When I was young, I thought older people who shrugged these kinds of things off with "when it's my time, it's my time" were irrational. I'm past the half-way mark now and I get it.
I am not going to spend my life on min/maxing my health, because no matter what I do, I'm going to die. If I exercise, first I'm spending my time on something I dislike, second I will likely end up with joint issues and instead of cancer I'll just be in chronic pain.
There are limits, and I'm sure I'm making these choices at least half-blind to the odds, but I'm making the choices regardless. I eat decently but not a health-optimized diet, I make sure I move around enough that I don't lock up, and I make sure I don't get too fat to be active when I choose to be active, but I enjoy life more with my brain than my body.
If that means I lose one of the 80-90 years I'm likely to allocated given my current health, I'm absolutely at peace with that outcome. Unless science can tell me that changing my habits will give me decades more life, it's just not worth it to me to change my lifestyle over a significant but ultimately small shortening of my potential lifespan.