Prolonged fasting of 4-5 days in humans can induce autophagy, cell death, and regeneration.

“And the question that I had for you is, like, I've talked with Dr. Valter Longo, he was on the podcast, and he talked quite a bit about his research on prolonged fasting in both rodents and also in humans and how the prolonged fast, at least, in rodents is 48 hours, which in humans is around 4 days, 4 to 5 days. And that was able to very robustly, not only activate autophagy, but also cell death, and that was followed by a regeneration period.”