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World hunger and its causes

  • Page updated onMarch 27, 2025
World hunger and its causes
Photo: Bruno Abarca

There are many ways to understand hunger. These range from the uncomfortable or painful physical sensation caused by insufficient food energy intake, to the inability of people to meet their basic nutritional needs. Sometimes the term even ends up being equated with food insecurity, malnutrition or (simply) need and poverty. What is clear in any case is that hunger is a global problem, which is exacerbated in crises and humanitarian emergencies.

From a humanitarian perspective, it is key to try to understand world hunger as a global health and humanitarian priority, as well as the result of injustice. This, however, is not enough. It is also necessary to understand the individual and family dimension of hunger and to empathize with the experience that a person displaced by conflict, physically, mentally and emotionally exhausted, may feel. This person, starving, lives in anguish for their future and that of their sick and malnourished children, knowing that they have nothing left to sell to buy some rice and not knowing if they will be able to eat tomorrow.

What is hunger?

Hunger is a global problem that continues to increase

Far from decreasing, since 2014 world hunger has been on the rise. Today, it is estimated that around 733 million people face hunger, equivalent to one in eleven people, or more than 9% of the population. This calculation is made based on hunger as undernourishment or as a regular consumption of food that is insufficient to provide the energy needed to lead an active and healthy life.

This is not the only way to measure hunger. If we focus on regular access to adequate food, about 28.9% of the population (2.3 billion people) live in conditions of moderate or severe food insecurity. Moreover, 2.8 billion people, or more than a third of the world's population, did not have sufficient economic resources to afford a healthy diet.

Hunger and food insecurity, however, do not affect everyone equally. Africa remains the region with the highest proportion of the population affected by hunger, followed (by far) by Asia, Latin America and the Caribbean. For these reasons, the Sustainable Development Goals include number 2: Zero Hunger.

Hunger is a major cause of malnutrition and child mortality

As a result of hunger and malnutrition, millions of children die each year. It is estimated that undernutrition is associated with nearly 50% of child mortality. Of those who survive, many will live in hunger and poverty for the rest of their childhood, exposed to many more life risks and with fewer opportunities to develop their potential.

Malnutrition does not usually kill directly. Of the 4.7 million deaths in children under 5 years of age that occurred in 2021, only 97,000 were the direct result of starvation. Malnutrition, however, weakens the infant immune system and increases susceptibility and vulnerability to infections. Likewise, infections make these children weaker and more malnourished. Data from the Global Burden of Disease show that, in 2021, 2.4 million deaths in children under 5 years of age (51% of the total) were attributable to malnutrition, in its many forms.

The main nutritional risk factor for infant mortality is low birth weight. This is followed by low birth weight, acute malnutrition, chronic malnutrition, and suboptimal breastfeeding.

Child deaths attributed to malnutrition
Ritchie, 2024.

Progress against malnutrition and infections has helped reduce child mortality

Under-five mortality has declined sharply over the years. While in 1980, 13.5 million children did not reach the age of five, this figure has been falling to 9.2 million in 2000, 7.2 million in 2010, and 4.7 million in 2021. This reduction has gone hand in hand with a reduction in malnutrition in all its forms.

However, this does not mean that the problem has disappeared. This reduction has been very marked in Asia, but in sub-Saharan Africa it has barely gone from 3.9 million deaths in children under 5 years of age in 1990 to 2.9 million in 2021. All these deaths, obviously, were moreover at a very young age. As a consequence, nothing more than acute malnutrition resulted, in 2021, in 36.4 million years of life lost.

Infant deaths attributed to malnutrition, by risk factor.
Ritchie, 2024.

Food insecurity is a root cause of hunger

An obvious determinant of hunger in the world is food insecurity. Food insecurity can be defined as the lack of access to sufficient and safe food to meet nutritional needs and food preferences for a healthy and active life. There are many different ways to measure it.

Food insecurity can be measured through the experience of the people who suffer from it

FAO introduced the Food Insecurity Experience Scale (FIES) in 2016 as part of the Voices of the Hungry project. This scale allows measuring food insecurity and is used to monitor progress in the fight against hunger under the framework of the Sustainable Development Goals.

The Food Insecurity Experience Scale uses a simple questionnaire of eight questions about difficulties in accessing food due to resource constraints. Thus, the respondent is asked if in the last 12 months there has been a time when:

  1. They have worried about not having enough food to eat.
  2. They have not been able to eat healthy or nutritious foods.
  3. They have eaten a limited variety of foods.
  4. They have had to skip a meal.
  5. They have eaten less than they thought they should eat.
  6. Their home has run out of food.
  7. They have been hungry but didn't eat.
  8. They have stopped eating for an entire day.

This scale allows us to establish the severity of food insecurity, from mild (uncertainty about the ability to obtain food), moderate (lack of resources to eat a healthy diet and diet, and occasional lack of food) and severe (has gone several days without eating anything during the year or has run out of food). 

The IPC classification is another way of measuring the magnitude of food insecurity

The Integrated Food Security Phase Classification (or IPC) is another way to measure food insecurity. It is an initiative by a group of international actors used to guide policies, programs, and emergency humanitarian responses. This classification allows us to determine the severity and magnitude of the situation regarding:

  • Acute food insecurity. Food insecurity that occurs at a specific moment and with a severity that threatens lives or livelihoods.
  • Chronic food insecurity. This type persists over time, primarily due to structural causes, including seasonal factors.
  • Acute malnutrition.

