Intermittent fasting, for iPhone
A timer tells you a number. At 3pm on hour sixteen, a number doesn’t help.
Maru is built for the part in between — the hours where it is actually hard, not the moment you start or the moment you finish. The home screen has no running clock. That is the product, not an omission.
On device. No account. Nothing leaves your phone.
The present moment
The home screen answers where you are, not how long it has been.
A number is the answer to a question you were not asking. Standing in the kitchen at 3pm, what you want to know is whether this is the normal hard part or a sign that something is wrong. So the home is a state, and it changes only when something has actually changed.
- Settling in The early hours, when it is mostly just new.
- Steady The long middle. Usually there is nothing to say here, so it says nothing.
- Nearing the end Close enough that knowing helps.
- Your window is open Eating time. Not a countdown to the next fast.
- Your window has closed Closing the window is what starts the fast.
- A gentle morning After a night that did not go to plan.
- Resting A planned day off, and it is treated as one.
- Come back when you are ready The invitation to restart. Never a reprimand.
Moments
At most two a day. Frequently none.
Moments are the app speaking first — a short note that arrives because something is true right now. They are not a notification schedule you configure and then learn to ignore. Maru decides whether there is anything worth saying, and the honest answer is usually no.
Two a day, and that is the ceiling
Not a target it tries to reach. Most days it uses one. Some days it uses none, because nothing happened that was worth interrupting you for.
One of a kind per day
Each type of moment can arrive at most once in twenty-four hours, so the same observation cannot follow you around the afternoon.
Quiet hours drop it, never delay it
A moment that would land while you are asleep is discarded rather than saved for the morning. Holding it would only mean saying something stale at a more convenient time.
No premise, no moment
The after-training note needs a real session behind it. The heads-up before an evening out needs something actually in your calendar. When the reason is absent, nothing is sent.
A cap is an unusual thing for an app to want. The reason is simple: the value of Maru saying something depends entirely on it not saying very much.
Week one
It warns you that days two to four are the worst — on day one, before they happen.
“The first week has a shape. Days two through four are usually the hardest — head, energy, mood — and for most people it settles inside a week. Knowing that in advance is most of the trick.”
This is the whole argument for saying it early. A rough Wednesday you were told about is a rough Wednesday. The same Wednesday, arriving unannounced, is evidence that you are not built for this — and that is the conclusion people quit on, not the headache.
The arc runs seven days and it is the same seven days whether this is your first attempt or your ninth. Nothing in it is marked as a second try.
Restarts and rest
Day one is a skill.
Most people who fast for years have had dozens of day ones. Maru treats a restart as exactly that — a thing you get better at — and gives it the same seven-day arc as a first attempt, with nothing anywhere marking it as a repeat.
When it does not go to plan
You are asked what happened, and the options are the real ones: I ran out of time. I got too hungry. My plans changed. I just didn’t. There is no wrong answer there, and picking one changes nothing about your plan.
The notification that follows is an offer, not a summons — log it if it helps, or start again when you are ready. Nothing red, nothing broken, no tally reset to zero in front of you.
A rest day counts as showing up
Maru counts how many of the last fourteen days you were present for. It is a count across a window, not a run — so it cannot be broken, only be lower next time you look. And a planned rest day counts exactly as much as a fasted one. That is not a consolation prize; it is how the number is defined.
You’ve shown up 12 of the last 14 days.
What it learns
Four things about you, each with a bar it has to clear first.
Personalisation in this category usually means the app rearranging itself around whatever you did most recently. These are narrower than that, and slower — every one of them has a minimum amount of evidence before it is allowed to say anything at all.
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The hour you actually struggle
Not the hour the average person struggles. Maru watches for the times you reached for help or ended a fast early, and once it has enough of them it moves its evening check-in to arrive an hour before yours, rather than at everybody’s eight o’clock.
Needs about eight of those moments across two months before it will name an hour.
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How your window’s close lines up with your own sleep
Closing the eating window is what starts the fast, so its timing is the lever. Maru compares when you closed against how you actually slept, and offers to shift the close earlier or later — a suggestion you take in one tap, or ignore.
Needs around ten nights, and it will only ever suggest a close between late afternoon and late evening: a pattern pointing at 4am is telling you about your sample, not your sleep.
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The evening your calendar actually has
If there is a dinner in your calendar at half past seven, forcing the usual window is a plan that fails at eight. Maru suggests a shorter one for that day instead, and gives you the heads-up ninety minutes ahead rather than at the table.
Off until you turn it on, read-only, and it never looks at your calendar before you grant access.
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What you did at the gym
A moment that arrives ninety minutes after you finish training, worded so it fits whether you feel strong or wrecked.
Only for sessions of twenty-five minutes or more — below that it was a walk, not training.
There is one more, quieter than the rest: Maru anchors your day to when you actually wake rather than to a fixed hour on the clock. All of it is worked out on your phone, by the on-device model Apple ships with it.
