It may feel counterintuitive, but you're losing muscle up to 3 days, after that it stops, as the organism ramps up HGH production 10x. Also stem cells are released, which repairs the organism where it is necessary.

I do it 6 years already and experienced all effects myself. 

 🤯

I need to look into this 

 I’m late day two. No muscle or strength loss yet. (At the gym now) Didn’t notice it during other 3 day fasts either 

 is there a research done on it or is that just a conclusion done on your personal experience? 

 Yes. There are several researches done.