Jim Fixx didn’t eat well. He was also a long time cigerette smoker. Avid ciggie smokers average live span is into their early 60’s.
One of my uncles smoked and jogged, dropped dead on one of his morning jogs.
Another uncle smoked a pipe for 50+ years and died a lingering cancerous death at 74.
My wife's “little sister” was up visiting a couple months ago. Because she is so fat and out of shape, we had to push her everywhere in a wheelchair. Any trip more than half an hour in the car required a cigarette stop. When she wasn't smoking, she was vaping her “medicinal” marijuana She is in her early 60s. I do not expect her to get to 70. A life time of bad choices is to blame.
And he had a congenital heart problems and didn’t eat right (at his autopsy three of his coronary arteries were blocked - 95%, 85%, 70%).
I read that the men on one side (his fathers side I think) never made it past their late forties. Partly genetic I guess.