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HOME / FASTING / 4:3
Three 24 hour fasts a week, four ordinary days. Monday, Wednesday and Friday in Burn's version, which leaves every weekend clear.
One of the most demanding weekly patterns, graded Experienced.
Mon
24h
Tue
Rest
Wed
24h
Thu
Rest
Fri
24h
Sat
Rest
Sun
Rest
Each fast runs dinner to dinner, so no calendar day passes without a meal.
What it asks
Eat-Stop-Eat asks for two fasts and leaves five clear days. 4:3 adds a third, so the midweek fasts sit a single rest day apart. That is the whole difference, and it is a large one in practice.
One rest day between each midweek fast, then the weekend clear. Weekends stay yours, which is the reason this arrangement holds better than three consecutive days would.
Burn's highest difficulty grade, shared with Alternate Day. Come to this after you have run 24 hour fasts comfortably on a lighter pattern, not as a starting point.
Like Eat-Stop-Eat, this is a permanent shape for the week rather than a fixed-length course.
Making it work
Three fasting days create a large weekly deficit. Eating your way back through it on the four ordinary days is what turns this pattern into effort without result, so those days matter more here than on any lighter schedule.
Three 24 hour fasts a week means fewer meals to get protein into. Prioritize it on the days you eat rather than trying to catch up in one sitting.
A full day without food means no sodium arriving with meals, three times a week. Burn keeps sodium, potassium and magnesium in the Journal alongside your water.
Hard efforts want glycogen, and this schedule leaves four clear days for them. Put the demanding sessions there and keep fasting days easy.
Where it sits
All three use complete 24 hour fasts. The only variable is how many, and how much clear space sits between them.
TWO FASTS
Graded Intermediate. Five ordinary days, and clear days either side of each fast.
Read more →THREE FASTS
Graded Experienced. Four ordinary days, weekends clear, and one rest day between each midweek fast.
You are hereEVERY OTHER DAY
Also graded Experienced, and a two week course rather than an ongoing pattern. Four fasts in week one, with no clear run of ordinary days.
Read more →If three days a week is more than you want, 5:2 uses two reduced-calorie days instead of complete fasts. The 5:2 guide.
Running it in Burn
4:3 is one of Burn's 21 programs. Each fast is timed to the second, named by stage as it progresses, and kept in your history, so a month of this pattern is a record you can read rather than a rough impression.
Longest fast, total hours, completion rate and nine more. On a schedule this demanding, the record of what held is the useful part.
If Monday, Wednesday and Friday do not fit your week, Burn's three custom protocols let you set any fasting pattern and save it.
BEFORE YOU START
Do not use this schedule if you are pregnant or breastfeeding, have a history of eating disorders, or are under 18. Speak to your doctor first if you manage diabetes or take medication timed to meals, since three full days without food each week changes how those doses land. Stop and eat if you feel unwell, whatever the timer says.
WHERE THE EVIDENCE STANDS
Intermittent fasting patterns produce weight loss in controlled human trials, comparable to other approaches at matched intake. Which pattern a person can sustain matters more than which is theoretically optimal, and a more demanding schedule is not automatically a better one. Claims here are drawn from peer-reviewed research and traced in our evidence policy.
Burn times each one to the second, names every stage you reach, and keeps the record of the weeks that held.
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