Nutrition Diet: What are the three main types of malnutrition?

October 14, 2025 •

3 min read

According to the World Health Organization (WHO), malnutrition encompasses deficiencies, excesses, or imbalances in a person's intake of energy and/or nutrients. It is a complex global challenge with three broad groups of conditions, making it crucial to understand what are the three main types of malnutrition to address it effectively.

Quick Summary

This guide explains the primary categories of nutritional imbalance: undernutrition, overnutrition, and micronutrient deficiencies. It covers the specific forms of each type, from stunting and wasting to obesity and vitamin shortages, discussing their causes, symptoms, and potential health consequences.

Key Points

Three Main Types: Malnutrition is classified into three broad groups: undernutrition (deficiencies), overnutrition (excesses), and micronutrient-related malnutrition (imbalances in vitamins and minerals).
Undernutrition Forms: This category includes stunting (low height-for-age), wasting (low weight-for-height), and underweight (low weight-for-age), often caused by insufficient food intake and poor health.
Overnutrition Risks: Excessive calorie intake leads to overweight and obesity, which are significant risk factors for diet-related noncommunicable diseases such as heart disease and diabetes.
Hidden Hunger: Micronutrient-related malnutrition, or 'hidden hunger,' is caused by deficiencies or excesses of vitamins and minerals like iron, iodine, and vitamin A, which can affect cognitive function and immunity.
Multi-faceted Diagnosis: Healthcare professionals diagnose malnutrition using physical exams, anthropometric measurements (like BMI), blood tests, and dietary assessments.
Comprehensive Treatment: Management involves tailored nutritional plans, supplementation, and addressing underlying health or social issues. Severe cases may require hospitalization for supervised re-feeding.
Prevention is Key: Effective prevention strategies include promoting balanced diets across all life stages, exclusive breastfeeding, food fortification, and encouraging regular physical activity.

Understanding the Three Main Types of Malnutrition

Malnutrition is a state resulting from a deficiency, excess, or imbalance of nutrients, affecting health and development. It's not just about a lack of food; it also includes overconsumption of certain nutrients. The three main types are undernutrition, overnutrition, and micronutrient-related malnutrition. A balanced diet is essential for preventing all forms.

Undernutrition

Undernutrition arises from insufficient intake of calories and essential nutrients, impacting vulnerable groups like children and the elderly. Key forms include:

Wasting: Low weight-for-height due to recent weight loss.
Stunting: Low height-for-age from long-term undernutrition.
Underweight: Low weight-for-age, combining aspects of wasting and stunting.

Common causes include: Poverty, chronic illness, infections, and eating disorders.

Overnutrition

Overnutrition results from consuming too many calories and nutrients, contributing to the global rise in obesity and related noncommunicable diseases (NCDs). This leads to excessive fat accumulation.

Key features:

Overweight and obesity: Measured by BMI, caused by an energy intake-expenditure imbalance.
Diet-related NCDs: Increased risk of conditions like type 2 diabetes and heart disease.

Common causes: High-energy diets, sedentary lifestyles, and environments promoting unhealthy eating.

Micronutrient-Related Malnutrition

Also known as "hidden hunger," this type involves deficiencies or excesses of specific vitamins and minerals vital for growth and function. It can occur even with sufficient calorie intake.

Three prevalent deficiencies:

Iron deficiency: Causes anemia, fatigue, and cognitive issues.
Iodine deficiency: Affects thyroid function and development.
Vitamin A deficiency: A major cause of preventable blindness and weakened immunity in children.

Diagnosis and Treatment of Malnutrition

Diagnosis involves nutritional screening, physical examination, anthropometric measurements (like BMI), blood tests, and dietary assessment. Global criteria, such as GLIM, use physical and underlying cause factors.

Treatment is tailored to the type and severity. Undernutrition requires supervised re-feeding, often with specialized foods. Overnutrition treatment focuses on diet and lifestyle changes. Micronutrient deficiencies are addressed through supplementation, food fortification, and dietary diversity.

Prevention of Malnutrition

Prevention is crucial across all types. For undernutrition, strategies include ensuring food access, promoting healthy infant feeding, and addressing health issues. Overnutrition prevention involves promoting balanced diets and physical activity. Public health policies, education, and food fortification help combat micronutrient deficiencies.

Comparison of the Three Main Types of Malnutrition


Aspect	Undernutrition	Overnutrition	Micronutrient-Related Malnutrition
Core Issue	Insufficient intake of energy or nutrients relative to needs.	Excessive intake of energy or certain nutrients beyond needs.	Imbalance, deficiency, or excess of specific vitamins and minerals.
Associated Conditions	Wasting, stunting, underweight, anemia from deficiencies.	Overweight, obesity, heart disease, diabetes, certain cancers.	Anemia (iron), blindness (Vit A), goiter (iodine), weak bones (Vit D).
Primary Cause	Inadequate food access, poor health, poverty, infections, eating disorders.	Sedentary lifestyle, high intake of energy-dense foods, processed diets.	Lack of dietary diversity, low intake of fruits and vegetables.
Physical Appearance	Visibly thin, emaciated, or stunted growth.	Visibly overweight or obese.	Can be visibly malnourished or appear normal in weight (hidden hunger).

Conclusion

Malnutrition is a complex issue encompassing undernutrition, overnutrition, and micronutrient-related malnutrition. Many regions face a 'double burden' where under- and overnutrition coexist. Addressing this requires comprehensive strategies like ensuring food access, promoting healthy eating, and implementing effective screening and treatment. Understanding these types is key to developing targeted interventions for improved nutrition and well-being.

For more information on global nutrition strategies and health policies, visit the World Health Organization's nutrition page.

Frequently Asked Questions

Undernutrition is a deficiency in overall energy and macronutrients like proteins and carbohydrates, leading to conditions like stunting and wasting. Micronutrient malnutrition, or 'hidden hunger,' specifically refers to deficiencies in essential vitamins and minerals, which can occur even if a person gets enough calories.

Yes, it is possible to be overweight or obese and still suffer from malnutrition. This happens when a person consumes excess calories, leading to overnutrition, but lacks sufficient amounts of essential vitamins and minerals, resulting in micronutrient deficiencies.

Stunting is caused by chronic or repeated undernutrition, often linked to prolonged nutritional deprivation, poor socioeconomic conditions, inadequate maternal health, frequent illness, and insufficient feeding practices in early life.

Treatment for micronutrient deficiencies involves increasing the intake of the deficient nutrient through dietary diversification, supplementation, and food fortification. For example, salt is often iodized to combat iodine deficiency.

The 'double burden of malnutrition' describes countries or communities where both undernutrition (like stunting) and overnutrition (overweight and obesity) coexist. This is common in many low- and middle-income nations experiencing rapid dietary shifts.

Long-term consequences vary by type. Undernutrition can lead to permanent developmental delays, stunted growth, and a weakened immune system. Overnutrition increases the risk of chronic diseases like type 2 diabetes and heart disease.

Prevention strategies include promoting healthy, balanced diets across all life stages, encouraging exclusive breastfeeding for infants, fortifying staple foods with essential nutrients, and increasing nutrition education and access to healthy food.