Your body knows not to start with important organs. It does take a while before it leads to damage (measurable shortened lifespan or lowered health / quality of life). If you have fat reserves, the most important thing is covering the nutrients our body can’t produce (salts, some vitamins, etc)to avoid actual damage if fasting for a week or more.
Autophagy appears to start after not eating for a single day. Your body goes into emergency mode quite fast.
Your body knows not to start with important organs. It does take a while before it leads to damage (measurable shortened lifespan or lowered health / quality of life). If you have fat reserves, the most important thing is covering the nutrients our body can’t produce (salts, some vitamins, etc)to avoid actual damage if fasting for a week or more.
https://link.springer.com/article/10.1007/s11357-025-02035-4