World obesity doubles since 1980 as Western lifestyle embraced

Scientists investigating risk factors for heart disease found evidence of an obesity pandemic as more countries embrace "Western" lifestyles and diets.

In 2008, more than half a billion adults worldwide – 205 million men and 297 million women – were clinically obese. This means they had a body mass index (BMI), measured by dividing a person's weight in kilogrammes by their height in metres squared, of 30 or above.

An estimated 9.8 per cent of men and 13.8 per cent of women on Earth were obese in 2008, compared with 4.8 per cent of men and 7.9 per cent of women in 1980.

Pacific island nations had the world's highest obesity rate, with average BMI levels reaching 34-35 – up to 70 per cent higher than some countries in south-east Asia and sub-Saharan Africa.

Among high income countries, the USA had the highest average BMI level of 28 for both men and women. Being overweight is now the norm for the average American.

The picture was similar in Britain, which had the sixth highest BMI in Europe for women and the ninth highest for men. Both men and women in the UK had an average BMI of around 27. The "overweight" BMI range is from 25 to 30.

Three papers published yesterday in The Lancet medical journal analysed global levels of obesity, cholesterol and blood pressure by drawing together the available data. In contrast to obesity, the proportion of the world's population with high blood pressure fell between 1980 and 2008. This was despite the total number increasing from 600 million to almost a billion.

High income countries achieved the biggest blood pressure reductions, and also saw falls in average levels of total blood cholesterol. But this good news masked shifting patterns with some countries facing problems not encountered before.

Systolic or "heartbeat" blood pressure levels were highest in Baltic and East and West African countries, matching those in some parts of western Europe in the 1980s.

Cholesterol levels had shown increases in Japan, China and Singapore where they were historically low. Experts believe this is partly due to a dietary switch to more animal products and fats.

Britain's average blood cholesterol level in 2008 was the ninth highest in the world at just below 5.5 millimols per litre (mmol/l).

However, the UK also saw one of the fastest drops in cholesterol level of all high-income countries.