Computing the Prevalence of Undernourishment (PoU)
The PoU is an estimate of the proportion of the population whose usual daily per capita dietary energy consumption is insufficient to provide the dietary energy levels that are required to maintain a normal active and healthy life. Specifically, for each country, the distribution of usual daily per capita dietary energy consumption in the population is compared with a range of dietary energy needs (derived from the composition of the population by age, sex and physical activity levels) to produce an estimate of the proportion of the population that lacks enough dietary energy for a healthy, active life.
The approach adopted by FAO allows obtaining reliable estimates for relatively large population groups. The model is informed by three main parameters:
- the average dietary energy consumption (DEC),
- the minimum dietary energy requirement (MDER),
- the coefficient of variation of dietary energy consumption (CV).
Dietary energy consumption
The DEC is the mean of the distribution of dietary energy consumption for the average individual in the population. It can be estimated from household consumption and expenditure surveys (HCES) or individual quantitative intake dietary surveys, in which cases PoU estimates can be derived also at subnational level. Nevertheless, representative surveys, of the whole population, that collect food consumption data are still not available for every country and every year. For the national population only, DEC can be estimated also from food balance sheets maintained by FAO for most countries in the world.
Minimum dietary energy requirement
The MDER is an average of the minimum energy requirements of all demographic groups in the population and it represents the minimum energy required by an average individual for a healthy and active lifestyle. It is computed based on the FAO/WHO/UNU Expert Consultation in 2001, which established energy standards, published in 2004, for different sex and age groups based on normative body weights for attained heights, international standards of BMI, normative physical activity levels, birth ratio and under five mortality rate.
Coefficient of variation of dietary energy consumption
The CV is an indicator of the dispersion in the food consumption distribution within the whole population, thus of the inequality in access to food. It can be estimated from household consumption and expenditure surveys or individual dietary intake surveys. When appropriate data for directly estimating this parameter are not readily available, FAO implements indirect procedures to estimate a suitable value with the objective of monitoring progress towards SDG Indicator 2.1.1.