Autophagy keeps getting brought up with such pseudoscientific bullshit explanations that I can't help but see it as snake oil. Furthermore, depending on who is describing it, the window for autophagy to kick in is anywhere from 8-48+ hours.
There is a lot of "bro-science" out there concerning autophagy for sure, but it is definitely a thing. Yoshinori Ohsumi won the Nobel Prize in Physiology or Medicine in 2016 for "his discoveries of mechanisms for autophagy" (https://www.nobelprize.org/prizes/medicine/2016/summary/).
Ohsumi's research into the mechanics of autophagy doesn't seem to have much to do with the broscience around autophagy.
In other words, the question isn't whether autophagy exists. The question is over whether fanatical "one-weird-trick" claims about autophagy are true and, further, what the impact actually is and compared to what.
For example, autophagy is happening all the time, not just during during starvation. And it hasn't been demonstrated that fasting for 3 days to increase autophagy levels has a net benefit versus eating a nutrient-rich diet during that timeframe.
Instead we just get vague but lofty claims in forum posts.
I don't know what science you need to understand a system that is constantly active and is never fully allowed to rest will develop dysfunction. Anyway, as the sibling reply says, there is plenty of reputable research available to satisfy your curiosity if you wish.
