Understanding Malnutrition: What does wasted mean in nutritional status?

October 7, 2025 •

3 min read

According to the World Health Organization, 45 million children under 5 were estimated to be wasted globally in 2022, a serious and life-threatening condition. This acute form of undernutrition, where low weight for height is observed, helps define and quantify a child's nutritional status.

Quick Summary

Wasting is low weight-for-height, an indicator of acute malnutrition caused by insufficient nutrition and illness. It is measured using anthropometric tools like Weight-for-Height Z-score and Mid-Upper Arm Circumference, and is distinct from stunting. The condition is treatable with therapeutic foods and medical care.

Key Points

Definition of Wasting: Wasting, or acute malnutrition, is indicated by a low weight-for-height ratio, showing recent and often severe weight loss.
Measurement Tools: Health professionals use Weight-for-Height Z-score (WHZ), Mid-Upper Arm Circumference (MUAC), and check for bilateral pitting oedema to assess wasting.
Wasting vs. Stunting: Wasting is an indicator of acute, or recent, malnutrition, whereas stunting reflects a chronic, long-term state of undernutrition.
Key Causes: Wasting is often caused by a combination of factors, including inadequate food intake, frequent infections, poor sanitation, and maternal health issues.
Severity and Risk: Severe wasting is the deadliest form of undernutrition, significantly increasing a child's risk of death from common childhood illnesses.
Effective Treatment: Treatment for wasting involves using specialized therapeutic foods like RUTF for uncomplicated cases and providing inpatient medical care for severe or complicated cases.
Prevention Focus: Strategic interventions, especially during the critical first 1,000 days of a child's life, are essential for preventing the onset of wasting.

Wasting is a critical measure used in nutritional assessments, particularly among children under five, to identify acute undernutrition. It is defined by low weight for a person's height, indicating a recent and often severe weight loss. While the term 'malnutrition' is broad and covers both over- and undernutrition, wasting refers specifically to a sudden and significant deficiency that poses an immediate risk to health and survival. The causes range from food shortages and infection to poor care practices, all of which contribute to this dangerous form of malnutrition.

The Definition of Wasting and Acute Malnutrition

Wasting, also known as acute malnutrition, is characterized by significantly low body mass relative to height, typically resulting from a rapid loss of muscle and fat. This condition is often triggered by inadequate food intake or severe illnesses like diarrhea or measles. Severe wasting is particularly dangerous, increasing a child's risk of mortality by up to 11 times. In some cases of severe acute malnutrition, nutritional oedema (swelling in the extremities) may also be present, which is also a sign of severe malnutrition. Wasting is a significant global health issue, contributing to a large percentage of deaths in young children in certain regions.

How is Wasting Measured? Anthropometric Assessment

To accurately identify and quantify wasting, anthropometric measurements are used and compared against WHO global growth standards. Key indicators include:

Weight-for-Height Z-score (WHZ): This compares a child's weight to the standard for their height. A WHZ score more than two standard deviations below the median indicates wasting, while a score more than three below the median indicates severe wasting.
Mid-Upper Arm Circumference (MUAC): This measurement of the upper arm circumference using a colored tape is a quick screening tool. A MUAC below 125mm suggests moderate acute malnutrition, and below 115mm indicates severe acute malnutrition.
Bilateral Pitting Oedema: This clinical sign of severe acute malnutrition is identified by pressing on both feet; if an indentation remains, oedema is present.

Causes and Contributing Factors of Wasting

Wasting results from a combination of factors:

Inadequate Food Intake: Insufficient food or lack of essential nutrients is a major cause. Poverty and low income limit access to nutritious food.
Infections and Illness: Frequent illnesses increase energy needs and hinder nutrient absorption.
Poor Maternal Health and Nutrition: A mother's health before and during pregnancy and breastfeeding impacts a child's risk.
Environmental Factors: Unsafe water and poor sanitation lead to recurrent infections. Conflict, climate change, and food insecurity also contribute.
Inappropriate Feeding Practices: Poor breastfeeding and complementary feeding practices, particularly in early childhood, are significant factors.

Comparison: Wasting, Stunting, and Underweight

Wasting is distinct from other forms of undernutrition:


Feature	Wasting	Stunting	Underweight
Indicates	Acute (recent) undernutrition	Chronic (long-term) undernutrition	Composite of both wasting and stunting
Measurement	Low weight-for-height (WHZ < -2 SD)	Low height-for-age (HAZ < -2 SD)	Low weight-for-age (WAZ < -2 SD)
Cause	Recent and severe calorie/nutrient deficit, often due to infection or famine.	Prolonged poor nutrition and repeated infections over time.	Combination of short-term and long-term undernutrition.
Consequences	High risk of morbidity and mortality.	Impaired cognitive and physical development; irreversible.	Reflects overall nutritional status; can be both stunted and wasted.
Reversibility	Reversible with proper intervention	Irreversible once established	Can be improved by addressing underlying stunting or wasting

How Wasting is Treated

Wasting is treatable with prompt and appropriate interventions following WHO and UNICEF guidelines.

Community-Based Management: Children with uncomplicated severe acute malnutrition can be treated as outpatients using Ready-to-Use Therapeutic Food (RUTF), a high-energy, nutrient-dense paste.
Inpatient Care: Children with complicated severe acute malnutrition require hospitalization for medical complications. Treatment involves stabilizing the child, addressing medical issues, and gradually introducing therapeutic feeding.
Addressing Underlying Issues: Effective treatment includes improving access to clean water, promoting hygiene, and enhancing food security. Long-term prevention strategies are crucial.

Conclusion

In nutritional status, 'wasted' refers to low weight relative to height, indicating acute undernutrition. It signals recent hardship and carries a high risk of mortality, especially in young children. Early detection using anthropometric measurements like WHZ and MUAC, combined with proven therapeutic feeding protocols, is essential for treatment and prevention. Addressing wasting is vital for improving child health and development. For more information, visit the UNICEF website.

Frequently Asked Questions

The primary causes of wasting are inadequate food intake and severe, recurrent infections. These factors lead to a rapid depletion of body fat and muscle tissue, causing the low weight-for-height characteristic of the condition.

Wasting is a measure of acute malnutrition, reflecting recent and severe weight loss (low weight-for-height). Stunting is a measure of chronic malnutrition, reflecting a history of poor nutrition and resulting in a child being too short for their age (low height-for-age).

MUAC is a simple, effective, and quick screening tool to identify children with acute malnutrition. It is particularly useful in community and emergency settings where more complex anthropometric measurements might be difficult to perform.

Yes, wasting is reversible with proper and timely nutritional and medical interventions. Correcting nutritional deficiencies and treating underlying infections are key to recovery. However, the effects of severe and untreated wasting can linger and have long-term consequences.

Children with severe wasting and complications often require inpatient treatment following a protocol established by WHO, which includes stabilization, treating medical issues like hypoglycemia, and gradually introducing therapeutic feeding. For uncomplicated cases, community-based management with RUTF is effective.

While wasting is most commonly discussed in relation to child malnutrition, it can affect people of all ages. For example, elderly individuals, those with chronic illnesses, or those with eating disorders can also experience muscle wasting due to undernutrition.

Yes, a child can be both stunted (chronically undernourished) and wasted (acutely undernourished), a condition sometimes referred to as wasted-stunted or concurrently malnourished. This combination indicates a more severe and complex nutritional problem.