Comparison

Fast vs FastFlow

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

Head to head
About

Fast

Features
Read full description

Feel Better. Stay on Track. Your Fasting Journey, Made Simple. Build healthy habits and stay in tune with your body—without the clutter or complexity. This beautifully simple app helps you track intermittent fasting in a calm, intuitive way that fits effortlessly into your daily routine. Why You’ll Love It: • No accounts, no login, no tracking. Your data, your device. • Gentle, Simple Tracking: Start and stop fasts with just a tap. No distractions, just a clear view of your progress. • Apple Watch Ready: Track your fasts directly from your wrist—even without your phone nearby. • At-a-Glance Insights: Stay mindful of your fasts with elegant widgets on your iPhone and Apple Watch. • Private by Design: Your data is stored securely in your personal iCloud account. Nothing ever leaves your devices. Whether you’re fasting for wellness, focus, or energy, this app is your quiet companion on the journey.

About

FastFlow

Features
Read full description

FastFlow turns intermittent fasting into a guided, personalized journey — and it reads your Garmin's biometrics in real time so you can actually see your fast working. Connect a compatible Garmin watch and FastFlow maps your fast through six metabolic stages — Fed, Clearing, Shifting, Burning, Cleansing, Renewing — using your live heart rate, HRV, Body Battery, and stress. Instead of a plain timer, you see what's happening inside your body, and what to do at each stage. WHY FASTFLOW - Live biometrics, not just a clock. Your Garmin data drives the ring, so every stage is grounded in what your body is actually doing. - Know what to do, hour by hour. Each stage suggests the right activities — sleep through the early hours, deep work and fasted training in Burning, rest in the long stages. - A smart end-of-fast review. Log how the fast went in two taps; FastFlow reviews it against your own baseline, entirely on your device. - Break your fast the right way. A guided, step-by-step refeeding flow with gentle food suggestions — plus a shop for break-fast staples like bone broth and electrolytes. - Build the habit. Streaks, a color-coded calendar of your fasts, and per-stage insight. LIVE ACTIVITY + DYNAMIC ISLAND Track your fast from the Lock Screen and Dynamic Island — the stage and elapsed time stay current at a glance. PRIVATE BY DESIGN FastFlow has no account. Your fasting and health data is processed on your device and stored in your own private iCloud. We don't collect, sell, or share it. REQUIRES A GARMIN Live biometric sync requires a compatible Garmin watch with the FastFlow watch app (available on the Garmin Connect IQ Store). You can also use FastFlow phone-only: start/stop fasts, follow the stage journey, log break-fasts, and keep your history. FASTFLOW PREMIUM A subscription unlocks live Garmin biometric sync, full history and insights, and Live Activity. - Monthly and annual plans, with a free trial. - Payment is charged to your Apple ID at confirmation of purchase. - Subscriptions renew automatically unless turned off at least 24 hours before the end of the period. - Manage or cancel anytime in your App Store account settings. - Terms: https://fastflowapp.com/terms - Privacy: https://fastflowapp.com/privacy FastFlow is a general wellness and fasting-tracking app. It is not a medical device and does not provide medical advice, diagnosis, or treatment. Any biometric data shown comes from your own consumer fitness wearable and is for general wellness information only. Always consult your doctor before making any medical decisions, starting a fast, or changing your health routine.

Screenshots

Fast4 screens
FastFlow4 screens

Verdict

The call

The clearest difference is in-app purchases: Fast at none against FastFlow's 2. Fast also leads on device support (3 vs 1). FastFlow's advantage is iOS requirement (16.4 vs 26.0). On price and ads 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. FastFlow sells 2 in-app purchases, starting at $4.99 per month. Fast asks for nothing beyond the download.

Scorecard3 real differences · 3 level
Fast versus FastFlow: the parameters behind the verdict, then further details
ParameterFastFastFlow
PriceFreeFree
Update frequencyEvery 2 weeks—
AdsNoNo
In-app purchasesNo — betterYes
DevicesiPhone, iPad, Apple Watch — betteriPhone
Requires iOS26.016.4 — better
Further details — not scored
Size35 MB3 MB
Age rating4+4+
DeveloperCodeHive GCVDaSecure Solutions LLC

In-app purchases

None

Fast

No in-app purchases

2 purchases

FastFlow

Subscriptions2
  • Monthly$4.991 Month
  • Annual$39.991 Year

Questions

Is Fast free?
Fast is free to download, with no in-app purchases.
Is FastFlow free?
FastFlow is free to download, with in-app purchases available.
Do Fast or FastFlow have ads?
Neither Fast nor FastFlow shows ads.

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