Exploring the Main Reasons for Undernutrition and Malnutrition

November 18, 2025 •

4 min read

According to the World Health Organization, nearly half of deaths among children under five are linked to undernutrition. The main reasons for undernutrition and malnutrition are multifaceted, stemming from a complex web of socioeconomic, environmental, and health-related factors that impact individuals and communities worldwide.

Quick Summary

The root causes behind poor nutrition are complex, encompassing poverty, food insecurity, inadequate sanitation, and underlying medical conditions that impede nutrient intake or absorption.

Key Points

Poverty is a Primary Driver: Limited income restricts access to nutritious foods and contributes to a cycle of poor health and reduced productivity.
Sanitation Impacts Nutrient Absorption: Poor hygiene, unclean water, and infectious diseases like diarrhea prevent the body from properly absorbing nutrients.
Health Conditions are a Major Factor: Chronic and acute illnesses, malabsorption disorders, and mental health issues can all lead to malnutrition.
Education is Key for Prevention: Lack of knowledge, particularly maternal education, can result in poor feeding practices and low dietary diversity.
Malnutrition Includes Overnutrition: The term encompasses both undernutrition and overnutrition (obesity), with many countries experiencing a "double burden".
Global Factors Exacerbate the Problem: Conflict, climate change, and weak governance disrupt food supplies and disproportionately affect vulnerable populations.

Understanding the Complex Problem

Malnutrition is an umbrella term that describes a deficiency, excess, or imbalance in a person's intake of energy and/or nutrients. This includes undernutrition (wasting, stunting, and underweight), micronutrient-related deficiencies or excesses, and overweight or obesity. While often used interchangeably, undernutrition is a specific form of malnutrition caused by insufficient intake of energy or essential nutrients. Addressing these issues requires understanding the systemic problems that create them. From global economic inequality to local health crises, the contributing factors are deeply interconnected, affecting individuals from the earliest stages of life.

The Socioeconomic Web: Poverty and Food Insecurity

Poverty is arguably the single greatest driver of undernutrition globally. Living on limited income directly restricts a family's ability to purchase enough food, let alone a varied and nutritious diet. This economic constraint pushes vulnerable populations toward cheaper, calorie-dense but nutrient-poor foods, contributing to both undernutrition and obesity. This creates a vicious cycle: malnutrition impairs physical and cognitive development, reducing future earning potential and perpetuating poverty across generations.

High Food Costs: More than 3 billion people worldwide cannot afford a healthy diet, even when food is available. Economic shocks, conflict, and climate change drive up food prices, pushing nutritious options out of reach.
Unequal Access: Global food supplies are often adequate, but unequal distribution and poor infrastructure prevent food from reaching those who need it most. This is particularly evident in conflict zones, where supply chains are disrupted.

Health, Sanitation, and Disease

Access to clean water, proper sanitation, and hygiene (WASH) is critical for preventing malnutrition. Poor sanitation practices and unsafe drinking water are major causes of infectious diseases like diarrhea and intestinal worm infections, especially in young children. These illnesses directly impact nutritional status in several ways:

Impaired Nutrient Absorption: Diarrhea and parasitic infections damage the intestinal lining, preventing the body from absorbing vital nutrients, even when food is available.
Reduced Appetite: Frequent illness, particularly in children, reduces appetite, further decreasing nutritional intake during critical growth periods.
Loss of Nutrients: Conditions like chronic diarrhea cause the body to lose nutrients at an accelerated rate.

Inadequate Care and Knowledge

Beyond material resources, human factors play a significant role. Lack of education, especially maternal education, is consistently linked to higher rates of child malnutrition. Knowledge gaps can lead to inappropriate infant feeding practices, poor food preparation, and a lack of awareness about the importance of dietary diversity. Societal norms and gender inequality can also affect who receives food within a household, with women and girls often facing disproportionate risks of malnutrition.

