Once I finished the 35 days fast, I started going to the gym. Body fat dropped from ~24% to ~10% on the fast and now up to ~18% after 2 month bulk, so I added more muscle mass, but I had a lot of work as well so I was not able to hit the gym as often as I'd like and I had extra calories.

The biggest surprise to me was I was way more focused and attentive but I couldn't sleep much (sometimes 4 hours max). And at some point I got "keto rash" but it faded away eventually.

I think if you do the fast and then break the fast with stricker caloric diet and more protein you can gain lean muscle mass, but I got worried when I reached 58 kilos as people started pointing out how skinny I got..so I started bulking up again..