A great study just passed to me from the illustrious Ben Bikman.
Study looking at how insulin inhibits autophagy …….Except in exercise.
“In conclusion, one hour of cycling exercise increases phosphorylation of ATG14 at Ser29 in a pattern that mirrors ULK1 phosphorylation at Ser555 (activating site), suggesting that ULK1 serves as an upstream kinase for ATG14 in human skeletal muscle. These effects were independent of high and low insulin levels during exercise.”
Essentially what this says is that exercise causes autophagy regardless of the level of circulating insulin.
It still remains true today that the only real way to measure autophagy in humans has been with exercise and it can be measured in hours. There has yet to be a study in humans measuring autophagy from fasting to the extent it can be measured in just an hour of exercise. Even when insulin might be high.
From what I can tell, Ben’s opinion on autophagy is that it is running when insulin is low and that is happening when you are in ketosis. I don’t think he tells people not to fast but I don’t think he does it personally. He discusses this in this Podcast.
My opinion is that those that are seeking autophagy need not worry so much about fasting and just keep insulin low.
Better yet, seek it through something healthy, like exercise.
Here is another study showing autophagy from exercise regardless of nutritional status.
“Taking into account AMPK-dependent autophagy activation, these findings support the notion that HI is the most potent way to increase autophagic flux during cycling exercise in human skeletal muscle, independent of nutritional condition.“