Hunger and Undernourishment

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Max Roser and Hannah Ritchie (2018) - "Hunger and Undernourishment". Published online at Retrieved from: '' [Online Resource]

I. Empirical View

I.1 Undernourishment over time, by world region

The prevalence of undernourishment, as a share of the population, is the main hunger indicator used by the UN's Food and Agriculture Organization.

It measures the share of the population which has a caloric (dietary energy) intake which is insufficient to meet the minimum energy requirements defined as necessary for a given population.

The visualisation below shows the prevalence of undernourishment by world region. The chart focuses on the regions and countries with the highest share of undernourished people. Developed countries, as defined by the FAO, are not included in these regional estimates of the FAO since they estimate the share of undernourished people in developed countries to be below 5%. This means, for example, that Japan is not included in the estimate for 'Eastern Asia'. Those world regions in which the prevalence is below 5% over this period are also not included.

I.2 World map of the prevalence of undernourishment

The global map of the prevalence of undernourishment- as a percentage of the total population- is shown below, from 1991 onwards.  As noted above, regions with a prevalence <5% are not included in these figures. You can view individual trends for any country over time by selecting it on the map.

In 2015 we see that only one country- Haiti- has greater than 50 percent of the population defined as undernourished. In 1991, there were nine countries with more than half of the population undernourished.

Today, the majority of countries have prevalence levels below 35 percent, with the highest prevalence across Sub-Saharan Africa (particularly in the East) and a number of countries across Asia. In 1991, only a select number of developing countries had undernourishment levels <5%. In 2015, many countries achieved this, particularly across Latin America, the Middle East and North Africa.

I.3 Global number of individuals undernourished

The chart below shows the total number of individuals across the world who are defined as undernourished, based on the definitions of insufficient caloric intake described above. Overall we see a falling - although variable - trend over the last few decades. The total number of undernourished has been steadily falling, particularly over the last decade. However, in 2016, the total number increased by around 40 million, reaching 815 million. The UN FAO have linked this increase in undernourishment in particular to the rising extent of conflict-affected countries (which is often a leading cause of famine), and compounded by climate-related factors such as the El Niño phenomenon (which can inflict both drought and flood conditions).1

I.4 Depth of the food deficit

The prevalence of undernourishment provides the core indicator of hunger with FAO metrics. However, this measure does not give an indication of the average severity of undernourished; it tells us how many lie below the minimum energy requirements, but not how far they lie below this line.

To provide an estimate of the intensity of undernourishment in a population, the FAO used a metric called the 'depth of the food deficit'. This measure provides an estimate of the number of calories the average individual would need in order to balance their caloric intake with energy requirements. This is calculated by measuring the difference between the average energy requirement and average caloric consumption of the undernourished population, multiplying this food deficit by the number of undernourished individuals (to give a value of the total caloric deficit of the country), and then dividing by the total population. The average intensity of the food deficit is measured in kilocalories per person per day.

We have mapped the depth of the food deficit below based on FAO data from 1991 onwards. In 2015, we see that the majority of developing countries have a food deficit below 200 kilocalories per person per day. A small selection of countries had a deficit ranging from 300-500, most in Sub-Saharan Africa. The country with the highest deficit was Haiti, at 530 kilocalories per person per day.

You can view trends of any country over time by selecting it from the map below.

I.5 Undernourishment of children

There are three key physiological measures of undernourishment and undernutrition in children. The measures discussed and visualised in the sub-sections below are:

  • Stunting - being ‘too short for one’s age’;
  • Wasting - being ‘dangerously thin for one’s height’; and
  • Underweight - low weight-for-age in children.

Too little height-for-age – Stunting

Children who are stunted are determined as having a height which falls below the median height-for-age of the World Health Organization's Child Growth Standards.

Stunting is an indicator of severe malnutrition. Unlike wasting and low weight-for-age, the impacts of stunting on child development are considered to be largely irreversible beyond the first 1000 days of a child's life. It can have severe impacts on both cognitive and physical development throughout an individual's life.2 Stunting can be caused by a range of compounding factors including nutritional intake of the child, as well as the mother during pregnancy, the recurrence of infectious diseases and infections from poor hygiene practices.

