Some people are naturally thin and some people are naturally heavier. It doesn't mean that bigger is healthier, or much thinner is healthier, it's on an individual basis.
I didn't get into music to become a blues musician, or a country musician. I'm a singer-songwriter. In my book that means I get to do whatever I want.
It's difficult to gauge that. With a bad guy you just know you're bad. To play a nice guy is harder - unless you are a very nice person like me of course.