Comparison

ChronoFast AI vs Ketl

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

ChronoFast AI

This app acts as an AI coach for intermittent fasting, helping users understand if their food intake breaks their fast. It provides detailed metabolic insights, tracks progress, and offers social features for fasting with friends.

Highlights
  • AI-powered 'Did I Break My Fast?' analysis
  • Live Activity and Dynamic Island integration
  • Detailed metabolic stage tracking
  • Apple Health integration for activity and sleep
  • AI meal scan and barcode scanning
  • Social fasting features and leaderboards
Features
Read full description

Most fasting apps are a countdown. ChronoFast AI is a coach that answers the question you actually have at hour 11: does this break my fast? DID I BREAK MY FAST? Type what you had, or snap a photo of it. The AI weighs it against the exact stage your fast is in and gives a straight verdict — Intact, Impacted or Broken — with what it does to insulin, fat burning and autophagy. If it is genuinely broken, one tap ends or restarts the timer. ON YOUR LOCK SCREEN ALL DAY Start a fast and the Live Activity stays with you for the whole thing, drawing the same dial the app does: a ring sweeping through every stage colour, each one checked off as you pass it, with your stage, time elapsed, when the next stage lands and the clock time you finish. Add 250 ml logs your water; End fast opens the app's own confirmation, with undo. The Dynamic Island gives the dial and percentage at a glance, the full status on a press and hold — and one switch in Settings turns it all off. A TIMER THAT SHOWS ITS WORKING • A live dial with your percentage of goal at the centre • A 24-hour band that shows when you eat, and whether your window is drifting later • A named stage track — Fed, Fat Burning, Ketosis, Deep Autophagy — hour-stamped for your plan • Home Screen widgets in two sizes, plus a Lock Screen circular accessory • 12:12 through 20:4, 23:1 OMAD, extended 24h to 72h fasts, or your own custom window • Streak repair: one free rescue a month for a single missed day SCIENCE YOU CAN CHECK Every metabolic stage carries its source — the NEJM fasting review, the Nobel-winning autophagy research — named, dated, and honest where the evidence is still early. The Metabolic Wave glucose curve is clearly labelled as an educational simulation modelled from your clock, never measured from your body. No bro-science, no numbers we cannot know. YOUR ACTIVITY AND SLEEP COUNT With Apple Health connected, ChronoFast reads sleep, resting heart rate, HRV, steps, workouts and active energy, each compared against your own 7-day average. A fasted walk shows as real metabolic progress. A rough night, and the app eases off instead of pushing you to extend. It writes back too — water, weight, nutrition and completed fasts — with a switch for each. FOOD, WATER AND WEIGHT IN ONE PLACE • AI meal scan from a photo, plus barcode scanning for packaged food • Calories and macros on one compact card, with rings that fill as you log • Hydration goal set from your body weight, with reminders that never collide with a stage alert • Weight trend with a projected goal date that shows its confidence band YOU ARE NOT ALONE AT HOUR 16 Fast with buddies added by QR or friend code, see who is fasting right now, send high-fives, join weekly and monthly challenges, log how the fast actually feels on a 1-5 mood scale, and climb a global leaderboard. A shareable weekly recap rolls up your last 7 days. PROGRESS THAT MAKES SENSE A 28-day consistency grid read three ways — fasting, weight and water — a day-by-day log for every metric, and plain-language observations about your last four weeks, each with its evidence. BUILT TO BE TRUSTED 18 languages including full right-to-left Arabic. An adults-only age gate before any health question. A legal centre in plain English, explicit AI-processing consent, and crash reports that never carry your name. Moving phones? Export everything at once. FREE AND PRO The timer, stages, logging, community and daily AI coaching are free. Pro unlocks unlimited AI insights and food scans, all five coach personas, predictive goal dating, the glucose chart and a 100% ad-free app. IMPORTANT ChronoFast AI is for education and general wellness, not a medical device: it does not diagnose, treat or prevent any condition, and AI output can be wrong. Talk to a doctor before fasting if you are pregnant or breastfeeding, under 18, diabetic, on medication, or have a history of disordered eating. Terms of Use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/

