I'm perfectly fine the way I am, thank you. I'm not even overweight.
The truth is, getting up and moving is good even if you're thin.
It turns out being sedentary is a health risk. Period. It's up there with high cholesterol, high blood pressure, even smoking, according to a 2010 article in the Journal of the American Heart Association. In fact, fitness level is a "more powerful predictor" of survival than traditional risk factors, the journal says. That means an active person who's overweight can have a better prognosis than a thin, sedentary person.