Читать книгу Clinical Obesity in Adults and Children - Группа авторов - Страница 69

The increase in the prevalence of obesity in the last 30 years demonstrates the importance of changing environmental factors, in particular the increased availability of cheap, palatable, energy‐dense foods and the reduction in physical activity during work and leisure time. Further evidence for the critical role of environmental factors in the development of obesity comes from migrant studies and the “westernization” of diet and lifestyles in developing countries. A marked change in body mass index (BMI) is frequently witnessed in migrant studies, where people with a common genetic heritage live under new environmental circumstances. Pima Indians, for example, living in the United States are on average 25 kg heavier than Pima Indians living in Mexico [2]. A similar trend is seen for Africans living in the United States and Asians living in the United Kingdom. Moreover, within some ethnic groups the prevalence of obesity has increased very dramatically not only amongst migrants but also amongst the indigenous population. In fact, the prevalence of obesity is currently more than 60% in Nauruan men and women in Micronesia and amongst Polynesians in Western Samoa, suggesting that people from these ethnic groups are more susceptible to developing obesity and that environmental factors have varying effects depending upon genetic background.