Comparison

Intermittent Fasting vs Shifting Source

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

Head to head
About

Intermittent Fasting

Features
Read full description

Biwo makes intermittent fasting simple and fun. Track your fasting sessions with a beautiful circular timer, see your progress through different fasting phases, and build healthy habits effortlessly. Choose your fasting method: • 16:8 - The most popular method • 18:6 - For experienced fasters • 20:4 - Advanced fasting • OMAD (23:1) - One Meal A Day Features: • Beautiful circular timer with real-time progress • Scan meals for instant calorie & nutrition info • Fat burning & autophagy phase tracking • Complete fasting history • Day Streak tracker to keep you motivated • Start a fast in just one tap • Works completely offline - no account needed • Personalized onboarding Start your fasting journey today with Biwo! Terms of Use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula

About

Shifting Source

Features
Read full description

Shifting Source brings intermittent fasting and the ketogenic diet together in one app. Built as the companion to the book The Keto & Intermittent Fasting Lifestyle, it follows the same principle: understand why it works, and the results will follow. FASTING TIMER WITH LIVE ACTIVITY • Choose 16:8, 18:6, 20:4, OMAD or your own custom window • Follow your fast right on the Lock Screen and in the Dynamic Island • See which phase your body is in along the way, explained in plain language • Extended fasting (48 to 72 hours) with a mandatory safety check before you start KETO WITHOUT THE HASSLE • Log meals with net carbs, fat and protein • TDEE calculator that gives you personal calorie and macro targets • Daily overview of your carbs against your goal TRAINING AND HABITS • Five exercises with instructions and an easier version of each • Log your sets and reps in seconds, including past days • Weekly challenges that grow with you, streaks and badges • Guided breathing exercises for calm and focus INSIGHTS • Calendar with fasts, meals, workouts and wellbeing day by day • Weight, resting heart rate, HRV and sleep from Apple Health • Trends for energy, mood and hunger over time LEARN WHY • Guides and research articles in English, Danish and Swedish • Excerpts from the book, open to everyone • All content is built on peer reviewed research YOUR DATA IS YOURS • No account and no login • Everything is stored on your device • Health data is never shared with third parties • Export or delete everything with one tap Shifting Source does not provide medical advice. Talk to your doctor before starting fasting or a ketogenic diet, especially if you are pregnant, breastfeeding or have a medical condition.

Screenshots

Intermittent Fasting4 screens
Shifting Source4 screens

Verdict

The call

The clearest difference is in-app purchases: Shifting Source at none against Intermittent Fasting's 3. Intermittent Fasting's advantage is update cadence (every 3 days vs every 9 days) and iOS requirement (16.4 vs 26.0). On price, ads and device support 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. Intermittent Fasting sells 3 in-app purchases, starting at $1.99 per 7 days. Shifting Source asks for nothing beyond the download.

UpkeepUpdate frequency

Intermittent Fasting ships an update every 3 days, Shifting Source every 9 days. The most recent releases landed on October 12, 2026 and October 15, 2026 respectively.

Scorecard3 real differences · 3 level
Intermittent Fasting versus Shifting Source: the parameters behind the verdict, then further details
ParameterIntermittent FastingShifting Source
PriceFreeFree
Update frequencyEvery 3 days — betterEvery 9 days
AdsNoNo
In-app purchasesYesNo — better
DevicesiPhone, iPad — betteriPhone
Requires iOS16.4 — better26.0
Further details — not scored
Size68 MB9 MB
Age rating4+12+
DeveloperSylvain FertonsHejlsvig Consulting AB

In-app purchases

3 purchases

Intermittent Fasting

Subscriptions3
  • Biwo Pro Weekly$1.997 Days
  • Biwo Pro Monthly$4.991 Month
  • Biwo Pro Yearly$49.991 Year
None

Shifting Source

No in-app purchases

Questions

Is Intermittent Fasting free?
Intermittent Fasting is free to download, with in-app purchases available.
Is Shifting Source free?
Shifting Source is free to download, with no in-app purchases.
Do Intermittent Fasting or Shifting Source have ads?
Neither Intermittent Fasting nor Shifting Source shows ads.
Which is updated more often, Intermittent Fasting or Shifting Source?
Intermittent Fasting ships an update every 3 days, and Shifting Source every 9 days. Most recently, Intermittent Fasting was updated on October 12, 2026 and Shifting Source on October 15, 2026.

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