Fasting and fasting-mimicking diets can cause organs to shrink and re-grow during refeeding, potentially involving cell death and stem cell activation.

“doing a prolonged fast and or in some cases the fasting mimicking diet causes this massive shrinking of organs where now he doesn't know how much of it's due to cell size decreasing versus apoptosis he does know a puppet apoptosis is occurring and he has showed that in multiple publications like there's a massive induction of apoptosis after a prolonged fest and you know which makes sense because it's a very strong stress and then after during the refeeding phase their organs basically come back they come back they grow regrow and presumably selectively repopulate yes so he's shown that these stem cells get activated”

“The most powerful way, particularly if it's prolonged, to shrink a system, let's say, make the liver a lot smaller, make all these organs a lot smaller, the immune system, and then regenerate it, right?”

“And he was talking about how this prolonged fasting in mice, which is about 48 hours or translates to like four days in humans which is quite a long fast, but was able to just very robustly clear away damaged cells, presumably senescent cells well. Also caused cellular death, but followed by a massive and robust increase in stem cell proliferation sort of replenishing the population.”

“mice, which is about 48 hours or translates to like four days in humans which is quite a long fast, but was able to just very robustly clear away damaged cells, presumably senescent cells well. Also caused cellular death, but followed by a massive and robust increase in stem cell proliferation sort of replenishing the population.”

“So the organs will be smaller, and at the end of the days of fasting-mimicking diet, and then you refeed and of course they go back to the normal level, right? So there is really, there is this shrinking and re-expanding effect.”

“And I think that you...maybe you want to talk about this, the...what... Yes. So in mice for example, if you look”

“So we suspect that there are these fasting-dependent, depletion of both intracellular components, you know, autophagy, and cellular components, and then we've shown the stem cell to be activated, and then the stem cell during the refeeding part.”

“doing doing a prolonged fast can basically cause organs to shrink inside of animals during the fasting phase and that is due to a variety of factors one cell size is shrinking two cells are dying and what vaulter is shown is that preferentially damaged old cells die and this then can basically during the refeeding phase which I think now that was a question I missed when you're breaking your fast the refeeding phase causes causes stem cells to proliferate and to replace all those cells that were lost and so that the organs that shrunk regrow and their regrowing with healthy new young cells so it's really this amazing rejuvenation process that seems to be hard encoded in our genes and activated just by not eating”