The planet hates you and wants you dead. Everything is pretty much an adaptation to adverse circumstances that allow species to continue. That's about the best "guarantee" you'll get. If things go right, you'll live long enough to procreate. Anything after that is bonus time. People treat this stuff like religion. If they live The One True Way™ as "god" intended, they'll have a long, active healthy life, when a lot of it is "luck" and quirks of genetics. With infinite knowledge, the "luck" aspect would be removed, but we're currently stuck with luck.
That isn't to say a diet of beer, potato chips, and cigarettes is the way to go, but obsessing over small details isn't especially productive. You want a chocolate bar, eat a chocolate bar. Taking chocolate chemicals concentrated in pill form probably won't do anything but lighten your wallet and enrich grifters though.