The only thing to watch with fasting is that too long, too often and your body will start pumping out adrenaline. Sometimes I can feel a bit jittery after about 18-20 hours, but I can handle it now because I know what to expect. But yes, the key to fasting is autophagy. Digestion hammers your resources, and not having to digest allows all sorts of things to heal.
I started out doing it every Monday. I'd fast the entire 24 hours. I slowly migrated to fasting daily.
Once a week for 24 hours is likely to be fine I think. Your exposure is short lived, and fasting over about 18 hours is the most beneficial for autophagy.