Counterpoint: strongman competitors are often incredibly unhealthy. They are also literally the strongest humans on earth, who dedicate their lives to the singular pursuit of being able to pick up more weight than anyone else on the planet. Eddie Hall, this year's WSM, retired from the sport after achieving the win, because he has been destroying his health in pursuit of the title. Strongmen are famously at elevated cardiovascular risk, and they nearly universally require CPAP machines to sleep because their weight puts them at serious risk of death by obstructive sleep apnea. NFL defensive linemen tend to be in a similar position - very strong, very athletic, and at very elevated risk of fatal or debilitating health conditions.

One can be extremely strong and extremely competent - world class, even - and still not be fit.

Of course there are always outliers. However, the older you get the less likely you are to be overweight. That is, you'll typically die sooner, not later. I'd say ("premature") death qualifies as unhealthy ;)