If you’re gonna do it to do it, then you tough it out until 6pm tomorrow, eat a regular dinner with a 30 minute window and done at 6.30, having achieved it. Next day, do a 5.5 hour window starting at 12.30 and you are magically back on 18:6.
A 24 hour fast with IF is never actually a 24 hour fast. It’ll almost always be more becaue of sleep and timing.
So if you do a 24 hour, either expect it to be longer than that, or adjust the day before or after to have a longer eating window.
Nothing wrong with adjusting one of those days. It’s not an IF failure, it’s just readjusting things.
Sounds like you’re basically going to do 23:1 one day instead of your usual 18:6.
I don’t think the timing (hitting 24 hours as a magic number) really matters too much, unless you’re just testing out your fasting endurance or considering a move to 23:1/OMAD.
If you want to ‘skip a day’, skip a day, and then if you need to you can eat earlier (or split calories between breaking and your normal time) the following day. Then power through to your regular 18:6 the second day after your fast.
Sorry if this isn’t what you’re looking for, I’m just thinking that on the ‘24 hour fast’ day, all you have to do is make it to bed without eating that day and you’ve managed to skip a day’s worth of calories instead of just shifting them around.
That might be more useful in terms of supplementing your progress towards your goals than occasionally swapping in a 23:1.
I do 22:2 when on OMAD. That can extend to 23:1 when delayed at work. According to fasting phases we reach the last stage of autophagia after 16 hours.So I can’t really see a big advantage of fasting for 24 hours compared to 22-23 hours.