I started doing a 36 hour fast once a month for the gut reset and health benefits associated with it, I highly recommend it.
I will get real hungry from hour 21-24 or so, and then after that I'm good to go. I will do them on weekends/off days but also try to stay busy as well, so I'm not just holding down the couch wanting to eat or thinking about how hungry I am.
For me, I will feel the benefits normally a day or two after I'm done with the fast. I will also keep taking the normal supplements I do every other day (greens, beet powder, creatine, LMNT, etc.) and I'll also drink a little more water than I normally do on a normal day.