The IPC acute food insecurity scale is calculated based on the analysis and consensus of experts regarding the availability of food, the ability of families to access it, whether they maintain an adequate consumption of nutrients and energy, whether the system is stable or not, the extent to which families resort to changes in livelihoods and unsustainable coping strategies (such as selling means of production and tools, reducing spending on education and health, or consuming seeds) to narrow the food gap, and the potential increase in acute malnutrition and mortality as a result of the aforementioned factors.

A famine is a situation of acute catastrophic food insecurity according to the IPC scale

The IPC scale establishes five possible levels of acute food insecurity: (1) minimal or none, (2) stressed, (3) crisis, (4) emergency, and (5) catastrophe. This fifth level is the global standard for defining the term famine in an area, which corresponds to a situation where the proportion of families at this level exceeds a certain threshold. In fact, during a famine, households experience extreme shortages of food and other basic necessities even after exhausting their coping strategies.

An area is officially considered to be in a state of famine when more than 20% of families experience extreme food shortages, over 30% of children suffer from acute malnutrition, and more than 2 adult deaths per day per 10,000 population or more than 4 child deaths per day per 10,000 children occur solely as a result of starvation or diseases related to malnutrition. Evidence (solid or reasonable) of the existence of famine in an area, once validated and reviewed by a committee of experts, should lead to declarations from those with obligations and responsibilities. A famine always requires urgent action from all parties involved to ensure humanitarian access, a rapid multisectoral response, and the cessation of conflict if it is considered a contributing factor.

Addressing hunger and malnutrition requires a multisectoral approach

Malnutrition is not only caused by food insecurity and inadequate diet. Its causes also include disease, inadequate child feeding and care practices, or lack of access to health, water, sanitation and hygiene services. Underlying these causes are other factors, such as violence, poverty, gender inequality, or human rights violations.

Essential nutrition actions
Keats, 2021.

Malnutrition can result from a lack of access to health and nutrition services

Some of the most important actions in preventing malnutrition and its consequences are provided through health services:

A solid health system is also key to establishing relevant public health policies. For example, these can address the inadequate marketing of breast milk substitutes or discourage the consumption of sugary drinks. Health authorities should also facilitate multisectoral synergy with nutrition-related interventions carried out in areas such as social protection, food systems, education, water, sanitation, hygiene, or child protection, among others.

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Adequate infant and young child feeding and care practices help prevent malnutrition

In many cases, hunger and childhood malnutrition are closely related to care practices and the difficulties faced by caregivers, who are often overwhelmed and lack sufficient support.

In this regard, for proper child development and to reduce the risk of disease, acute malnutrition and chronic malnutrition cannot be addressed solely with adequate age-appropriate nutrition. It is also essential to ensure appropriate health-seeking behavior (and access to healthcare), protection and security, education and opportunities for learning, as well as respectful, nurturing, and responsive care that meets the everyday needs of children.

Water safety, sanitation and hygiene are also critical

Water insecurity and hunger are closely interconnected. On one hand, people need water to drink and survive, and when potable water is unavailable, it can impose a significant burden, increasing their vulnerability and reducing the resources available to meet other needs, such as food, healthcare, or education. Additionally, water is essential for cooking food, maintaining personal, household, and environmental hygiene, and reducing the risk of infections. For example, lack of access to water in a humanitarian context can hinder the proper sterilization of bottles for small children who do not have access to breastfeeding, potentially leading to severe diarrhea, dehydration, and even death.

Deficiencies in water, sanitation, and hygiene often lead to an increased risk of transmission of vector-borne diseases, which thrive in unsanitary environments. These include diarrheal infections, which not only cause dehydration but also result in environmental enteric dysfunction and deficits in nutrient absorption from food. This, in turn, leads to chronic malnutrition and a decreased immune capacity to combat new infections.

Social protection systems offer protection against crises and hunger

Public policies and social protection programs are essential for safeguarding the entire population, especially the most vulnerable, in the face of economic and humanitarian crises. Through these policies and programs, it is possible to protect individuals when they lose their jobs or means of livelihood, or to empower the most vulnerable and marginalized individuals for their socioeconomic reintegration. They also ensure universal access to essential services (such as health or water) regardless of families' economic capacity, providing continuous support.

Hunger and malnutrition are exacerbated in humanitarian crises

The vulnerability space of hunger increases with conflict and displacement

Hunger occurs at the intersection of deficiencies in food security, water security, sanitation and hygiene, health and nutrition service coverage, social protection, and food and care practices. This space of vulnerability is reduced with empowerment, rights, good governance and equity. On the contrary, it increases with poverty, injustice, epidemics, conflicts, forced displacement and the effects of climate change.

In humanitarian crises and emergencies, the space of vulnerability of hunger is magnified. It is the result of the consequences of violence and the destruction of the social fabric at all levels:

  • At the macro level, conflicts, the effects of climate change and natural disasters can result in the forced displacement of entire populations who lose their livelihoods and are left at the mercy of government protection and humanitarian aid.
  • In the community, social cohesion and support networks can break down while violence increases, thereby heightening the vulnerability of families and caregivers (usually women) of young children.
  • Families can be affected by food insecurity, loss of life, lack of access to resources and services, distress and hopelessness, and domestic violence.
  • Finally, the most vulnerable individuals, including children, face an extreme risk of hunger and malnutrition in all its forms, including acute malnutrition, chronic malnutrition, micronutrient deficiencies, and overweight and obesity.

Hunger is also sometimes used as a weapon of war

In these cases, armed groups attempt to "starve" civilians by depriving them of the resources indispensable for their survival, including access to humanitarian assistance. When this violation of international humanitarian law is intentional, it can constitute a war crime, a crime against humanity and even an act of genocide.

Hunger and malnutrition

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