English summary: HBSC STUDY: OVERWEIGHT, SELF-PERCEIVED BODY WEIGHT AND DIETING IN 15-YEAR-OLD ADOLESCENTS IN EUROPE, ISRAEL AND NORTH AMERICA

Obesity is a major public health concern, described by WHO as "a global epidemic" due to its high and increasing prevalence. There appears to be a dichotomy of concern about the issue of body image, weight control and body weight in young people. The aim of this study is to describe the prevalence of overweight and obesity and self-perception of body weight and dieting among overweight 15-year-old adolescents in Europe, Israel and North America.

Data for this study were obtained from a large WHO collaborative cross-national survey on Health and Health Behaviour in School-aged Children (HBSC). The data were collected in 2001/2002 through school-based surveys, using the international research protocol.

The prevalence of overweight differed greatly between countries. Overweight was most common in the USA, where one third of boys and one fifth of girls are overweight. The gender difference remained stable across almost all HBSC countries and regions. A majority of overweight girls reported dissatisfaction with their body but many overweight boys were satisfied with their weight. In addition, overweight girls were more likely than boys to report engaging in weight control behaviour.

The avoidance of excessive weight gain in young people would prevent the development of obesity and have implications for their future health. It is therefore vital for the prevention and treatment of overweight and obesity in young people to develop multifaceted, effective and evidence-based programmes that support lifestyle changes: the results indicate that most overweight young people, especially girls, are motivated to reduce their weight.