Body mass index and body energy stores in developing countries.

Body mass index (BMI) is used widely as an index of fatness (the proportion of the body as fat) but its application to the low weight and stature populations in developing countries has not been established. As BMI is an indicator of size (the amounts of fat and fat free masses) as well as fatness, its relation to fatness and interpretation as a measure of energy stores may vary in different groups. Very low BMI reflects low fat and fat free mass, a state for greater concern than low fat mass alone, and possibly more typical of chronic energy deficiency.