Wow, thats alot of information you want!
I love New Zealand, I feel so lucky to have been born here.
I'm not sure about what I don't like about it, probably how (no offence) Americanised it seems to be getting.
I find it quite easy to live naturally here. Unless your living right in the centre of a city, nearly all houses have room for a vege garden. Its quite easy to find shops that specialize in organic food, also most supermarkets stock a small amount of organic food as well.
I'm not sure about the average diet, it used to be just a basic diet, but now that the fast food industry is spreading all over NZ people are eating out more. Fast food is a bit different here (but not alot!) the servings are smaller that the USA and I think there are more options. New zealanders are very high consumers of meat and dairy, are suppose because those a some of our biggest industries.
The economy is pretty strong at the moment, which of course means that all the experts are predicting a slump pretty soon, but i don't know how accurate those people tend to be.
The system of Government is MMP, this link will explain it better that I can
http://www.mmp.org.nz/mmpfpp.html. Hospital healthcare is free, but doctors are very expensive, although it is free for under 6 year olds to see a doctor. At the moment it is very easy to get natural health products, but the government is trying to bring in a policy of joint regulation with Australia which will mean that some natural health products will only be sold with a prescription. (Which basically means that you'll have to see a doctor to get a presciption, which they probably won't give because pharmacuetical companies have doctors in their pockets

- but I'll save that rant for another time!) So lets hope that it doesn't come through.
I'm not really sure what else to say. Anything alse you want to know? I'm happy to answer any other questions.