It's a matter of personal tastes and calculations. To me, the idea of spending enough time in the gym to make myself whatever the definition of healthy is (which seemingly no longer has anything to do with whether you're actually sick anymore) would result in a less enjoyable life than I experience as I am.
Just the thought of going to a gym makes me feel somewhat queasy. All that sweat and people in leotards. Gruesome.
And having to GO there and then come all the way home again and again and again for months and months and years. It's like the astronauts who have to exercise to stop their muscles and bones deteriorating. One russian cosmonaut said that for some it's okay because they like exercising but for those that don't it's a remorseless and depressing routine more akin to torture than anything else.
By any reasonable, non-aesthetic definition of healthyness I'm not unhealthy. The idea of going to a gym though does make me feel ill... so I'd rather not.
I think that more and more BBWs are learning that they don't have to be couch potatoes just because they are BBWs. I belong to a gym and I notice that more and more BBWs are there working out. It's all about health. Just because you're a big gal doesn't mean you can't be healthy!