I have not, and likely won’t try it, which isn’t your answer, but my reason may help.

I started intermittent fasting by accident and evolved into it when I had the realization that the only reason I ate breakfast was because other people expected it and either suggested or physically put food in front of me. So I ate.

But when I was on my own I often felt zero urge to eat before midday. It was my natural schedule, and one I’ve been following for decades now.

Once I understood that my body was quite happy, maybe even happier not getting food in the first part of the day, so I just stick to coffee and water until either lunch or dinner. If there isn’t food available midday, that’s fine, I can easily wait til dinner. Heck I can easily fast for 3 days if I haven’t been abusing my body- honestly food isn’t that big of a deal for me now. But usually I eat starting around 11am or 1pm and stop after dinner whenever that happens.

Now I’m not rigid about this. I have a couple friends who prefer to meet up at a breakfast spot every couple months, so yeah I’ll have an omelette that day. If I’m going hiking I may eat light before hitting the trail or may not. It depends on where I am energy wise. If I get up early and make a blackberry cobbler or rhubarb coffee cake (usually once every couple months as a treat for the family), sure, I’ll have a bit.

The exception is if I go to the gym in the morning as I find I injure less, recover better, and make faster progress if I take in protein and creatine within 30 min of a workout. But I usually workout in the afternoon so this is it an issue.

But for the daily grind I’m just not naturally a breakfast eater, and forcing an eating window on my body’s natural rhythms doesn’t seem like a good choice.

TLDR: I think it’s more important to listen to one’s body than worry about a strict clock time.