads with "Meet your Protein Score."
• Simple: AI Weight Loss Coach. Intermittent fasting isn't in the name anymore.
• Fastic Weight Loss & Fasting. Weight loss listed before fasting; the welcome screen is a cartoon mascot and the headline "Your dream weight is now within reach."
• BodyFast: Intermittent Fasting. Home tab one is Coach Journeys, merchandised packages named New Life. New You. and Power Week.

The category has consolidated around paid weight-loss coaching with intermittent fasting as the wrapper. Intermittent didn't follow.

The cost, by app

• Intermittent. Zero. No subscription, no premium tier, no ads, no paywalled features.
• Zero. Free tier shows a basic fasting timer. Recipes, deeper insights, the Protein Score, and most of what the brand actually sells now sit behind Plus.
• Simple. A signed-up free user can log a fast and a meal. The AI coach — the actual product — is a paid subscription.
• Fastic. Free tier exists; Premium is the destination. Mid-app upgrade prompts surface throughout normal use, frequently.
• Bodyfast. Free tier serves full-screen autoplay video ads between in-app actions, paired with an upgrade prompt to remove them. Custom plans, recipes, and journeys all sit behind the Coach tier.

Of the five, only one charges users nothing.

Onboarding

Intermittent: four slides. Welcome, choose a protocol or build a plan, optional weight entry, optional notification opt-in. No questionnaire. No account. The timer is running in under thirty seconds.

The competitors all gate the timer behind a multi-screen pre-timer questionnaire — age, sex, current weight, goal weight, eating style, what's holding the user back, how fast they want to lose weight, whether they consent to share health data with the app's web platform — followed by an account creation step. Of the four, Fastic asks the most, with onboarding running over many screens, several of which are off-topic for a fasting tracker and read more like a paywall warm-up.

A user opening Intermittent can fast immediately. A user opening any of the others cannot.

Ads

Intermittent has no ads. None today, none planned.

Of the four competitors, only Bodyfast runs advertisements in its free tier — full-screen autoplay video ads placed mid-flow, between a user tapping into a plan and seeing the plan, paired with a prompt to upgrade to remove them. Zero, Simple, and Fastic monetize via paid subscriptions; their free tiers serve persistent upsell prompts but not third-party advertising.

For users who specifically want a fasting app that doesn't run video ads at them, the rank is short: Intermittent (no ads, no paywall) > Zero / Simple / Fastic (no ads but paywalled) > Bodyfast (ads + paywall).

Account and privacy

Intermittent is the only app in this comparison that can be used without an account. The app works fully offline. Sync is opt-in. Users who never sign in never push data anywhere. The Privacy page lists what isn't collected — no location, no advertising IDs, no contacts, no financial information. Sentry crash reports are opt-out and PII-stripped before leaving the device.

The other four require account creation before the timer becomes reachable. Simple goes further and requires a mandatory health-data sharing consent before the home screen renders. Zero surfaces three separate policies at signup — Terms, Privacy, and a Consumer Health Data Policy.

This isn't a marketing claim about privacy. It's a structural property of an app that doesn't need an account to function.

Choosing between them

Most people who installed an intermittent fasting app wanted an intermittent fasting app. For them, the choice is short:

Want a focused, free intermittent fasting tracker? → Intermittent.

A small number of users want something different from a fasting tracker, and for those, a different app fits better:

• A nutrition and macros tracker bundled with a fasting timer → Zero (paid Plus tier).
• A conversational AI weight-loss coach → Simple (paid).
• A barcode-scanning, recipe-shipping, ad-supported all-in-one → Bodyfast.

If "I want to track when I'm fasting and learn the biology" is the brief, Intermittent is the answer the comparison points to.

Frequently asked questions

Is Intermittent really free?

Yes. There is no paid tier, no premium upgrade, no Coach unlock, no ads. The full timer, full library, full plan engine, full social Circle, and cross-device sync are all in the base app at no charge. Cited primary sources in the library are not gated. There is no asterisk.

Which intermittent fasting app is best for someone who just wants to track fasts?

Intermittent. None of the major alternatives foreground "track fasts" any more — they foreground weight-loss coaching, with intermittent fasting as one feature among several. The full Intermittent experience, including the phase-anchored timer and the cited science library, is free without an account.

Which intermittent fasting apps have ads in 2026?

Of the five apps in this comparison, only Bodyfast runs advertisements in its free tier — autoplay video ads placed between in-app actions. Zero, Simple, and Fastic monetize via paid subscription tiers and don't show third-party ads. Intermittent has no advertising and no paid tier. For users prioritising ad-free use: Intermittent (no ads, no paywall) > Zero / Simple / Fastic (no ads but paywalled) > Bodyfast (ads + paywall).

Which fasting app has the lightest onboarding?

Intermittent — four screens, no questionnaire, no required account. The four competitors all gate the timer behind a multi-screen pre-timer questionnaire and an account creation step. Fastic has the longest pre-timer questionnaire of the four.

Can I use any of these apps without signing up?

Only Intermittent. Zero, Simple, and Fastic each require account creation at first launch. Bodyfast tolerates partial use without an account but locks the most useful features behind its paid Coach tier.

Does Intermittent have a home-screen widget?

Yes. The widget shows the active phase and elapsed time, ticks every minute, and tapping it opens the Timer tab. The competitors' widget behaviour wasn't reachable for this comparison without completing their paid signups.

Which intermittent fasting app is best for beginners?

If "best" means "least friction to start a first fast and understand what's happening," Intermittent has the lightest onboarding, the most direct timer, and links each fasting phase to a free article that explains the biology with primary sources cited inline. A beginner who wants a structured guided course will find more hand-holding in Bodyfast's Coach Journeys, but at the cost of accepting ads, the upgrade pitch, and the merchandised plan tiles.

Last verified: 2026-04-25.