Sample 20:4 schedules
| Option | Eating window | Fast |
|---|---|---|
| Start at 7:00 am | 7:00 am to 11:00 am | 20 hours |
| Start at 8:00 am | 8:00 am to 12:00 pm | 20 hours |
| Start at 9:00 am | 9:00 am to 1:00 pm | 20 hours |
| Start at 10:00 am | 10:00 am to 2:00 pm | 20 hours |
| Start at 11:00 am | 11:00 am to 3:00 pm | 20 hours |
| Start at 12:00 pm | 12:00 pm to 4:00 pm | 20 hours |
Who should be careful
Talk to a clinician first if you take insulin or a sulfonylurea, are pregnant or breastfeeding, have an eating-disorder history, or take a GLP-1 medicine and already eat very little. On a GLP-1, protein targets get harder in a short window: fasting and GLP-1s.
How to use it
- Enter your numbers. Switch between US and metric units at any time.
- Results update as you type, and the formula is shown so you can check it.
- Copy the link, save the plan on this device, or print it for your next appointment.
These are estimates, not a diagnosis. A clinician can account for your health history and medicines.
Other schedules
Common questions
How does 20:4 fasting work?
You fast for 20 hours and eat within a 4-hour window each day, for example 10:00 am to 2:00 pm.
Does 20:4 fasting help weight loss?
It can, mostly by making it easier to eat less. Studies generally find results similar to plain calorie cutting.
Clinician review pending. Drafted from primary sources and waiting for sign-off by a registered dietitian before launch. Every number is checked against its source. Drug facts are re-checked quarterly, prices monthly and whenever a label changes. How we review · Report an error