Weight watching in China
Obesity is not an image that is easily conjured up when thinking of the Chinese population, but according to the most recent statistics emanating from China an estimated one-sixth of the population, or 215 million individuals, are overweight (based on the World Health Organization’s definition of overweight as having a body mass index in excess of 25 kg/m2).
For a country that is traditionally viewed as having one of the leanest populations on the planet, the surge in the prevalence of overweight is largely symbolic of the country’s recent economic success and the power of globalisation. Nowhere is this seen more than in the large cities such as Beijing and Shanghai where McDonald’s, Pizza Hut and Starbucks have become the eating places of choice for China’s aspiring, and growing middle class. Professor Rachel Huxley Director, Nutrition and Lifestyle Division and Professor WU Yangfeng Director, The George Institute, China, give their perspectives on obesity and China.
Many explanations have been proposed to explain China’s recent epidemic of overweight and obesity including changes to the traditional diet, reduced levels of physical activity and increased sedentary lifestyles. Recent data from the National Surveys of Nutrition indicate that there have been noticeable changes in the proportions, and sources, of dietary macronutrients over the last 20 years; energy intake from animal sources has increased more than three-fold from 8% in 1982 to more than 25% in 2002. Moreover, the average energy intake from dietary fat among urban Chinese is approximately 35%, which is comparable to the level of dietary fat consumption observed in Western populations, and which is significantly greater than the upper limit of 30% recommended by the World Health Organization.
Part of the explanation for the obesity epidemic in China may also have its 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 is perhaps a consequence of China’s recent history where exposure to famine and chronic malnutrition were responsible for the deaths of millions of individuals in the past two hundred years. This attitude may partly explain the increased prevalence of overweight and obesity among older Chinese in both rural and urban areas of China. By contrast, the "Western cult of thinness" may account for the comparative resilience of young and adult urban women to the increasing trend for overweight and obesity among the Chinese populace.
Coinciding with China’s continuing modernisation are the reductions in physical activity and labour intensity not only in towns and cities but in rural areas. All over China, people are expending less energy on traditional forms of transportation, such as walking and cycling, whilst the popularity of motorised forms of transport such as cars, buses and motorcycles, is increasing. Recent studies that have examined the role of physical activity in obesity in China have found that unsurprisingly, ownership of a motorised vehicle doubles the risk of becoming obese among Chinese men compared with those that did not own a motorised vehicle. According to the National Statistics Bureau, within only a decade the number of households that owned a motorcycle rose from an average of just under two per 100 in 1990 to nearly 25 per hundred households in 2004, and although less dramatic, the average number of cars per 100 households has increased by nearly 700% to just over two. Furthermore, the lack of consideration towards constructing inner-city environments that promote physical activity has meant that it has become increasingly more difficult to find safe places in residential areas in which to walk or exercise.
As in the West, China's epidemic of overweight and obesity poses a considerable public health threat, but the means to tackle the problem remain elusive. In a recent overview of randomised trials for the prevention of overweight and obesity in children and adolescents in China, none of the mainly single-pronged strategies were shown to be effective, which may, in large part, reflect a failure to appreciate the complexity of the problem and the need for a multifactorial approach that encompasses sociological factors such as education, health information availability, access to media and cultural beliefs, and other important determinants for overweight and obesity. In randomised trials of adults, intensive behavioral interventions have been shown to result in modest but sustained weight loss but the feasibility of conducting such studies on a wide-spread basis in China is uncertain. Findings from the current study indicating a greater increase over the past decade in the prevalence of overweight and obesity in rural compared with urban areas, and among males compared with females, suggest that if China is to achieve what the West has so far failed to do in halting the obesity epidemic, innovative obesity prevention and intervention programs, that are culturally-relevant, are required.
About Professor WU Yangfeng - Director, The George Institute, China
Professor WU Yangfeng
About Associate Professor Rachel Huxley - Director, Nutrition and Lifestyle Division
Associate Professor Rachel Huxley