An Intermittent Fasting companion application for iOS.
FastFlex is the iOS app I created, because I couldn’t find what I needed to support my Intermittent Fasting routine. The app is currently available on the Apple App Store at the following link: https://apps.apple.com/us/app/fastflex/id6747295490?platform=iphone.
Privacy Notice: This app does not collect or store personal identifiers of any type.
Choosing the best intermittent fasting (IF) option depends on your current lifestyle, goals, health status, and experience level. Here’s a structured way to decide where to start:
1. Define Your Goal First
Different fasting windows fit different purposes:
| Goal | Best Starting Windows | Why |
| Weight loss | 14/10 → 16/8 | Creates a moderate calorie deficit without extreme restriction. |
| Metabolic health / insulin sensitivity | 14/10 → 16/8 | Improves blood sugar control and reduces snacking frequency. |
| Longevity & cellular repair (autophagy) | 16/8 → 18/6 → OMAD | Longer fasts trigger more cellular cleanup processes. |
| Muscle preservation & performance | 12/12 → 14/10 | Allows sufficient feeding time for protein intake and recovery. |
2. Start Small and Build Up
For most people, jumping straight into 18/6 or OMAD (one meal a day) can backfire — fatigue, headaches, and binge-eating are common. Instead:
- Beginner-friendly start: 12/12 → 12 hours eating, 12 fasting.
Good for easing your body into fat-burning. - Step up gradually: After 1-2 weeks, move to 14/10.
- Then progress: Try 16/8 if you want better results and feel comfortable.
This “progressive overload” approach works the same way you’d ramp up gym training — sustainable and easier on your metabolism.
3. Consider Your Lifestyle & Schedule
Your work hours, workouts, and sleep patterns matter:
- Morning workout people: Avoid starting with long fasts unless you can handle training on an empty stomach.
- Night owls: A later eating window like 1 PM–9 PM works better.
- Healthcare shift workers (like you’ve managed teams of): You’ll want flexibility — maybe start with 12/12 or 14/10 until your body adjusts.
4. Factor in Health Conditions
- Diabetes / hypoglycemia risk: Start conservatively (12/12 or 14/10) and consult a doctor first.
- Thyroid or adrenal issues: Extreme fasting may worsen fatigue — shorter windows are safer.
- Athletes or heavy lifters: Make sure your eating window supports your training.
5. Test, Track, and Tweak
- Use an app (e.g., Zero, Fastient, or your own FastFlex app 😉) to track fasting windows.
- Watch for biofeedback:
- Energy levels: Do you feel sharper or sluggish?
- Sleep quality: Poor sleep often means your fasting window is too aggressive.
- Hunger cues: Constant cravings mean scale back and lengthen your eating window.
6. My Recommended Approach for Most Beginners
- Weeks 1-2: Start with 12/12 → No eating after dinner.
- Weeks 3-4: Move to 14/10 if energy feels stable.
- Weeks 5+: Try 16/8 for better metabolic and weight benefits.
- Beyond: Experiment with 18/6 or occasional OMAD, but only if it aligns with your goals and feels sustainable.
Takeaway
Start easy, listen to your body, and let the window find you.
Consistency beats aggression in intermittent fasting.
