Fasting.
I don't follow anything in particular. I mostly: 1) Breakfast is green tea, no sugar/honey/whatever. 2) Maybe I eat lunch, maybe I don't. 3) Maybe I eat dinner, maybe I don't.
And I try to avoid sugars explicitly, carbs mostly (But I might eat a sandwich. But if pizza, I scrape off the toppings to eat. No fries, chips, etc).
Overall, being keto seems to make ignoring meals easier.
In the past, I've taken electrolytes to counter the headaches that sometimes come with fasting (see snake juice on Amazon). It tastes terrible, though.
When I've been more structured about it, I used the guidelines here:
https://www.reddit.com/r/fasting/
At this point in time, I'm not fasting more than 1 day (so OMAD like). And I've cranked up my lower intensity exercise (walking, biking) and still swimming. Harder without carbs to do high intensity exercise, imho.
It's not me, it's someone else.