How to use it
- Step 1Pick a schedule, from 12:12 to one meal a day.
- Step 2Set the time of your first meal.
- Step 3Enter your usual bedtime to check the gap between your last meal and sleep.
- Step 4Read your eating window and a 7-day meal schedule.
How the window is set
Eating hours = 24 − fasting hours. Your last meal = first meal + eating hours. On 16:8 with a first meal at 11:00 am, your window closes at 7:00 pm.
The tool flags a last meal within 2 hours of bed, since an earlier window may help reflux and sleep.
What the evidence shows
Studies that match calories usually find similar weight loss with fasting and regular calorie cutting. Fasting can help people who find a clear stop time easier than counting.
People with diabetes, especially on insulin or a sulfonylurea, people who are pregnant and anyone with an eating-disorder history should talk to a clinician first. On a GLP-1, read Fasting while on a GLP-1 before stacking the two.
Prefer a chart? See Fasting schedules: precomputed tables for common inputs.
More body and habits
Common questions
Which intermittent fasting schedule is best for beginners?
Many people start with 12:12 or 14:10 and move to 16:8 if it feels easy.
Can I drink coffee while fasting?
Black coffee, plain tea and water are usually fine. Milk, sugar and creamers add calories.
Does intermittent fasting work better than calorie counting?
Studies that match calories usually find similar results. It works if it helps you eat less overall.
Is it safe to fast on a GLP-1 medicine?
It can make it harder to get enough protein and fluids when appetite is already low. Talk to your prescriber first.