Intermittent Fasting vs Shifting Source
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Intermittent Fasting
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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
Shifting Source
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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
Verdict
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
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.
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.
| Parameter | Intermittent Fasting | Shifting Source |
|---|---|---|
| Price | Free | Free |
| Update frequency | Every 3 days — better | Every 9 days |
| Ads | No | No |
| In-app purchases | Yes | No — better |
| Devices | iPhone, iPad — better | iPhone |
| Requires iOS | 16.4 — better | 26.0 |
| Further details — not scored | ||
| Size | 68 MB | 9 MB |
| Age rating | 4+ | 12+ |
| Developer | Sylvain Fertons | Hejlsvig Consulting AB |
In-app purchases
Intermittent Fasting
- Biwo Pro Weekly$1.997 Days
- Biwo Pro Monthly$4.991 Month
- Biwo Pro Yearly$49.991 Year
Shifting Source
No in-app purchases
Questions
Is Intermittent Fasting free?
Is Shifting Source free?
Do Intermittent Fasting or Shifting Source have ads?
Which is updated more often, Intermittent Fasting or Shifting Source?
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