[Obesity and developing countries of the south].

An adult is considered as overweight if his body mass index is 25.0 kg/m2 or more and as obese if it is 30.0 kg/m2 or more. Since excess weight is a predisposing factor for many chronic diseases, e.g. diabetes, an increase in its incidence in the population is cause for concern. Until now, excess weight has been problem of epidemic proportions only in developed countries, but it has recently spread to the developing world. More than 30% of the population in Latin America, the Caribbean, the Middle East, and Northern Africa is overweight. Populations living on Pacific and Indian Ocean islands have the highest prevalence of obesity in the world. In Asia and Black Africa, the overall prevalence of overweight is still low but incidence is high in urban areas. In most of these countries, both underweight and overweight people can now be seen. In many countries, the increase in the number of overweight people has occurred within the last few years. Excess weight appears first among the affluent and then among low-income classes including young children and teenagers. The main causes are a nutrition transition to lipid-rich diets and, above all, reduced physical activity in city dwellers. Obesity and associated diseases could become major problems in the future since malnutrition during fetal development and early childhood are predisposing factors. Already overweight is creating an extra burden for countries where malnutrition and nutritional deficiencies are still observed in young children. Given the economic costs of management of obesity-related diseases, surveillance and prevention programs are needed to stem the growth of this problem.