I've found over time that neither aphorism is true. The poison is poison, regardless. Caffeine, Sugar, Plastic, Alcohol, Social media --- all bad like arsenic, but tastier (or more useful).

I want to drink some sugar free beverage that's not just water, and find that my only option is typically caffeinated (or alcoholic, which is nearly the same as sugar).

So indeed, decreasing poison intake is a good thing. Since life is inevitability fatal, I'll probably not go to the extreme of eliminating any of those.