Most fasting apps are timers. Circafast is a coach. Here's the honest difference — including what the other apps do better, and the three things only we do at all.
Sourced from each app's public marketing pages and App Store listings. Last updated May 2026.
| Feature | Circafast | Zero | Fastic | BodyFast |
|---|---|---|---|---|
| Cycle-synced fasting Protocol adapts to menstrual phase | ✓ | ✗ | ✗ | ✗ |
| Zero logging required No food diary, no manual data entry | ✓ | ✗ | ✗ | ✗ |
| Manual Mode (AI off) Toggle AI coaching off, keep your protocol | ✓ | Partial | ✗ | Partial |
| Timer-only mode Pure fasting timer, no coaching | ✓ | ✓ | ✓ | ✓ |
| Explainable AI adjustments Why your window changed, in plain language | ✓ | ✗ | ✗ | ✗ |
| One-click data delete Wipe all your data instantly | ✓ | Via support | Via support | Via support |
| Founding member lifetime pricing Pay once, no monthly fees ever | ✓ $35 | ✗ | ✗ | ✗ |
| AI adjusts from daily check-in 30-second input → tomorrow's window adapts | ✓ | ✗ | ✗ | ✗ |
| Free tier Usable without paying | Trial | ✓ | ✓ | ✓ |
| Recipe library & meal plans What to eat during your eating window | ✗ | Nutrition (Plus) | ✓ 4,500+ recipes | Coach tier |
| Community / social features Challenges, buddy system, feeds | ✗ | Limited | ✓ | Limited |
| Monthly subscription price Ongoing cost for full features | $4.99/mo | ~$5.83/mo ($69.99/yr, Zero Plus) |
~$6.67/mo ($79.99/yr, Fastic Plus) |
~$4.99/mo (BodyFast Coach) |
No other mainstream fasting app adjusts your protocol based on your menstrual cycle. Circafast knows that a 18:6 window on day 22 of a luteal phase is a terrible idea — and Zero, Fastic, and BodyFast don't even ask. We track your cycle phase and automatically shorten your fasting window in the luteal and menstrual phases when cortisol sensitivity peaks. The result: fewer energy crashes, better mood scores, and a protocol that actually fits your physiology — not just your calendar.
Zero asks you to track meals. Fastic asks you to scan food. BodyFast wants your weight and sleep data. Circafast asks three questions, once a day, for 30 seconds — energy, mood, difficulty — and the AI handles the rest. No food diary. No barcode scanner. No wearable required. The protocol updates itself overnight and sends you your new window by email. You wake up, eat your window, and check in tomorrow. That's it. If logging is why you abandoned your last fasting app, this is the fix.
Most AI fasting apps give you AI or nothing. Circafast has three modes: Full AI coaching (protocol adapts from your check-ins), Skip AI Today (keep tomorrow's window fixed, re-enable anytime), and Timer-only mode (pure fasting timer, no coaching at all). Every AI adjustment comes with a plain-language explanation of why. You can always see the reasoning, override it, or turn the whole thing off. The AI works for you — not the other way around.
First 100 founding members pay once and use forever. No monthly fees. No renewals.
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