The number of fast food outlets in any given country may be linked to increasing obesity rates there, a new study suggests.

According to an international team of health researchers, a number of studies have already found a link between the types of meals served at fast food outlets and obesity. However, they decided to investigate whether there is a link between the number of such outlets in a country and obesity.

They looked at the number of Subway restaurants per 100,000 people in 26 ‘economically advanced countries', including Ireland, the UK, France, Germany, Australia, the US and Japan.

The researchers took into account other factors, such as rates of obesity in people over the age of 15, gross national income and levels of motor vehicle use.
However, they found a positive link between the number of fast food restaurants in any given country and the rate of obesity among its population.

In other words, countries with a higher number of fast food outlets tended to have higher levels of obesity.

For example, Australia had the highest number of Subway restaurants at around 21 outlets per 100,000 people and its adult obesity rate was 20% among men and 25% among women.

Japan on the other hand had 0.13 outlets per 100,000 people and its obesity rate was just under 3% among men and just over 3% among women. These were the lowest rates of obesity found among the 26 countries.

The highest obesity rates overall were found in the US - 31% in men and 33% in women - and it had the second highest number of outlets per 100,000, at 7.52.

Ireland was found to have 2.62 outlets per 100,000 people and an adult obesity rate of 14% in men and 12% in women.

The researchers emphasised that their study does not prove that the density of fast food outlets causes obesity, however there does appear to be a link.

"Although our results are preliminary and exploratory, they suggest that the diffusion of fast food outlets, and trade liberalisation policies promoting their growth and expansion worldwide, may contribute to the obesity epidemic," they concluded.

Details of these findings are published in the journal, Critical Public Health.