The PoU is an estimate of the proportion of the population whose habitual food consumption is insufficient to provide the minimum dietary energy levels that are required for an active and healthy life. It is related to the access dimension of food security. It is not a measure of food availability (although to compute the SDG indicator 2.1.1, one of the parameters is derived from information on national food supplies). 

The PoU is not a measure of undernutrition. Colloquially, the terms undernourishment and undernutrition are indeed very similar. In the more technical context of indicators of food security and nutrition, however, they are very different. Undernourishment, as measured using FAO’s PoU methodology, refers to inadequate access to dietary energy in a population. Undernutrition, on the other hand, refers to the nutritional status of individuals.  Specifically, undernutrition refers to conditions that result from deficiencies in consumption and/or absorption of dietary energy and nutrients, such as child stunting and wasting, and vitamin and mineral deficiencies.

The PoU is useful to:

• Estimate the proportion of a population that is persistently consuming an insufficient amount of food;
• Provide valuable information about general trends and changes in hunger over time; FAO has published global and regional estimates since 1974 and estimates for countries since 1999.
• Monitor progress towards Sustainable Development Goal 2 (SDG 2); the PoU was included in the 2030 Agenda for Sustainable Development indicator framework (SDG Indicator 2.1.1) to monitor progress towards zero hunger at global, regional, and country levels;  
• The PoU can support an analysis of the main causes leading to undernourishment, e.g. food availability and access to food;

The PoU is not useful to:

• Indetify undernourished individuals;
• Monitor short-term impacts of national or local level policies and programmes;
• Evaluate short term events that can affect food availability and access to food (e.g. price variations).

The PoU is estimated from the cumulative probability that the habitual dietary energy consumption (DEC), of the average individual in the population, is below the minimum value of the range of energy requirements (MDER) for the average individual. For the model, three parameters are required: the MDER, the mean DEC and the coefficient of variation (CV) of the DEC.

For global monitoring of SDG indicator 2.1.1, the mean DEC is estimated from the Dietary Energy Supply (DES) reported in the Food Balance Sheets (FBS), compiled by FAO based on the official data production and trade. The MDER for the average individual in the population is computed as the weighted average of the lower bounds of the energy requirement ranges for each sex and age group in the population, using as weight the proportion of individuals in each sex-age group. The population structure data is drawn from the UN-DESA World Population Prospects. Information on the median height in each sex and age group, which is needed for computing the MDER, is derived from nationally representative household surveys or from other sources. The CV is based on food consumption data from household consumption and expenditure surveys or from other nationally representative population surveys conducted in countries.

This is because the Food Balance Sheets (FBS) are based on a standardized methodology and are the source of the most up-to-date food supply data for almost all the countries of the world. The FBS are updated yearly, whereas food consumption data availability from household consumption and expenditure surveys is limited for countries/years around the world.

As there is a range of body weights and a range of lifestyles compatible with long-term good health; consequently, it means that even for an individual of given sex and age, there is a range of energy requirements compatible with long-term good health. This implies, that using the average dietary energy requirement as a threshold in the PoU model would yield a PoU of around 50% even if everyone in the population regularly eats according to their requirements. To avoid such bias, FAO uses the lower limit of the range of requirements as a threshold to establish inadequacy.

For more details see: Methodological issues in the estimation of the prevalence of undernourishment based on dietary energy consumption data: A review and clarification. L. Naiken, 2014. FAO Statistics Division Working Paper. 

The parametric approach used by FAO makes it possible to produce reliable estimates for relatively large population groups. The model is informed by three main parameters: 

• the mean dietary energy consumption (DEC), 
• the minimum dietary energy requirement (MDER), 
• the coefficient of variation of dietary energy consumption (CV). 
  

To apply a headcount approach, it would be necessary to have detailed data on the habitual dietary intake and dietary energy requirements of the individuals belonging to the different sex, age and physiological status groups in a population. But we rarely have this information. Therefore, such an approach is not feasible for producing regular estimates of hunger, especially for fulfilling FAO’s mandate of annual global monitoring. The PoU methodology is based on data that are more readily available for most countries in the world on a regular basis.

No. Unfortunately, no suitable analytic formula exists to calculate margins of error around the PoU estimates.

Beginning in 2021, FAO began publishing upper and lower bounds to the estimated PoU (and corresponding number of undernourished - NOU), however these do not reflect statistical margins of error. Rather, they reflect different assumptions made regarding the way in which unequal access to food may have contributed to rates of hunger in recent years. Making such assumptions was needed due to lack of direct evidence on food access during and immediately after the COVID-19 pandemic, when most statistical activities that required field operations were blocked. As we gradually move back to normal, it is expected that new direct evidence on the inequality in food access will become available, and that might reduce – though never eliminate – the residual uncertainty around our estimates. It is therefore expected that FAO will continue to present upper and lower bounds around PoU estimates, and that the range of possible values may become narrower than it was during the immediate post-pandemic years.

