No, it is exactly what it sounds like. I have a 12-hour window where I eat whatever I want every other day.
There are clinical studies to back up its effectiveness.
https://www.youtube.com/watch?v=Ihhj_VSKiTs
As you get older, your internal organs lose their capacity. When your stomach if full, almost all your energy goes to digesting food with nothing left over to heal things and produce hormones. Fasting releases the demand and allows your body to do the other things it needs to do.
https://drmindypelz.com/intermittent-fasting-for-hormones/
A three-day fast before chemotherapy increases its effectiveness and alleviates most of its side-effects.
When your stomach if full, almost all your energy goes to digesting food with nothing left over to heal things and produce hormones
So that's why all those old guys (which I guess includes me now) fall asleep on the couch after a holiday meal!