You on gear?
Sounds good but off gear I'd be scared lof osing the little bit of mass that stayed lol.
I'm on trt, you don't lose muscle, you lose pure body fat, when fasting you are literally living off your fat stores. It's the best bio hack of all time, you don't have to burn yourself out by doing a bunch of cardio, just don't eat for 2-3 days a week. Not to mention increase stem cell production, growth hormone production, strengthens immune system, killing off old cells creating news cells, organ and digestive healing, detoxification, anti aging, awesome skin. It's the best thing any human can incorporate in their life.