ABSTRACT
The epidemiology of obesity was for many years difcult to study because many countries had their own specic criteria for the classication of different degrees of overweight. Gradually, during the 1990s, however, BMI (weight/height2) became a universally accepted measure of the degree of overweight, and now identical cutoff points are recommended. This most recent classication of overweight in adults by the World Health Organization (WHO) [3] is given in Table 4.1. In many community studies in afuent societies, this scheme has been simplied and cutoff points of 25 and 30 kg/m2 are used for descriptive purposes. The prevalence of both very low BMI (<18.5 kg/m2) and very high BMI (40 kg/m2 or higher) is usually low, on the order of 1% to 2% or less.