Subnational levels of the PoU can only be estimated using detailed food consumption data collected in household consumption and expenditure surveys, if the survey is designed to be representative to subnational levels.

Undernourishment applies to single individuals, however the indicator refers to the proportion of people in a population that is undernourished without identifying the individuals.

While the PoU can be estimated for some population groups, it would only be possible if detailed data were available on the habitual dietary energy intake and energy requirements of the individuals belonging to the different sex, age and physiological status groups in a population.  

No. It is nearly impossible to design a standard food consumption module that captures diverse food consumption patterns of all the countries. It is recommended to refer to: Food Data Collection in Household Consumption and Expenditure Surveys – Guidelines for Low- and Middle-Income Countries. 

There is indeed a bewildering amount of global food security reports that present different numbers based on different data sources and methodologies.  Here we will discuss only a few of the other main indicators commonly reported and their relationship with the PoU.

The PoU was included in the 2030 Agenda for Sustainable Development indicator framework (SDG Indicator 2.1.1) to monitor progress towards zero hunger. The other SDG 2 indicator is the Prevalence of Moderate or Severe Food Insecurity based on the Food Insecurity Experience scale (FIES) (SDG indicator 2.1.2). Annual updates of both of these indicators are presented in the annual State of Food Security and Nutrition in the World (SOFI), at global, regional and country levels, for rich and poor countries alike.

FAO disseminates estimates of food insecurity based on the FIES at two levels of severity: moderate-or-severe (combined), and severe only. People facing severe food insecurity have typically run out of food at times during the year and, at worst, gone an entire day or more without eating. As expected, the global trends in the prevalence of severe food insecurity based on the FIES are similar to the trends for the PoU. Both indicators provide evidence regarding the proportion of the population facing severe constraints on food access, albeit based on very different methodologies and sources of data.

Another widely-cited report is the Global Report on Food Crises (GRFC), which disseminates assessments of acute food insecurity based mainly on the Integrated Food Security Phase Classification/Cadre Harmonisé (IPC/CH), applied in a set of countries that are susceptible to food crisis situations. Both the GRFC and the SOFI are multi-partnership efforts that provide international assessments of food security; however, their objectives and geographical scope are distinct, and they rely on different data and methodologies. On the one hand, the SOFI has the broad objective of monitoring chronic food insecurity in the entire world, on a regular basis, by reporting on SDG Indicators 2.1.1 and 2.1.2. The GRFC, on the other hand, focuses more narrowly on acute food insecurity in countries experiencing food crises for the purpose of guiding immediate humanitarian response. Acute food insecurity refers to food insecurity in a specified area at a specific point in time and of a severity that threatens lives or livelihoods, or both, regardless of the causes, context or duration. The assessments based on IPC/CH are not statistical measurements, but rather the result of a process of convergence of evidence reached by a country team of analysts, based on the most recent available information from various sources. Within a country, rough estimates of the number of people facing crisis levels of acute food insecurity are presented that refer to the specific populations covered by the analysis, and not necessarily to the whole population at the national level.

Finally, another frequently-cited figure is the Global Hunger Index (GHI) score. The GHI score is calculated based on a formula that combines four indicators: the PoU, child stunting, child wasting, and child mortality. Thus, while the score includes the PoU in its calculation, it also includes other very disparate indicators of health and nutritional status. For this reason, the GHI is not comparable to the PoU. The global score is a population-weighted average of the score calculated for all countries, and is mostly used to rank countries and track trends.

In theory, a correlation would be expected with indicators of malnutrition, generally speaking. However, it is important to keep in mind that the PoU is a country-level, indirect estimate of access to dietary energy in the population, whereas malnutrition indicators refer to nutritional status of individuals (expressed as a proportion of the population). In general, countries with higher PoU would be expected to have higher levels of undernutrition, especially – e.g. child stunting and wasting and micronutrient deficiencies. However, since poor nutrition – in utero, as a child, and even as an adult – can increase risk of overweight and obesity later in life, the relationship between the PoU and indicators of malnutrition is complex.  

Yes, the FAO e-learning course https://elearning.fao.org/course/view.php?id=386 and metadata document of SDG-2.1.1 https://unstats.un.org/sdgs/metadata/files/Metadata-02-01-01.pdf.

Countries can request technical assistance through the FAO country office. In the case of requesting a national workshop, a needs assessment will be carried out once an official country request is received.

FAO facilitates regional and national trainings aimed at enhancing capacity in producing and reporting food security statistics from national level data. The trainings focus on enhancing skills of staff from ministries and other national, regional and international institutions working on food security assessment and monitoring to collect, analyze, interpret and use food security indicators, including the PoU (SDG indicator 2.1.1), producing evidence to guide policies to end hunger and malnutrition.

If you are interested in obtaining more information about capacity building workshops for officers in your team, please contact the FAO country office in your country, or write to: [email protected].