Not sarcasm. I've been a gym rat for the past 30 years, working out with dozens of people in serious fashion over that time spam. If you want to attribute the f

Not sarcasm. I've been a gym rat for the past 30 years, working out with dozens of people in serious fashion over that time spam. If you want to attribute the following to bro-science or small non-scientific study samples (this would be about a N=45) go right ahead, it's not going bother me. I started using IF around 15 years ago after a workout partner recommended it to me. I had great success with it and have been a big proponent of it since. I have never seen anyone lose muscle mass which would be counter to their efforts in the gym (worked mainly with strength athletes and bodybuilders). Bodybuilders will frequently use IF when on a cut but not prepping for a competition (that's usually a different protocol). Strength athletes will use IF to lose excess fat making them faster and more explosive. I've seen it work too many times. Some of these guys competed in their varying sports so any sign of counterproductive output would have resulted in them immediately abandoning it. I think the confounding factors are quality of the diet, level of exercise, sleep patterns, and overall health state. None of these as far as I can tell are accounted for in the study. Going further there are countering studies (for example https://pubmed.ncbi.nlm.nih.gov/20300080/ https://pubmed.ncbi.nlm.nih.gov/20300080/) that show that fasting (TR, ADF, etc.) are muscle sparing. This only makes sense from an evolutionary standpoint since the human race would no longer exist at the first major famine, which we've managed to survive a few times over. So, I think there's more to the story here than what the good doctor presented.