LightnFast Support

LightnFast is a focused intermittent fasting tracker for iPhone and Apple Watch. For help, bug reports, or feedback, email ysh@yishanhe.net.

When reporting a problem, include your iPhone model, iOS version, and a short description of what happened. Do not include private health information.

Frequently Asked Questions

Is LightnFast a subscription?

The core iPhone experience is free. Pro is an auto-renewable subscription available monthly or yearly. US prices are $1.99 per month or $9.99 per year. Pro includes widgets, optional Apple Health experiences, and the Apple Watch companion.

How do I restore Pro?

Open the Pro purchase screen and tap Restore Purchases. StoreKit checks purchases associated with your Apple Account; you are not charged again.

How do I manage or cancel Pro?

Open the subscription settings in LightnFast and choose Manage subscription, or manage the subscription through your Apple Account settings.

Can I use LightnFast on Apple Watch?

Pro includes the paired Apple Watch app and complications. Start or end a fast on Watch and view its current status. Purchase or restore Pro on your iPhone.

How do I connect Apple Health?

Open LightnFast’s Apple Health settings, choose Connect Apple Health, then select the data you want to share. LightnFast can read supported weight, body composition, and sleep information and can save supported weight and water entries when you ask it to.

Health access is optional. Weight and body-composition reads stay on device. A Health-suggested bedtime that you save becomes part of your daily record and can sync if you enable iCloud record sync.

Does LightnFast write fasts to Apple Health?

No. Apple Health has no official intermittent-fasting category. LightnFast does not disguise fasts as workouts, mindful sessions, or meals.

How do I export my data?

Go to Settings > Export data. LightnFast creates CSV files that you can save or share using the iOS share sheet.

What syncs through iCloud?

If you enable iCloud record sync, fasting history, plans, goals, daily results, saved bedtime entries, and notes can sync through your private iCloud account. The choice takes effect the next time you open the app. Notification preferences sync separately.

Records that have not synced can be permanently lost if you delete the app or lose the iPhone. Sync is not a historical backup. CSV exports provide a separate copy you can save or share, but LightnFast cannot import them.

What do fasting stages mean?

Stages are informational estimates based on elapsed time and published research. They do not measure your metabolism, diagnose a condition, or provide medical advice. Actual timing varies by person and circumstance.

Need more help?

Email ysh@yishanhe.net. The developer is Shanhe Yi.