Autophagy kicks in about 18 hours in. IF is practiced a multitude of ways. Some do 20:4 some do 16:8. OMAD usually means 23:1. It’s all about how long you fast for Autophagy.
My IF schedule which isn’t easy but has worked wonders for me:
Mon 20:4Tuesday 20:4Wed no food at all eat again Thursday evening results In a weekly 44 hour fast which I do specifically for the benefits of autophagyThursday see aboveFriday 20:4Sat and Sun 16:8