16:8 Intermittent Fasting
Fast for 16 hours, eat within 8. It's the most popular fasting method because it's effective and easy to fit around a normal day.
How the 16:8 method works
With 16:8, you split your day into a 16-hour fasting window and an 8-hour eating window. Most of the fasting happens while you sleep. A common approach: finish dinner by 8:00 PM, skip breakfast, and eat again at noon. During the fast you drink only water, black coffee, or plain tea.
A simple 16:8 schedule
- 8:00 PM — finish your last meal, fast begins
- 8:00 PM – 12:00 PM — fasting window (water, black coffee, tea)
- 12:00 PM — break your fast with your first meal
- 12:00 PM – 8:00 PM — eating window (typically 2–3 meals)
What to expect
Around the 12-hour mark your body starts shifting from burning glucose to burning stored fat, and by roughly 16 hours ketone production picks up. The first week can bring some hunger as your body adjusts — this usually fades. Learn more in the full 16:8 guide.
Calculate your 16:8 window
Enter the time you finish eating and see exactly when your 16-hour fast ends.
Your fasting plan
Tip: this is usually the time you finish your last meal.
Fast starts
8:00 PM
Fast ends — you can eat
12:00 PM (next day)
Eating window closes
8:00 PM (next day)
What happens during your fast
Blood sugar settles
~4h · 12:00 AM (next day)
Digestion wraps up and insulin starts to fall.
Fat burning begins
~12h · 8:00 AM (next day)
Glycogen runs low and your body turns to stored fat.
Ketosis ramps up
~16h · 12:00 PM (next day)
Ketone production increases as fat becomes the main fuel.
Timings are approximate and vary by person, activity, and last meal. This is educational, not medical advice.
Track this fast automatically
The free Fasting Tracker app runs this timer live and shows your stages in real time.
16:8 fasting FAQs
What is 16:8 intermittent fasting?
16:8 intermittent fasting means you fast for 16 hours each day and eat all your meals within an 8-hour window. For most people the simplest way to do it is to skip breakfast, eat between noon and 8:00 PM, and fast overnight.
Can you drink coffee during a 16:8 fast?
Yes. Black coffee, plain tea, and water don't break a fast because they contain essentially no calories. Avoid adding sugar, milk, or cream during your fasting window.
How long until 16:8 shows results?
It varies. Many people notice changes in appetite and energy within the first week or two, while weight changes depend on your overall calorie intake and activity. Consistency over several weeks matters more than any single day.
This page is educational and not medical advice. Talk to your doctor before starting if you have a health condition, are pregnant or breastfeeding, or have a history of disordered eating.