ABSTRACT
In the mid 1990s, WHO undertook an evaluation of underweight and overweight in both children and adults (World Health Organization, 1995). At that stage the problem of chronic energy deficiency in adults was being recognized for the first time (James et al., 1988), but when representative data were obtained from a number of countries it soon became evident that underweight or ‘chronic energy deficiency’ of adults was comparatively unusual and that many developing countries had a far greater problem of excess weight (Figure 1.1). For this analysis the standard measure of body mass index (BMI, kg/m2) was used and, in order to accommodate the problem of underweight in adults, it was recognized that the lower limit of the normal range of BMI should be extended to 18.5 (Table 1.1).
