Peter Attia stopped fasting due to difficulty regaining lean muscle mass, losing approximately 20 lbs of muscle over three years.

“I had lost I don't remember the exact number but it was it was getting close to 20 lbs of muscle you know it might have been 16 pounds of muscle over that period of time because at at least at the frequency that I was fasting which I'm not saying was right or wrong um it's very difficult to gain back the lean muscle you keep losing”

“the second one was actually was just more of a social issue which was at the time that I was fasting I I also happened to be traveling a lot right so I was um it was very easy for me to fast when I was away from home so all of those fasts were done while I was in New York and you know I lived in San Diego so I didn't have to be fasting around anybody I was just fasting in my apartment alone and even if I went out to dinner with friends which was weird but I did you know I would just sit there and drink you know soda water while they were eating dinner Joo famously tells a story about that one night um but once I stopped traveling um it meant Oh all those fasts are going to have to be done at home and honestly like I just didn't I just didn't want to do it you know I didn't I didn't I don't want I don't want my kids to be wondering like why is Daddy never eating and all that kind of stuff”

“I just took a kind of look at the data the bigger data of myself and realized over the course of three years I had lost I don't remember the exact number but it was it was getting close to 20 lbs of muscle you know it might have been 16 lbs of muscle over that period of time because at at least at the frequency that I was fasting which I'm not saying was right or wrong um it's very difficult to gain back the lean muscle you keep losing right you you lose a ton you regain some of it you lose a ton you regain some of it but I just couldn't dig out of that hole”