You are right, it's a complicated matter, lots of variables.

I try to avoid things that I believe might damage my health, but I don't always manage it, lol. I'm trying to buy mostly organic food, but the truth is I'm a lazy cook, so at least a couple of times a week I go back to pizza, pre-cooked meals etc. I also can't resist coke or coffee, spend too much time on the computer, and live in a city so there's lots of car fumes.