The global map of the prevalence of childhood stunting is shown below as the share of the under-5 population who are defined as stunted. Note that many countries report stunting prevalence through periodic health and demographic surveys, meaning that this data is often not available on an annual basis. The year of the latest published estimates vary by country so you may have to use the time scrollbar below to find the most up-to-date figure for a given country.

Too little weight-for-height – Wasting

Wasting is defined as being dangerously thin for one's height, and is generally a sign (especially in children) of rapid weight loss. A child is classified as wasted if his or her weight-for-height is more than two standard deviations below the median for the international reference population ages 0-59 months. The factors which contribute to this weight loss are associated with measures related to both diet and nutrition, and infection. As a result, wasting is often compounded by conditions of poor nutrition, feeding practices as well as inadequate sanitary conditions.3 Unlike stunting, wasting can be treated through improved nutritional intakes, healthcare interventions and treatment of infection.

The global map of the prevalence of childhood wasting is shown below as the share of the under-5 population. In 2015, South Sudan experienced the highest prevalence of wasting, with 22.7 percent of under-5s defined as wasted. The prevalence of wasting is typically highest across Sub-Saharan Africa and South Asia, with countries such as India, Sri Lanka, Djibouti, Sudan and Niger recording some of the highest levels (greater than 15 percent).

The share of children suffering from wasting has been declining. If we compare our global map in the early 2000s to a decade later, we see the number of countries with a prevalence greater than 15 percent has fallen. However, the nature of wasting- exemplified often by rapid weight loss- means that particular short-term events which impact food supplies can disrupt long-term trends. This is particularly prevalent in countries with poor political stability; for example, we see a large spike in childhood wasting in the Democratic Republic of Congo during the late 1990s-early 2000s during the Second Congo War.

Change of Childrens' Undernourishment in Different World Regions since 1990

Undernourishment, or the incidence of being underweight for age, can include children who are stunted, wasted or suffering from insufficient energy intake over a longer period of time.

In the chart below we see the share of children under-5 who are defined as underweight for their age across world regions since 1990. Overall, we see a steady decline at the global level, falling from around 25 percent in 1990 to 15 percent in 2015.

South Asia- despite having the highest regional prevalence- has made significant progress over the last few decades, reducing undernourishment by 20 percent from 1990-2015. The rate of undernourishment in Sub-Saharan Africa has also fallen notably, from 30 percent in 1990 to below 20 percent in 2015. Rates in East Asia, Latin America, North Africa and the Middle East are notably lower than South Asia and Sub-Saharan Africa, but have also seen significant declines, each more than halving the prevalence of undernourishment since 1990.

I.6 The Global Hunger Index (GHI)- a composite measure of progress in addressing hunger

As we have explored above, there are a number of indicators by which we can measure and track progress related to malnutrition. In order to effectively capture and track progress on hunger within a single metric, the International Food Policy Research Institute (IFPRI) have defined a score system termed the 'Global Hunger Index' (GHI). The Global Hunger Index attempts to assess the  multidimensional nature of hunger, by combining four key indicators of malnutrition into a single index score4. These four indicators are:

  • Undernourishment: the proportion of undernourished people as a percentage of the population (reflecting the share of the population with insufficient caloric intake);
  • Child wasting: the proportion of children under the age of five who suffer from wasting (low weight for their height, reflecting acute undernutrition);
  • Child stunting: the proportion of children under the age of five who suffer from stunting (low height for their age, reflecting chronic undernutrition); and
  • Child mortality: the mortality rate of children under the age of five (partially reflecting the fatal synergy of inadequate nutrition and unhealthy environments).

The index reflects scoring by country on a 100-point scale where 0 is the best score (no hunger) and 100 the worst. A score>=50 is defined as 'extremely alarming'; 35-50 as 'alarming'; 20-35 as 'serious'; 10-20 as 'moderate' and <10 as 'low'.

In the chart below we see the global map of GHI scores, with a time range of 1992, 2000, 2008 and 2016.5

Geographically we see that GHI scores are highest (i.e. worst) across Sub-Saharan Africa and South Asia. In 2016, most countries in South Asia and Sub-Saharan Africa received a score within the 'serious' or 'alarming' category. Most countries across Latin America, East & Central Asia, and Eastern Europe had low hunger levels within the 'low' or 'moderate' categories.

