Which fasting schedule is right for you?
14:10
A late breakfast and an early dinner. Easy to keep up, a good first step.
16:8
Skip breakfast, eat from noon to 8 pm. The most studied and most common method.
18:6
A shorter window, for example 13:00 to 19:00. Two meals and a snack.
20:4 and OMAD
One or two big meals. Hard to fit enough protein, best for experienced fasters.
Do calories still count when you fast?
Yes. A 2020 trial in JAMA Internal Medicine found 16:8 alone led to little weight loss, and a 2022 trial in the New England Journal of Medicine found time-restricted eating plus calorie counting worked about as well as calorie counting alone. Fasting helps because a shorter window makes it easier to eat less.
So set a calorie target first, then use the window to hit it. If you want to log meals without an app, myCalCoach on Telegram estimates calories from a photo and tells you what's left before your window closes. Protein matters more on short windows, so check your number with the protein calculator.
Common questions
What is the 16:8 method?
You fast for 16 hours and eat within an 8 hour window each day, for example from 12:00 to 20:00. Most of the fast happens while you sleep.
Does intermittent fasting work for weight loss?
It works when it helps you eat fewer calories. Trials comparing time-restricted eating with ordinary calorie restriction at the same intake found similar weight loss. The window is a tool to make the deficit easier, not a separate effect.
What can I drink while fasting?
Water, black coffee, plain tea and other zero-calorie drinks are fine for most people. Milk, juice and sugary drinks break the fast.
Which fasting schedule should I start with?
Start with 14:10 or 16:8. Both fit around a normal day and are the most studied. Stricter windows like 20:4 or one meal a day make it harder to eat enough protein.
Who should not do intermittent fasting?
People who are pregnant or breastfeeding, under 18, have a history of eating disorders, or take insulin or other glucose-lowering drugs should talk to a doctor first.
Other free calculators
Sources
- Lowe DA, et al. Effects of time-restricted eating on weight loss and other metabolic parameters: the TREAT randomized clinical trial. JAMA Intern Med. 2020;180(11):1491-1499.
- Liu D, et al. Calorie restriction with or without time-restricted eating in weight loss. N Engl J Med. 2022;386(16):1495-1504.
- de Cabo R, Mattson MP. Effects of intermittent fasting on health, aging, and disease. N Engl J Med. 2019;381(26):2541-2551.
This calculator gives general guidance and is not medical advice.