16:8 Fasting Schedule: How to Plan Your 16-Hour Fast
16:8 fasting is the most popular intermittent fasting protocol — fast for 16 hours, eat within an 8-hour window. It's beginner-friendly because the fast covers the time you're already sleeping, and most people land in mild ketosis right at the end of the fasting window.
How 16:8 works
Pick an 8-hour eating window — most people use 12:00–20:00 or 11:00–19:00. Outside that window, water, black coffee, plain tea, and electrolytes are fine. Inside the window, eat normally without overcompensating. Aim for at least one protein-forward meal and don't skip vegetables.
A sample day
- 07:00Wake up. Water + black coffee. No food.
- 11:00Continue water + electrolytes if needed.
- 12:00Break fast: protein + fiber + healthy fat (e.g., eggs, avocado, greens).
- 15:30Optional snack or second meal.
- 19:30Last bite — close the eating window.
- 20:00–07:00Fasting window. Water only.
What happens in your body
Physiological milestones reached during a 16-hour fast.
- h4
Blood sugar normalizes
Insulin drops back to baseline as your last meal finishes digesting.
- h8
Glycogen burning begins
Your liver starts releasing stored glycogen to keep blood glucose steady.
- h12
Glycogen depletion
Liver glycogen runs low; the body shifts toward fat for fuel.
- h14
Fat burning accelerates
Lipolysis ramps up — stored triglycerides break down into free fatty acids.
- h16
Mild ketosis starts
The liver begins producing ketones from fatty acids. Mental clarity often improves here.
What to eat
Inside your window, prioritize whole foods: a palm of protein per meal, two fistfuls of vegetables, a thumb of fat, a cupped hand of carbohydrate. Skip ultra-processed snacks — they spike insulin and undo much of the benefit. Stay hydrated outside the window with water, black coffee, plain tea.
How to break the fast
- Eggs with avocado and leafy greens
- Greek yogurt with berries and walnuts
- Salmon with roasted vegetables
- Lentil soup with a side of roasted chicken
Who it's for
- • Beginners trying intermittent fasting for the first time
- • Anyone with a regular daytime schedule
- • People targeting body composition and steady energy without aggressive restriction
- • Coffee and tea drinkers (both are allowed during the fast)
Benefits
- • Hits mild ketosis by the end of most fasts
- • Natural overlap with sleep makes it sustainable long-term
- • Improves insulin sensitivity within 4–8 weeks for most people
- • Few electrolyte concerns at this length
Risks & cautions
- • Not appropriate for people with a history of eating disorders
- • Pregnant or breastfeeding people should consult their doctor first
- • Type 1 diabetes and certain medications need clinical supervision
Frequently asked questions
Does coffee break a 16:8 fast?
Will I lose muscle on 16:8 fasting?
Can I exercise while fasting on a 16:8 schedule?
How long until 16:8 starts working?
Is it OK to do 16:8 every day?
Related schedules
Track your 16:8 fast in QoFast
Live timer, milestone tracking, water and electrolyte logging — free on iOS & Android.
