Fasting tool
Fasting Schedule Calculator
Choose a fasting plan and when you finish eating. The calculator shows when your fast ends and roughly when each of the five stages Step Step follows usually begins. The stage names and descriptions are the same ones you see in the app.
These stages are a general guide, not a measurement. What happens and when varies from person to person and day to day. Step Step is educational and is not medical advice, so talk to a doctor before making big changes, especially if you are pregnant, take medication, or have a health condition.
How this works
Landmarks, not measurements
The stage hours (4, 12, 16 and 24) are conventional landmarks used in the app, not readings from your body. When glycogen runs low and ketone production picks up depends on your last meal, how active you are and how used to fasting you are. Treat the times as a rough map, not a schedule your body keeps.
Choosing a plan
If you are new to fasting, a 12 or 13 hour overnight fast is the gentlest start, because most of it happens while you sleep. 16:8 is the most popular routine. Longer fasts are worth working up to slowly, and they are not for everyone.
When not to fast
Fasting is not suitable if you are pregnant or breastfeeding, under 18, or have a history of eating disorders. If you have diabetes or take medicine that affects your blood sugar or blood pressure, talk to your doctor first. Stop and eat if you feel faint or unwell.
Read more about when not to fast
References
- de Cabo, R. & Mattson, M.P. (2019). Effects of Intermittent Fasting on Health, Aging, and Disease. New England Journal of Medicine, 381(26), 2541 to 2551. Read the abstract
- Cahill, G.F. (2006). Fuel metabolism in starvation. Annual Review of Nutrition, 26, 1 to 22. Read the abstract
For healthy adults. This is general information, not medical advice.