I no longer live in Australia, but i did for 22 years. You will have no
problems at all finding fresh fruits and vegetables in Australia. Both are
in abundance and of high quality! Lots of products in Australia have labels
with all thier nutritional details, so you can check out what you are
buying. There are lots of health food stores in the main cities. I don't
know about finding fat free breads but I would think it won't be a problem.
RE: vege restaurants. I keep kosher so didn't eat out much in Sydney, but a
great place to try is The Fernery on the North Shore of Sydney, assuming it
still exists. I dont know how fat free it is but it is tasty and vegetarian.
There is a Hare Krishma place in the inner city of Sydney that is vegan/vege
and also meant to be great. There are loads of restaurants in Sydney.
I hope this heps. In general I don't think you will have any problem finding
healthy food in Australia.
Good luck and enjoy your trip.