Underlying Medical Conditions

Undernutrition is not always a result of insufficient food intake. A variety of medical issues can interfere with the body's ability to consume, digest, or absorb nutrients.

Digestive Disorders: Conditions like Crohn's disease and celiac disease can cause malabsorption.
Chronic Illnesses: Cancers, AIDS, and liver disease can increase caloric needs or suppress appetite.
Eating and Mental Disorders: Anorexia nervosa, bulimia, and depression can lead to severely restricted dietary intake.
Age-related Factors: Older adults may experience reduced appetite, mobility issues affecting food access, and decreased nutrient absorption.

Undernutrition vs. Malnutrition: A Comparison


Feature	Undernutrition	Malnutrition (Broad Term)
Definition	A deficiency of energy, protein, or specific micronutrients.	A deficiency, excess, or imbalance of energy and/or nutrients.
Sub-Forms	Wasting, stunting, underweight, and micronutrient deficiencies.	Includes undernutrition, overweight, obesity, and diet-related noncommunicable diseases.
Cause	Inadequate intake, poor absorption, or excessive nutrient loss.	Inadequate intake, over-consumption, or dietary imbalance.
Occurrence	More common in developing regions due to food scarcity and poverty.	Affects all countries, with a "double burden" seen in many.
Consequences	Stunted growth, weakened immunity, increased mortality risk.	Increased risk of chronic disease (e.g., diabetes), higher healthcare costs.

The Role of Systemic Inequities

At a macro level, systemic inequities drive malnutrition. Gender discrimination, for instance, means women and girls make up a disproportionate share of the chronically hungry. Conflict is another powerful factor, with 75% of the world's malnourished people residing in conflict zones. Weak governments and health systems fail to provide adequate social protection and healthcare access, exacerbating the problem. Climate change also plays a significant role, causing agricultural disruptions through extreme weather events and contributing to food insecurity. All these factors reveal that malnutrition is not just a food issue but a social, economic, and political one.

Conclusion

The main reasons for undernutrition and malnutrition are multifaceted and deeply interconnected. While immediate causes like inadequate food intake are evident, they are often symptoms of deeper issues. A potent mix of poverty, poor sanitation, infectious diseases, lack of education, and systemic inequities creates a perfect storm for nutritional deficiencies to take hold. Effective strategies must therefore address these root causes holistically. Promoting food security through economic empowerment, improving WASH infrastructure, expanding access to healthcare and education, and tackling gender inequality are all vital components of a comprehensive approach. Only by addressing this complex web of factors can the global burden of malnutrition be effectively combated. For more information on global nutrition issues, see the World Health Organization's fact sheets.

Frequently Asked Questions

Undernutrition is a specific form of malnutrition involving a deficiency of energy, protein, or other nutrients. Malnutrition is a broader term covering deficiencies, imbalances, and excesses, which also includes overweight and obesity.

Poverty causes undernutrition by limiting the purchasing power of families, forcing them to buy cheap, nutrient-poor foods or insufficient quantities. It also limits access to healthcare and education, which are vital for preventing poor nutrition.

Yes, it is possible to be overweight or obese and still be malnourished. This happens when a diet is high in calories but lacks sufficient micronutrients (vitamins and minerals), a condition often called the 'double burden of malnutrition'.

Poor sanitation and hygiene lead to infectious diseases like diarrhea, which cause nutrients to be lost before they can be absorbed by the body. This is a critical factor, especially in infants, where it can cause stunting.

Climate change and conflict create food insecurity by disrupting food production and supply chains through extreme weather, displacement, and economic instability. This leads to higher food prices and reduced access to food, particularly in vulnerable regions.

Yes, older adults are at increased risk due to factors like reduced appetite, mobility issues, social isolation, and certain medical conditions or medications that interfere with food intake and nutrient absorption.

Lack of education, particularly maternal education, can lead to poor nutritional knowledge. This results in inappropriate feeding practices, low dietary diversity, and a lack of awareness about healthy food choices, all of which contribute to malnutrition.