For what purpose are you trying to gain mass? Unless you are very thin - like with a BMI of 19 - Isn't that a bad thing? Doesn't it significantly shorten your

For what purpose are you trying to gain mass? Unless you are very thin - like with a BMI of 19 - Isn't that a bad thing? Doesn't it significantly shorten your life? Working out and staying thin is probably a good thing. Is there a reason to do it if not to be healthier? Here's a paper taking such a stance: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4115619/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4115619/