Empirical findings on women’s and children’s nutrition should be evaluated using a holistic approach. In fact, individual malnutrition can be the consequence of household food insecurity, sickness, or poor sanitation/caring practices; or it can derive from the combined effect of those factors. In addition, the analysis should take into account as much as possible intra-household dynamics: for instance, lack of food at the household level does not necessarily result into children’s malnutrition, especially if children are protected against infections and mothers diminish their food intake to preserve children’s consumption.
Sex differentials in nutrition may be clearer when data on weight and height of girls and boys under 5 are disaggregated by age. Under age 2, the biological vulnerability of boys to infections may reduce their nutritional status. Above age 2, the biological factors are less relevant.
Women’s BMI is generally measured either on adult non pregnant women (18 years old or more) or reproductive-aged women (15-49). Any comparison should carefully reflect on the reference population and compare the same age groups. Along the same line, nutritional status of young girls (i.e., below 18 years of age) should be measured using the BMI-for-age.
Weight is not to be taken in case of oedema and pregnancy because they introduce a bias in the weight value. For this reason, and for the high measurement costs, some surveys measure nutrition through the Mid Upper Arm Circumference (MUAC).
Age patterns in height of adult women over age 20 (the height of an adult women is considered stable after age 20) can be used to assess improvements or deteriorations in nutritional status along cohorts of women. Increases in height over generations are historically linked to health transition, in particular with the control of infectious diseases, as well as with improving nutrition. Normally, the average height of adult women is increasing from one generation to another. However, in some countries, negative trends in the height of adult women over age 20 from older cohorts to the younger cohorts have been observed (Garenne, 2011). These negative trends along cohorts are indicative of deterioration in the overall nutritional status of women. Similar analysis can be done for cohorts of men, although anthropometric data on men are less often available.
Data on storage, food preparation and processing are rarely available and international standards have not been set so far.