Some people are trying to build more muscle mass and they are not able to do it and this is why.
There is a lot that happens at the cellular level. It takes insulin to act as a key to unlock the door of the cell and allow amino acids to go into the cell to be converted to skeletal muscle protein.
Why? First, intermittent fasting triggers a hormone called growth hormone. Growth hormone is the main hormone that spares muscle protein breakdown in your body. It protects it.
Cortisol, the stress hormone, and insulin both cause destruction of your muscles. So stress, eating sugar, having instant resistance, being a diabetic destroys your muscles. Forty hours of fasting did not trigger any breakdown of skeletal muscle. I did not find the study he was talking about but I found this one, SIX things I have Learnt from forty-hour Fasting https://annfoweraker.com/tag/40-hour-fasting/