Chapter 2


 Body Mass Index (BMI) is becoming more accepted as the best anthropometric way of
 identifying changes in the wellbeing of adults. This index is calculated by dividing weight
 (W), measured in kilos, by height (H), squared, measured in metres:

 W
 BMI =-

 Depending on the degree of undernutrition or obesity of the subject, the BMI can take values
 between 15 and 40. The following classification has been proposed:

 below 16 severe chronic malnutrition
 16-17.5 chronic malnutrition with wasting
 17.5-18.5 chronic malnutrition, underweight
 18.5-25 normal
 25-30 overweight
 over 30 obese

 If information on adult BMIs were to be taken as a matter of course, then it would be
 possible to develop a composite index of household health which included all members of
 the household, rather than categorising households according to child health alone.

 The choice of anthropometric indicator depends on a number of factors, including cost and
 ease of collection, but also the purpose for which they will be used. Anthropometric
 indicators are often used for screening children in emergencies, to establish eligibility for
 relief programmes. The indicator of choice here, arm circumference or weight for height,
 will be different to that appropriate for assessment of long-term food security problems at a
 national level.

 3.2 Interpretation of nutritional indicators in food policy analysis

 There are three major problems in the use of anthropometric indicators for food policy
 analysts: to determine whether the problem indicated is actually a food security problem, as
 opposed to, for example, a public health problem; to determine how significant the problem
 indicated by nutritional information is; and to determine what an appropriate policy response
 might be.

As has been mentioned before, a nutrition survey can indicate severe nutrition problems
 which do not arise from inadequate availability or access to food. Rather the problem may be
 one of chronic gastro-intestinal disease, resulting from inadequate sanitation, or a problem of
 a disease such as malaria interacting with mild malnutrition to result in severe nutritional
 problems. One way of pinning down the problem further is to examine a combination of
 nutritional and food consumption data, particularly food expenditure rather than intake, to
 identify whether a problem of access to food exists. Health indicators may also clarify the
 likely causes of poor nutritional status. No one data source will give a clear picture of the
 sources of the problem. A picture has to be built up using whatever information exists.


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