 So fasting or getting into that fat-burning mode or that autophagy happens the second after 10 to 12 hours. Let's just say 12 hours. So a typical fast would be 16 hours long or a fat-burning mode for four hours each and every day. Okay, that's the general rule of thumb. Some people do day on, day off. Some people do 24-hour fast. Some people do OMAD, which is one meal a day.