However, if we track progress in GHI scores through time, we see definitive improvements across all regions. In 1992, most countries across Sub-Saharan Africa and South Asia scored within the 'extremely alarming' or 'alarming' classification. By 2016, no countries remained within the top category of 'extremely alarming', and most have been downgraded to the 'serious' category. In other regions, countries have typically shifted from moderate-to-serious in 1992 down to 'low-to-moderate in 2016.

I.7 What do we know about the decline of undernourishment in the developing world over the long run?

Although it would be vital for our understanding of global development we are lacking historical data on hunger and malnourishment. The history of famines as the most extreme episodes of hunger gives some indication and is dealt with in a separate entry on Our World in Data.

Our most concrete and well-established sources of data on hunger and undernourishment begin in 1990. This is strongly related to the fact that our global progress indicators on hunger reduction are tracked based on the Millennium Development Goals (MDGs), and the subsequent Sustainable Development Goals (SDGs), which have a baseline year of 1990. During this period, the standard FAO methodology for the estimation of malnourishment has been revised for improved accuracy (for the correction see below). To our best knowledge, estimates of prevalence prior to 1990 have not been updated and published based on the revised methodology.

However, to provide some sense of how malnutrition has changed over a longer timeframe, we have extended the latest data on undernourishment backwards with FAO estimates, using previous methodologies, for 1970 and 1980. This series that shows the prevalence of undernourishment (in %) in developing countries is shown in the chart below.

The FAO maintains a consistent definition for 'developing countries'.6

Data for 1970 and 1980 has been sourced from two FAO State of Food Insecurity in the World (SOFI) reports, for 2006 and 2010. Estimates of the prevalence of undernourishment differ between these two reports. The 2006 report estimates a prevalence of 37 percent in 1970, reducing to 28 percent in 1980;7 the 2010 report instead estimates a reduction from 32.5 percent to 25 percent, respectively.8 This reflects a considerable uncertainty of these estimates and this aspect has to be taken into account as indicated in the subtitle of this chart.

Given the uncertainty in these earlier estimates, what can we say about how undernourishment has changed through time? Whilst specific figures for the level of undernourishment differ between sources, they do agree on the direction of change. Both sources report a consistent downward trend, with similar rates of reduction. The share of undernourished people in the developing world has been declining over this longer timeframe, but there are no confident figures on how many people were undernourished at each point in time.

This gives us estimated trends dating back to 1970 for undernourishment in developing countries; but do we have even earlier estimates? FAO figures of undernourishment date back to 1945, the year of its first international summit. The first edition of its 'State of Food and Agriculture' report was published in 1947 and estimated the prevalence of undernourishment in 1945 to be 50 percent.9 This does give us some useful indication of the scale of malnutrition and how this has changed through time, however, we have not included this estimate in our current series for two key reasons.

Firstly, this figure is reported for the total global population, rather than specifically addressing prevalence in developing countries.10 In early editions, figures were not defined or categorised based on income level, meaning the countries included in 1945 estimates are not the same as boundaries defined in our 1970-2015 series.

Secondly, at its initiation in 1945, the FAO had only 34 member governments involved in its food security and agriculture programme.11 The small number of UN members involved in early FAO programmes may increase levels of uncertainty surrounding data collection and estimation. Poor geographical coverage of data collection on undernourishment is likely to make 1945 estimates less reliable. By 1961, the number of member countries had increased to more than 100. By the mid-1970s, the FAO's World Committee for Food Security had 136 members. Today, the FAO has 194 member states.12

Historical perspective

The following map shows the hunger levels in Europe at the end of World War I

Hunger map of Europe, May 1919 – The New York Times13

Hunger Map of Europe (December 1918) – The New York Times0

II. Correlates, Determinants & Consequences

Correlation matrix of key food security indicators in all developing regions – FAO (2013)14

Correlation matrix of key food security indicators, all developing regions – FAO (2013)0

II.1 Correlation of Poverty and Undernourishment

II.2 Prevalence of stunting by household income

The prevalence of childhood stunting--the key indicator of chronic malnutrition--is strongly related to household income and prosperity. In the figure below, we have plotted the prevalence of stunting in children below 5 years old, by household income quintile. Shown in red is the prevalence of stunting within the lowest income quintile in each country; the highest quintile is shown in blue; and the national average in grey.15 This data is based on results of the Demographic and Health Surveys (DHS) program; the date of survey collection for each country is shown in brackets.

