China too must confront obesity

China is commonly thought to have one of the world's leanest populations, so it may be surprising to learn that an estimated one in six of its people - or 215 million individuals - are overweight, according to the WHO's definition.

The widening average girth seems to have grown hand-in-hand with the Chinese economy's steady expansion and globalisation's growing influence. In Beijing and Shanghai, McDonald's, Pizza Hut and Starbucks have become the eating places of choice for China's growing middle-class.

More sedentary lifestyles and changes to the traditional diet are among the many explanations proposed for China's newly acquired weight problem. National nutrition surveys indicate noticeable changes in the proportions and sources of dietary macronutrients over the past 20 years; energy intake from animal sources has risen from 8 per cent in 1982 to more than 25 per cent in 2002.

And the average energy intake from dietary fat among urban Chinese is approximately 35 per cent, comparable to levels observed in Western populations, and significantly higher than the upper limit of 30 per cent recommended by the WHO.

Root causes

China's obesity epidemic may have some roots in the prevailing social attitudes towards body fatness. In Chinese culture, there is still a widespread belief that excess body fat represents health and prosperity. This may be a consequence of the famines and chronic malnutrition that caused millions of deaths in the past two centuries.

It may partly explain the increased prevalence of overweight and obese people among older Chinese in both rural and urban areas. By contrast, the Western “cult of thinness” may be keeping urban women more resilient to the increasing trend for obesity.

Traditional dietary and eating patterns are also changing. The Chinese are eating more oil and consuming more fat. They eat more processed food at home and eat out more often.

All over China people are walking and cycling less, while the use of cars, buses and motorcycles is growing. Recent studies examining the role of physical activity in Chinese obesity have found that, among men, those who own a motorised vehicle are twice as likely to become obese.

According to the National Statistics Bureau, within only a decade the number of households owning a motorcycle rose from just under 2 per cent in 1990 to nearly 25 per cent in 2004, and, although less dramatic, the average number of cars per 100 households has increased by nearly 700 per cent - to just over two.

Further, the failure of urban planners to consider the promotion of physical activity when building inner city environments has made it increasingly difficult to find safe places to walk or exercise in residential areas.

Failure to address complexities

As in the West, China's obesity epidemic poses a considerable public health threat, but the means to tackle the problem remain elusive.

A recent overview of randomised trials trying to prevent obesity in children and adolescents in China found that none of the mainly single-pronged strategies were effective.