I don't think that anyone, at any point, has said that anyone should not try and be healthy and avoid the things you've listed, nor do I think I've read anyone condoning 'sit(ting) doing nothing all day', though I'll stand correctly if I've missed that advice in a post. I think the issue could be the inferrence that anyone bigger than Jill Franks is overweight, and that anyone who is bigger than that is that way because they don't try. As I think most of us are aware, not everyone is made the same, and there are many and varied reasons why people are different shapes and sizes. Being so does not necessarily make us fat, lazy, unhealthy or wrong.
