Peter Attia· MD
so fat-free mass of course is a very good proxy for lean mass or muscle mass and you can see that these have data collected all the way from when people are teenagers up until the end of life and again you don't really have to be a statistician to see the remarkable Trends here so there's some obvious differences between men and women the most notable one of just the difference in lean mass men have significantly more lean mass than women but if you put that aside you'll realize two things the first is that we have a steady increase in muscle mass and lean mass both for men and women that occurs from birth right up until about the age of 25 and then you have a relatively minor decline in lean mass from 25 to 75 but then what happens at 75 Nick yeah it's off a cliff it literally falls off a cliff