The rule: your last bite
A fast is usually counted from the last time you ate or drank anything with calories to your next first meal. Counting from when a meal started, or from bedtime, overstates your fast.
Tricky cases
| Situation | Start time |
|---|---|
| Dinner 20:00–21:00 | 21:00 |
| A few pieces of fruit at 21:30 | 21:30 |
| Black coffee at 22:00 | No change |
| A glass of milk at 23:00 | Restart at 23:00 (decide your rule in advance) |
| Next morning’s first drink is a latte | End the fast when you drink it |
For drinks such as black coffee and tea, see does black coffee break a fast.
Adjusting times in the app
Forgot? Start now anyway
If you forgot to tap start, tap "Start Fasting" as soon as you remember. You cannot change the start time of a fast in progress, but you can fix it once it ends.
Use the pencil in History
After stopping the fast, open the History tab and tap the pencil (Adjust times) on the record. You can edit start date, start time, end date, end time and target duration (hours). The end time must be after the start time to save.
Tapped stop by mistake? Same approach
An accidentally stopped fast cannot be resumed. Start a new fast as a placeholder, and when you actually finish, fix the earlier record’s end time and delete the placeholder.
Edited values feed straight into Average duration, Goal success rate and the streak in Stats.
FAQ
I forgot to log yesterday entirely. Can I add it?
The current version cannot add a past fast from scratch; you can only edit the times of recorded fasts.
What date is used when a fast crosses midnight?
History shows the start date, and the streak counts the date a goal-reaching fast ended.
Intermittent Fasting Timer: 16:8 Diet & Fasting Log
No sign-up, works offline, and your fasting log stays on your phone. Free on Android, in English and Korean.