Nutrition in transition: the changing global nutrition challenge.

The rapid shift in the stage of nutrition towards a pattern of degenerative disease is accelerating in the developing world. Data from China, as shown by the China Health and Nutrition Survey, between 1989 and 1993, are illustrative of these shifts. For example, an increase from 22.8 to 66.6% in the proportion of adults consuming a higher-fat diet, rapid shifts in the structure of diet as income changes, and important price relationships are examples that are presented. There appears to reflect a basic shift in eating preferences, induced mainly by shifts in income, prices and food availability, but also by the modern food industry and the mass media. Furthermore, the remarkable shift in the occupations structure in lower-income countries from agricultural labour towards employment in manufacturing and services implies a reduction in energy expenditure. One consequence of the nutrition transition has been a decline in undernutrition accompanied by a rapid increase in obesity. There are marked differences between urban and rural eating patterns, particularly regarding the consumption of food prepared away from home. Other issues considered are the fetal origins hypothesis, whereby the metabolic efficiencies that served well in conditions of fetal undernutrition become maladaptive with overnutrition, leading to the development of abnormal lipid profiles, altered glucose and insulin metabolism and obesity. Furthermore, obesity and activity are closely linked with adult-onset diabetes. The shift towards a diet higher in fat and meat and lower in carbohydrates and fibre, together with the shift towards less onerous physical activity, carries unwanted nutritional and health effects. It is also clear that the causes of obesity must be viewed as environmental rather than personal or genetic.