Addiction is a bit of a strong word. Maybe "crave"?
Cheese like heroin? Cara, maybe you should try kicking the habit by stepping down to Cheez Wiz in the spray can? That stuff will get you to quit.
They say the same thing about kids and sugar, especially soft drinks. It's all a media trick to catch your attention so that you read it.
marc7 is totally right, salt and sugar is addictive. They're in EVERYTHING.
Most people either prefer salty or sweet things. Personally, i have a weakness for Salty. Don't know if that's a "nature or nurture" thing. IOW were you born with a preferences based on heredity (nature) or something you acquire based on what you eat growing up (nurture). I'm guessing a little of both. It's kind of inseparable with food preference.
By spicy, do you mean HOT (as in peppers)? I like HOT stuff too, but too hot and you sweat like crazy. Here's something that I heard about eating HOT foods that I though was interesting and didn't think about it until i heard it, but it is totally true. Do you know why most people like HOT foods? It's not because of the taste because really hot stuff you can't taste anyway. The reason you like HOT foods is... you like how your mouth feels as it's cooling down. What do you think?
Most things in moderation are OK. The way I look at it is, you could be the healthiest person in the world so what happens if lightning strikes you and kills you or you are run over by a bus. What good was being perfectly healthy all that time going to do for you then?