I can criticise Australian urban planning for days ... but many visitors to Australia do effuse about how much outdoor recreational space we have and plan for.
First link has Australia, the country, at 32% obesity Vs. USofA at %41.6.
My only observations, having travelled in both, is that Australia like eveywhere has gotten more urban in past 20 years and I've got a feeling the percentage of Australians significantly past the technical bar of "obese" is very low compared to rates in the US of "well past" "just merely obese".
I'm not sure anyone's broken down the obesity quintile demographics.
Eg: Perth's 7km park: https://www.facebook.com/reel/1362227242068763 and https://www.tiktok.com/@9newsperth/video/7553237387548134712
AU Aintree North Recreation Reserve : https://www.youtube.com/watch?v=k5vYNG2eL9g
Skate parks, woops, river and coastal setbacks: https://www.youtube.com/watch?v=HfLa32K74Zw