The next podcast I listened to on Drive was #18(Sep 10, 2018, Dr Richard Isaacson, M.D. Alzheimer's prevention Cornell). I am continually on the radar for anyone citing new research or theories on balancing/homeostasis with fasting, autophagy, ketosis and maintaining weight. Most seem to stop just short of going into these topics deeply. My takeaway from this listen: Dr. Isaacson referred to research that documented 16 hour fasting daily is better for Apoe4 than 12 hour fasting. And it stops there not mentioning other possible variations of plans(i.e. longer fasts and 2-3 day breaks, 24 hr daily fast for several months out of the year, etc.) Bredesen and Gundry have suggested 16 hour daily fast for ApoE4's also. This is the first I have heard of research documenting it. Oh course the question still hangs out there....how long and often should one stay in autophagy and ketosis? I also wonder if it matters what level of ketosis(using breath meter) one is maintaining. Generally I stay in the range of .05-1.5. When I have too manycarbs or not enough healthy fats and fall out of ketosis, it usually takes a couple of days with close attention to no fruits, dairy, grains, 3oz daily portions of seafood or shellfish, and eliminating resistant starches to get back to ketosis.