A Curtin University-led study has found that where Australians live has a measurable influence on their body weight, with local food environments and neighbourhood design playing a big part in shaping health outcomes.
The research tracked the same Australians across 14 years and discovered that people who move to a new area gradually adopt part of the typical weight profile of their new community, showing that "place" itself contributes to differences in weight across the country.
Lead author PhD candidate Michael Windsor, from the Bankwest Curtin Economics Centre, said the findings show that tackling obesity requires more than just focusing on individual behaviours.
"By following thousands of Australians year after year and using broad two-digit postcode regions to identify when they moved, we were able to see how changing location influenced their weight," Mr Windsor said.
"On average, about 15 per cent of the difference in weight between regions can be explained by where people live, not just who they are. People tend to slowly gain or lose weight to align more closely with the average weight of their new area.
"That tells us that local factors such as the availability of healthy food, the density of fast-food outlets, walkability and access to green space, are quietly but powerfully influencing people's health."
Mr Windsor said the study also explored how location influences weight by examining changes in everyday behaviours.
"We found that the area in which people live has a much stronger effect on food consumption than on physical activity," Mr Windsor said.
"For example, up to half of the variation in how much people spend on groceries or takeaway food across different areas can be traced to the environment they live in. This suggests that what's available, affordable and convenient locally has a real impact on the choices people make."
The researchers used data from the long-running Household, Income and Labour Dynamics in Australia (HILDA) survey, which follows the same individuals every year. This allowed the team to identify when someone moved and analyse how their weight changed before and after the move.
Mr Windsor said the study offers new insights for policymakers looking to address Australia's rising obesity rates, with two-thirds of Australians now overweight or obese.
"Improving access to fresh food, investing in walkable neighbourhoods and designing healthier local environments could make a meaningful difference," Mr Windsor said.
"Individual choices matter, but the evidence shows that the places people live also have a significant influence. Effective policy must recognise both."
Published in Social Science & Medicine, the full paper, 'Product of our environment? Place effects on Body Mass Index', is available here.
