Israel is a multiethnic society and offers an ongoing 'experiment' concerning the cultural determinants of obesity. The First Israeli National Health and Nutrition Survey 1999-2001 (MABAT) measured a representative population of 2782 adults (49% men) aged 25-64 years (mean 43 years); it showed a prevalence of overweight in 39.3% and obesity in 22.9%. Overweight is more common in men and obesity is more prevalent in women; the Israeli Arab population is more obese than the Jewish one.