ValorMaxim:
That's not necessarily true. You can eat healthy, have a balanced diet, and still have health issues. You can eat junk and sit on your ass and live well into old age.
A balanced diet, physical exercise, plenty of sleep, being outside, increasing lean body mass, being mentally active, and reducing excess weight all optimize your biological processes.
Being heavily and larger does have a cost. Even if you're healthy in every other way, over time excess weight beyond your biological predisposed norm causes stress that builds up and causes issues. From wear on joints, to stress on organs, to increased accident potential, to hormone fluctuations outside of your bodily norms. It all impacts your health.
You shouldn't let it dissuade you from being and doing what you want though. Just be aware of the consequences, and know them. Mitigate what you can, and deal with the rest as it comes.
Yeah, you could have genetic dispositions to different health issues, but you have to get really big for the kind of joint damage you're talking about.
I'd simply say everything is a risk to some degree so, that's why gaining weight is a personal choice.