About

Ketl

Features
Read full description

Fast smarter. Not harder. Ketl is a fasting tracker that shows you what's actually happening inside your body — hour by hour, milestone by milestone. Not just a timer. A live journey through your own biology. THE FASTING APP THAT GETS IT Most fasting apps are glorified timers with a paywall. Ketl is different. A beautiful gradient wheel tracks your fast while science-backed milestones celebrate what your body is unlocking in real-time. Fat burn, ketosis, autophagy — you'll see it all happen, not just read about it. HOW IT WORKS Start your fast. Watch the wheel fill. As hours pass, milestones light up showing exactly what's changing inside — when you start burning fat, when ketosis kicks in, when your cells begin cleaning house. Every milestone comes with real science, not fluff. It's like a nature documentary narrating what's happening inside you. FASTING PLANS WITH PERSONALITY - 16:8 "The Explorer" — The perfect starting point - 18:6 "The Pathfinder" — Push into autophagy territory - 20:4 "The Warrior" — Deep ketosis and strong autophagy - OMAD "The Monk" — One meal. Full focus. - 5:2 "The Strategist" — Strategic weekly fasts - Custom "The Architect" — Build your own from 12h to 7 days BODY SCIENCE MILESTONES - 4h: Blood sugar stabilizing - 12h: Fat burn ignition — your body switches fuel sources - 14h: Growth hormone rising — protecting muscle while burning fat - 16h: Ketosis begins — your brain's premium fuel - 18h: Autophagy initiating — cells taking out the trash - 24h: Deep autophagy — major cellular renovation - 36h: Immune system boost - 48h: Stem cell activation - 72h: Full system reset Every milestone is a celebration, not a textbook. CORE FEATURES - Gradient Wheel Timer: Beautiful animated ring that fills as you fast - Milestone Celebrations: Unlock body science cards at each stage - Fasting History: Every fast logged with duration, milestones reached, and notes - Water Tracker: Quick-add buttons, daily goal, and intake log - Meal Tracking: Log meals with photos and notes when you break your fast - Smart Notifications: Get notified when you hit each milestone - Home Screen Widgets: Live fasting timer right on your home screen - Body Science Library: Learn what happens at every stage of fasting STATS & TRENDS - Weekly fasting charts - Average duration and completion rate - Milestone hit rates across all your fasts - Current and longest streak tracking - Full fasting history with ratings and notes MAKE IT YOURS - 8 Timer Themes: Ember, Ocean, Aurora, Sunset, Midnight, Neon, Rose Gold, Monochrome - Rate and review your fasts - Add notes to remember how each fast felt - Export your data as CSV KETL PRICING Free: - Full fasting timer with gradient wheel - All preset fasting plans (16:8, 18:6, 20:4, OMAD, 5:2) - Milestones up to ketosis (16h) - Water tracking - Meal logging - Fasting history and streaks - Body science library Pro (Monthly or Lifetime): - Extended milestone celebrations (autophagy, stem cells, full reset) - Custom fasting schedules (12h to 7 days) - Detailed stats, trends, and charts - Unlimited meal photos - All 8 premium timer themes - Home screen widgets - CSV data export Your body is already doing incredible things when you fast. Ketl just shows you. SUBSCRIPTION INFO Subscriptions automatically renew unless cancelled 24 hours before the current period ends. Manage subscriptions in your App Store account settings. Payment charged to Apple ID upon confirmation. Privacy Policy: https://damobo.com/ketl/privacy.html Terms of Service: https://damobo.com/ketl/terms.html Support: support@damobo.com

Screenshots

ChronoFast AI4 screens
Ketl4 screens

Verdict

The call

The clearest difference is ads: Ketl at none against ChronoFast AI's shown. On price, in-app purchases, device support and iOS requirement there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. ChronoFast AI sells 2 in-app purchases, starting at $4.99 per month and Ketl sells 2 in-app purchases, starting at $2.99 per month. Whichever you choose, the download price is not the number that matters.

Scorecard1 real difference · 8 level
ChronoFast AI versus Ketl: the parameters behind the verdict, then further details
ParameterChronoFast AIKetl
PriceFreeFree
Rating5.0 (1 ratings) — better—
Number of ratings1 — better—
Update frequencyEvery 2 weeks—
AdsYesNo — better
In-app purchasesYesYes
MonetizationFree with in-app purchases—
DevicesiPhone, iPadiPhone, iPad
Requires iOS17.0 — better18.6
Further details — not scored
Size121 MB5 MB
Age rating17+4+
DeveloperSoundarya SrinivasChristopher Mayberry

In-app purchases

2 purchases

ChronoFast AI

Subscriptions2
  • ChronoFast-AI-Monthly-Yearly$4.991 Month
  • ChronoFast-AI-Monthly-Yearly7 Days trial$39.991 Year
2 purchases

Ketl

Subscriptions1
  • Ketl Pro Monthly$2.991 Month
One-time1
  • Ketl Pro Lifetime$19.99

Questions

Is ChronoFast AI free?
ChronoFast AI is free to download, with in-app purchases available.
Is Ketl free?
Ketl is free to download, with in-app purchases available.
Do ChronoFast AI or Ketl have ads?
ChronoFast AI shows ads; Ketl does not.

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