Obesity linked to money insecurity in affluent nations
People in wealthy countries with "free market" economies are more likely to become obese, an Oxford University study says.
Money stresses in countries like the UK and US could explain their higher obesity levels, compared with countries such as Norway and Sweden.
The study, in Economic and Human Biology, compared obesity in 11 affluent countries from 1994 to 2004.
The researchers said the study showed obesity had "social causes".
Researchers set out to discover why Americans and Britons are heavier than Norwegians and Swedes.
Taking into account research into animal behaviour which shows that animals increase their food intake when faced with uncertainty, the Oxford researchers believed that stress could be a factor in causing people to overeat.
So they analysed data on obesity levels using 96 national surveys carried out over 10 years across a number of different countries.
They looked at 'market-liberal' countries including the US, UK, Canada and Australia.
These were compared with Finland, France, Germany, Italy, Norway, Spain and Sweden - which traditionally offer stronger social protection and higher levels of economic security.
The study found that the more market-liberal countries stand out as having high levels of obesity - one-third more obesity on average - and higher rates of obesity growth.
This is true even when compared with other affluent countries with similar levels of incomes, the study says.
The USA had the highest levels of obesity (with a mean of around 30% obese), whereas Italy, with the lowest prevalence, had almost half the levels (around 17%).
Professor Avner Offer, lead study author and professor of economic history at the University of Oxford, said: "Policies to reduce levels of obesity tend to focus on encouraging people to look after themselves but this study suggests that obesity has larger social causes.
"The onset and increase of large-scale obesity began during the 1980s, and coincided with the rise of market-liberalism in the English-speaking countries.
"It may be that the economic benefits of flexible and open markets come at a price to personal and public health which is rarely taken into account.
Professor Offer explained that market-liberal reforms have created more competition in some societies, and this has also undermined personal stability and security.
"It suggests that the economic benefits of flexible and open markets, such as they are, may be offset by costs to personal and public health which are rarely taken into account."