HOME / FASTING / CUSTOM SCHEDULES
Set any fast length and any eating window, name it, and save it. Burn holds three custom protocols alongside the nine built-in schedules.
For the weeks that are not the same every day: a longer weekday fast, a shorter one around training, something different on a Sunday.
What a protocol holds
That is the whole thing. The name is what makes it usable, because a protocol called Training day tells you when to pick it and 14:10 does not.
17:7
WEEKDAY
Seventeen hours sits between 16:8 and 18:6, deep into Fat Mobilisation without reaching Ketosis Entry. Nothing in the built-in nine lands there.
14:10
TRAINING DAY
Hard efforts want glycogen, so a ten hour window gives you room to eat before and after the session. Saved as its own protocol, it is one tap rather than a decision.
20:4
SUNDAY RESET
A single day that goes further than the rest, on the day you have least on. Twenty hours reaches two hours into Ketosis Entry.
The three protocols above are the ones shown in Burn's Custom Protocols sheet. Yours can be any lengths you choose.
Why three
Three named protocols covers a normal shape, an exception, and one day that is different again, without turning the picker into a list you have to read.
Each protocol has an edit and a delete control, so a slot is never spent. Change the length, rename it, or clear it and write a different one.
Custom protocols do not replace the standard schedules. A saved protocol is there for the day that calls for it, and the built-in nine are unchanged.
Every fast lands in the same record regardless of which protocol started it. Completions, streaks and twelve personal records all count it.
Choosing your own length
A custom length is worth setting deliberately rather than by round number. These are the boundaries the stages open on.
14h
Fat Mobilisation opens. The first boundary worth aiming at.
18h
Ketosis Entry opens. Setting 17h stops just short of it.
24h
Fat Burning opens. Past here, electrolytes stop being optional.
48h
Deep Ketosis opens. Plan a fast this long with a doctor.
The first day runs at one scale and the 24-48h band is compressed against it at three to one. Nothing in the biology switches on at a stated hour; Burn draws each line because a timer has to draw one.
A custom protocol still has a target. If you would rather start the clock and decide later, Burn's Flexi plan runs open-ended and names each stage as you reach it, with no goal to fall short of.
Open-ended fasting →Speak to your doctor before starting if you are pregnant or breastfeeding, have a history of eating disorders, manage diabetes, take medication timed to meals, or are under 18. Fasts of three days or more should be planned with a doctor, including how you break them.
Three named protocols, any lengths you choose, and one history that counts them all.
Download free on the App StoreiPhone, iPad, and Apple Watch. Requires iOS 18 or watchOS 11.
