You're right about the main thrust of the article, however a significant part of the article did argue about health issues, obesity and taxing unhealthy living,

You're right about the main thrust of the article, however a significant part of the article did argue about health issues, obesity and taxing unhealthy living, which I think weakened his argument somewhat. So as a counter to that side of the piece, I think it's ok to mention the difference between muscle/fat etc.