Introduction: the challenge of adult chronic energy deficiency

In Guatemala, in 1987, the term 'chronic energy deficiency' (CED) was being used as a term to indicate an inadequate household food supply. Since then, attempts to define, measure and assess CED have evolved, using the body mass index (BMI or weight/height) of individuals as the index of CED. An estimate of food intake or physical activity was incorporated into the early analyses, but has since been discarded as difficult and unnecessary because so many people of normal BMI were found to be inactive. Provisional cut-off points for low BMI were developed to define grades of CED in the same way as Garrow used higher levels of BMI to define different grades of obesity. The same BMI cut-off points were proposed for men and women in the absence of suitable data for proposing sex-specific cut-off points. Since then, we have been collecting and sifting worldwide data to test the validity of BMI as a measure of CED. FAO has helped in making data available with extensive information being obtained from China, India, Ethiopia and Zimbabwe. There is now clear evidence that those with a low BMI have more sickness, a lower work capacity, limited social activity, and a lower income. Mothers with a low BMI also have a greater proportion of low birth weight babies compared with those of normal BMI. Three challenges remain before confirming the use of BMI as the key to specifying a state of CED: Is it valid? Does it apply to individuals as well as populations? What are the causes of CED?(ABSTRACT TRUNCATED AT 250 WORDS)