Set your eating window.
Choose a 12:12, 14:10 or 16:8 pattern and the time of your first meal, and the tool draws your eating window on a 24 hour clock with the last meal, the main meal and the fasting hours in between. You get a one-line plan you can follow tomorrow, three practical notes, a plain word on who should not fast, and a card to save or share.
Pick a pattern, set your first meal.
The clock draws the hours you eat and the hours you do not. Everything below follows from three choices.
Eat between 08:00 and 16:00, then water, tea or coffee without milk and sugar until 08:00.
An early window like this one is where trials found the small gains in blood pressure and insulin sensitivity.
Three notes that matter more than the hours
- Front-load protein. Put 25 to 30 g of protein in the first meal; a shorter day makes the daily target harder to reach.
- Keep the window consistent. Open and close within 1 hour of the same times every day, weekends included. Regularity is what the trials measured.
- Do not compensate by overeating. The window only helps if the day's total goes down or stays the same.
Fasting patterns are not for everyone. Talk to a doctor first, or skip them, if any of these apply:
- pregnancy and breastfeeding
- diabetes treated with medication
- a history of eating disorders
- under 18 years of age
- underweight, a BMI below 18.5 kg/m²
How it works.
- Choose 12:12, 14:10 or 16:8 and enter the time of your first meal; 08:00 is the default.
- Read the clock: the green arc is your eating window, the two markers are first and last meal, the gold one is your main meal.
- Follow the one-line plan for a week, keep the window within 1 hour of the same times each day, then save or share the card.
What the trials show
Time-restricted eating means all food lands inside a fixed window, usually 8 to 10 hours, with nothing but water, tea or coffee without milk and sugar outside it. In most trials of 8 to 12 weeks the scale moves by about 1 to 4 percent of body weight, mostly because people who stop eating at 16:00 or 18:00 drop the late snacks and end up 300 to 500 kcal a day short. The largest test so far, a 12 month trial in the New England Journal of Medicine in 2022, gave 139 adults with obesity the same calorie target and let half of them eat only between 08:00 and 16:00. The 16:8 group lost 8.0 kg, the other group 6.3 kg, and the gap was not significant. The window helped people eat less; it added nothing on top of eating less. The guide on time-restricted eating goes through the trials one by one.
Why the clock matters more than the count
Where the window sits seems to matter. A small crossover trial from 2018 put 8 men with prediabetes on a 6 hour window that closed by 15:00; after 5 weeks their insulin sensitivity had improved and systolic blood pressure had fallen by about 11 mmHg, with no weight loss at all. A 12 week trial with a late window of 12:00 to 20:00 found no advantage over eating freely. Consistency counts too: a window that shifts by 3 hours at weekends gives up much of the effect, so keep it within 1 hour. Late windows push dinner towards bed, and the 7 to 9 hours of sleep adults need come easier with 2 to 3 hours between the last meal and lights out. What is on the plate still decides most of the outcome, and the daily sugar limit of 30 g does not pause because the clock says fasting.
What this tool is not
It is a planner, not a diet and not a medical device. It turns a pattern and a first meal into clock times and knows nothing about your weight, medicines or blood sugar. The idea that fasting extends life comes from mice, where feeding within a fixed window stretched lifespan by 10 to 35 percent in a 2022 study; no human trial shows that, and the honest measure for now is healthspan, the years lived in good health. Some people should not fast without medical advice at all: during pregnancy and breastfeeding, with diabetes treated by insulin or other glucose-lowering medication, after an eating disorder, under 18, or when underweight. If that is you, talk to a doctor before you change when you eat.
Frequently asked.
Does coffee break the fast?
Water, plain tea and black coffee carry close to 0 kcal and keep the fast. Milk, sugar, juice, a latte at around 150 kcal or a handful of nuts all count as eating, so they belong inside the window.
Which pattern should I start with?
12:12 for the first 1 to 2 weeks, which for most people means nothing after dinner and breakfast at the usual time. Move to 14:10 once that feels normal, and to 16:8 only if it fits your work, your training and your sleep.
Is an early window better than a late one?
The trials with the best readings for blood pressure and insulin closed the window by 15:00 to 18:00. A late window of 12:00 to 20:00 tested over 12 weeks showed no advantage over eating freely, so an earlier first meal is the better bet if your day allows it.
Will I lose weight with a 16:8 window?
Usually 1 to 4 percent over 8 to 12 weeks, because the shorter day removes 300 to 500 kcal of snacking. If you eat the same amount inside the window, the scale does not move, which is what the 2022 trial found against calorie restriction alone.
Can I train during the fasting hours?
A walk or an easy session is fine for most people. Put hard training inside the window or within 1 to 2 hours of its start, so the meal after it delivers the 20 to 30 g of protein the muscles need.
What does the tool save?
Only the pattern, the first meal and the main meal position, stored in your own browser so the clock shows your window next time. Nothing is sent anywhere.
Guides behind this tool
Longevity
Healthspan versus lifespan: the years that count
Health
How much sleep adults really need: 7 to 9 hours, and whyMore tools
This planner turns a pattern and a first meal into clock times; it is not a diet plan, a diagnosis or medical advice, and it knows nothing about your weight, medicines or blood sugar. People who are pregnant or breastfeeding, take medication for diabetes, have a history of eating disorders, are under 18 or underweight should not fast without talking to a doctor. This page is for general information and does not replace medical advice.