China must confront changing diets, more sedentary lives, and a 'plump is prosperous' culture to halt obesity, say Rachel Huxley and Yangfeng Wu.
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 twenty years; energy intake from animal sources has risen from eight 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.
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 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 two 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.
Interventions often fail to address the complexity of the problem. For instance, programmes targeting childhood obesity only focus on the child but not the family, school and community — all of which can affect the outcomes. Interventions also need to encompass sociological factors such as education, availability of health information and media, and cultural beliefs.
Future strategies could focus on changing food pricing policy, influencing school policy on health matters and physical education, and changing the content of school canteens. Policies should aim to modify the environment, at both the school and community level, to support healthy lifestyle behaviours in children and adolescents. Educating parents and other care-givers to reinforce key messages outside school is also vital for any obesity intervention targeting children.
National plan being developed
Since 2005, a programme called Happy 10 has been operating in schools in Beijing and other cities. It includes 45 types of activities from rope skipping to the triathlon. The education ministry has recommended that group dancing be incorporated into the national curriculum. And in May 2007, the Chinese Preventive Medical Association launched China's first week-long campaign against obesity in Beijing, Guangzhou, Shanghai and Shenzen. It includes lectures by experts and free examinations to make people more aware of the hazards of being overweight.
The Ministry of Health is developing a national plan to prevent and control chronic diseases, which recognises obesity as a key risk factor for ill-health. A national education programme on healthy lifestyle was initiated in May 2007, which included information on what constitutes a healthy diet and suitable levels of physical activity. But it will be several years before it can be evaluated.
Randomised trials show intensive behavioural interventions bring modest but sustained weight loss for adults.
Yet the China Nutrition and Health Examination Survey from 2002 — a nationally representative survey repeated every ten years on 250,000 randomly sampled individuals in China — suggests excess weight and obesity is increasing more in rural compared with urban areas, and more among males than females.
If China is to achieve what the West has so far failed to do, and halt its obesity epidemic, innovative and culturally-relevant prevention and intervention programmes are urgently required.
Rachel Huxley is director of the nutrition and lifestyle division at the George Institute for International Health, Sydney University, and Yangfeng Wu is director of the George Institute, China, and director of the clinical research programmes at Peking University Health Science Centre.