As shown, the prevalence of stunting in the poorest households within a given country is typically higher than those with higher incomes. This inequality between rich and poor households varies in magnitude; countries with the highest levels of stunting (i.e. those at the top of the chart below) tend to have the largest discrepancy between income levels. This difference in stunting prevalence can reach up to 50 percent in extreme cases.

II.3 Prevalence of stunting by mother's level of education

In the context of addressing malnutrition, alongside other key development measures, women's education is often highlighted as the largest determinant of positive outcomes.16

In the figure below we see the prevalence of childhood stunting by the mother's education level. Here, we have shown the two extremes: with demographics where the mother has recieved no formal education in red, and those with higher education in blue. Intermediate levels of education (whereby mothers completed primary and/or high school) are not shown, however, the average across all education levels is shown in grey.

Overall, we see the level of education of the mother is a strong determinant of childhood malnutrition. Rates of stunting are highest in families where the mother has received no formal education relative to those with higher education--this variability can exceed 50 percent between these two extremes. We also see that the prevalence of stunting in families with a mother which receives higher education is consistently lower than the average across all educational levels. Continued progress in women's educational attendance and attainment is therefore a key driver of improvements in childhood nutrition.

II.4 Prevalence of stunting in rural vs. urban settings

The residential setting of households can also play an important role in nutritional outcomes. In the chart below we have plotted the prevalence of childhood stunting in rural (shown in red), and urban (shown in blue) settings across a number of developing countries. The national average prevalence of stunting is also shown in grey.

Overall, we see that the incidence of stunting in rural households is consistently higher than in urban settings [the exception to this trend is the Dominican Republic where rates of stunting are approximately the same across household settings]. The strength of residential setting is generally less pronounced as an indicator of stunting prevalence than household income and mother's education levels; it is nonetheless still significant.

III. Data Quality & Definition

III.1 Prevalence of stunting and undernourishment

III.2 Definitions of measures of hunger and undernourishment

Here I present the definitions used by the FAO.17 I have specified when I have used a different definition above.

  • Malnutrition is defined as an 'abnormal physiological condition caused by inadequate, unbalanced or excessive consumption of macronutrients and/or micronutrients. Malnutrition includes undernutrition and overnutrition
    as well as micronutrient deficiencies.'

    • Overnourishment is defined as 'food intake that is continuously in excess of dietary energy requirements'.
    • Undernourishment is 'a state, lasting for at least one year, of inability to acquire enough food, defined as a level of food intake insufficient to meet dietary energy requirements'.

In the FAO report 'hunger' is synonymous with 'chronic undernourishment'.

Consequences of Undernourishment

The consequence of undernourishment is called Undernutrition. And the FAO names four outcomes of undernourishment, and/or poor absorption and/or poor biological use of nutrients consumed as a result of repeated infectious disease.

These are:

  • Being underweight for one’s age.
    • Underweight is defined as 'low weight for age in children, and BMI of less than 18.5 in adults'.18
  • For children, two consequences of undernourishment are:
    • being 'too short for one’s age' which is called stunting,
    • being 'dangerously thin for one’s height'  which is called wasting,
  • and being 'deficient in vitamins and minerals' which is called 'micronutrient malnutrition'.

IV. Data Sources


FAO Food Security Indicator
  • Data: Many indicators – the full list is here.
  • Geographical coverage: Global – by country and world region (some indicators are only available for developing countries).
  • Time span: Since 1990.
  • Available at: Available for download here.
  •  The whole dataset can be downloaded in one xls file.

WHO – Global Health Observatory (GHO)
  • Data: Underweight children
  • Geographical coverage: Global – by country and region.
  • Time span: Since 1990 – with projections to 2025.
  • Available at: Online here.
  •  This data is presented in the context of the Millenium Development Goals (MDG). The UN's MDG website also presents data.

International Food Policy Research Institute (IFPRI)
  • Data: Global Hunger Index and single dimensions (Prevalence of undernourishment in the population, prevalence of underweight in children under five years, under-five mortality rate)
  • Geographical coverage:  Global – by country.
  • Time span: Since 1990.
  • Available at: Online here.
  •  The Global Hunger Index is a multidimensional measure of hunger. It was first published by the 'Welthungerhilfe' but is now published by IFPR. Here is the Wikipedia entry.

World Bank – World Development Indicators


IV.1 Regular Important Publications

A regular FAO report is the The State of Food Insecurity in the World report.