Common patterns
Patterns are written as fasting hours to eating hours: 16:8 is 16 hours without eating and 8 hours in which you eat. Other common windows are 13:11, 18:6 and 20:4, and some people fast for a full 24 hours. The eating window is whatever time is left in the day.
Timing a fast
A fast is best timed from the moment it started, not from a running counter, so the elapsed time is right even if your phone sleeps or the clocks change. One Fitness Hub stores the real start and end instants and works the elapsed time and the goal out from them.
Things to know
Fasting does not suit everyone. If you have a medical condition, take medication, or are unsure, ask a clinician before you start. This page is general information, not medical or dietary advice, and the fasting tools in the app are for adults 18 and over.
Fasting and your calorie budget
A fasting window changes when you eat, not how many calories the app counts. Your day's calorie budget is unaffected by a fast.
In One Fitness Hub
- Start a fast with a goal: 13:11, 16:8, 18:6, 20:4 or 24 h in one tap, or a custom whole number of hours from 1 to 72.
- A live card on the Day shows the running fast, End fast closes it, and Past fasts lists earlier ones, which you can edit or delete.
- Logging food inside a running fast asks whether to end the fast at that time or keep fasting, and nothing changes without your tap.
- You can ask to be notified when you reach your goal.
Common questions
Does a fast change my calorie target?
No. Fasting never changes the calorie budget, the week view or your estimated energy expenditure.
What happens if I eat during a fast?
The app asks whether to end the fast at that time or to keep fasting. Nothing changes until you choose.
Is fasting suitable for everyone?
No. Ask a clinician first if you have a medical condition or take medication. The app's fasting tools are for adults 18 and over.
Related terms
- Macros: Macros, short for macronutrients, are the three nutrients that provide calories: protein, carbohydrate and fat.
- TDEE: TDEE, or total daily energy expenditure, is an estimate of all the calories you use in a day, including resting energy and activity.
- BMR: BMR, or basal metabolic rate, is an estimate of the energy your body uses at rest, before any daily activity.
Keep reading
General education and fitness estimates, not medical or dietary advice. Figures from the app are informational and are not reviewed by a certified personal trainer.