What it refuses to do
Every other app in this category makes money from your anxiety.
Streaks that punish a missed Tuesday. A goal weight you are behind on. A nudge to push a little harder when the number stalls. These work — that is precisely the problem, because what they are good at is keeping you worried, and worried is not the same as fed, rested or still doing this in March.
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It will never tell you to fast longer
It is the obvious move, it is what the rest of this category reaches for, and it is the one most likely to make your next fortnight harder. Maru notices when your weight has levelled off, and the only things it is able to offer are protein, sleep, or a shift in when your window sits. There is no fourth option for it to pick.
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It never shows you a number from the scale
Not the weight, not the change, not the direction, not the rate. The part of Maru that watches for a plateau cannot pass a number to the part that draws the screen — there is nowhere to put one. And it is off until you switch it on.
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It never sets you a target
No goal weight, no projected date, no bar to fall short of.
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It does not show you a streak
The count you see is how many of the last fourteen days you showed up for, rest days included. It is a window, not a run, so there is no consecutive number sitting there waiting to be lost.
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It will not talk before it knows
Every pattern Maru can describe has a minimum amount of evidence behind it. Below that line it does not soften the claim or hedge it — it tells you how far short it is and says nothing else.
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Red never means you failed
The alarming colour is reserved for deleting things. Ending a fast early is not an error state and is not drawn as one.
Your hours
Not yet. Maru has 3 evenings to go on and wants about 8 before it says anything. A guess from 3 nights would just be a guess.
This is the part you are paying for.
Anything can generate a confident sentence from four data points. Writing the version that admits it has four data points is a decision someone has to make and then defend, over and over, against every easy metric that would perform better in the short term.
Maru is built so those decisions are not slogans. The plateau watcher has no way to hand a number to the screen. The suggestion list has no room for a longer fast. The count on your home cannot be broken. Restraint that lives in the structure of a thing survives contact with a bad quarter; restraint that lives in a mission statement does not.
Privacy
Private by construction, not by policy.
Most apps promise this in a document you are invited not to read. The more useful version of the promise is structural: Maru cannot leak your data to a server because there is no server, and no code in it that could reach one.
There is no account
Nothing to sign up for, nothing to sign in to, no password and no email address. You open the app and it is yours.
There is no server
Not a private one, not an encrypted one. The app has no code for talking to a network at all, so there is no connection to audit.
There are no third-party SDKs
No analytics, no crash reporting, no attribution kit. The project has no outside dependencies whatsoever.
Health data is read, never written
Maru asks for permission to read sleep, workouts, heart rate and weight, and asks for no permission to write anything back. What it reads is used on your phone and stays there.
The intelligence is on the phone too
The model that writes what Maru says is the one Apple ships with iOS. Your fasting, your sleep and your calendar are never sent anywhere to be turned into a sentence.
You can take it all back
Export everything for your own use, or delete all of it, from Settings. There is no copy anywhere else to worry about.
The full detail is in the Privacy Policy.
Pricing
The part you use every day is free, and stays free.
Not free for a fortnight, and not free until it becomes inconvenient. Fasting, logging, your history and your Lock Screen are the daily-useful core, and they are deliberately outside the subscription. Premium is the deeper personalisation on top.
Free, permanently
- Starting, ending and logging a fast
- Your fast on the Lock Screen and the Dynamic Island
- Your history and your rhythm so far
- A plan to fast to
- The ninety-second reset for when a craving lands
- The first two days of the week one arc
- Turning any kind of moment off
Premium adds
- Moments timed to your own hard hour, your training, and when you actually wake
- The full seven-day week one arc, for a first attempt or a restart
- Guidance written on your phone that adapts to how you actually fast
- Deeper rhythm and recovery trends over time
- What your sleep, resting heart rate and steady weeks are saying
- A craving companion that learns from your own difficult hours
- A guided ten minutes for your first plate
- As many changes of plan as your life needs
Yearly
$49.99/year
Seven days free first
Monthly
$7.99/month
Seven days free first
What the money is actually for
A cheaper fasting app is easy to find, and most of them are cheaper because you are not the customer — the engagement is. Streaks, targets and a push to go longer are not there to help you fast; they are there to bring you back tomorrow, and they are very good at it.
Maru has no second business model. It is quiet on purpose, it caps how often it can speak, it declines to comment when it has not seen enough, and it gives up the single most effective thing it could say to you. Every one of those choices costs it engagement. The subscription is what makes them affordable.
Prices shown in US dollars; the App Store charges in your own currency. Cancel any time during the trial and nothing is charged.
The hours in between are the whole thing.
Maru is coming to the App Store for iPhone. It will not have a countdown on its home screen, it will not keep a streak for you, and on the days it has nothing worth saying, it will not say anything.
Not yet downloadable — the app has not been published.