Childhood acute malnutrition (wasting): evolution and challenges in its diagnosis and community management
- Page updated onApril 20, 2026
Acute malnutrition is the result of hunger and the vulnerability it creates. Childhood acute malnutrition weakens the immune system and causes developmental delays. In cases of severe acute malnutrition, there is also an increased risk of death, primarily due to heightened susceptibility to severe cases of acute diarrheal infections, acute respiratory infections, malaria, and measles. Today, it is estimated that severe acute malnutrition accounts for 20% of deaths among children under five, resulting in approximately one million deaths each year.
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The scale of the acute malnutrition problem
In 2024, 42.8 million children under 5 years of age (6.6% of the global population in that age group) suffered from acute malnutrition, of whom 12.2 million suffered from severe acute malnutrition. The most affected regions are South-East Asia and Sub-Saharan Africa, and especially areas affected by humanitarian crises resulting from climate events and conflicts (UNICEF et al., 2025)UNICEF, WHO, & World Bank. (2025). Levels and trends in child malnutrition: UNICEF/WHO/World Bank Group joint child malnutrition estimates: Key findings of the 2025 edition. World Health Organization. https://www.who.int/publications/i/item/9789240112308.
Acute malnutrition is closely linked to humanitarian crises (FAO et al., 2025)FAO, IFAD, UNICEF, WFP, & WHO. (2025). The State of Food Security and Nutrition in the World 2025: Addressing high food price inflation for food security and nutrition. FAO. https://doi.org/10.4060/cd6008en. In fact, its measure, global acute malnutrition (global acute malnutrition or GAM), which includes both moderate and severe forms, is often used as an indicator of the magnitude of an emergency. It is considered very low when below 2.5%, low when between 2.5% and 5%, medium when between 5% and 10%, high when between 10% and 15%, and very high when above 15%. Moreover, to declare a famine situation in an area, among other criteria, the prevalence of global acute malnutrition in children under 5 must exceed 30%. Although there is no official threshold for severe acute malnutrition, many organizations consider 2% to be the emergency level.
Definition and diagnosis of acute undernutrition with WHZ and MUAC
Malnutrition and undernutrition
Malnutrition can occur both from deficiency (undernutrition) and excess (obesity and overweight). Although it can affect people of all ages, the term “undernutrition” generally refers to child undernutrition, which includes chronic malnutrition (low height for age), underweight (low weight for age, a general indicator related to both acute and chronic malnutrition), or acute malnutrition.
Acute malnutrition (moderate and severe): the balance between weight and height, and nutritional edema
Acute malnutrition or, as it has historically been called, protein-energy malnutrition) encompasses two types of malnutrition: wasting and nutrition-related oedema (Bhutta et al., 2017)Bhutta, Z. A., Berkley, J. A., Bandsma, R. H. J., Kerac, M., Trehan, I., & Briend, A. (2017). Severe childhood malnutrition. Nature Reviews Disease Primers, 3, 17067. https://doi.org/10.1038/nrdp.2017.67. Although wasting and acute malnutrition are sometimes used interchangeably, this is not entirely accurate.
- On one hand there is wasting, characterised by the reduction of muscle mass and subcutaneous fat resulting from a caloric deficit, and which can be moderate when the weight-for-height or weight-for-length index is low (between 2 and 3 standard deviations below the median of the WHO child growth standard), or severe when it is very low (below 3 standard deviations) (Save the Children, 2015)Save the Children. (2015). Standardised indicators and categories for better CMAM reporting. https://resourcecentre.savethechildren.net/document/standardised-indicators-and-categories-for-better-cmam-reporting. Severe wasting has historically been known as marasmus.
- On the other hand, there is nutritional edema, historically known as kwashiorkor, which is swelling caused by fluid retention. This condition presents as bilateral swelling in the feet when the deficiency is primarily protein-based, and it can progressively spread to other parts of the body (including the face). Nutritional edema always corresponds to a case of severe acute malnutrition (never moderate). The pathophysiological mechanisms behind nutritional edema are still not well understood today.
There are, therefore, two levels of acute malnutrition: moderate acute malnutrition (MAM), which always corresponds to moderate wasting; and severe acute malnutrition (SAM), which includes both severe wasting and nutritional edema.
An alternative diagnostic method for acute malnutrition: mid-upper arm circumference (MUAC)
In children aged between 6 months and 5 years, there is another diagnostic criterion that also allows moderate and severe acute malnutrition to be defined: the mid-upper arm circumference or MUAC (Buttarelli et al., 2021)Buttarelli, E., Woodhead, S., & Rio, D. (2021). Family MUAC: A review of evidence and practice. Field Exchange, 64, 99–100. https://www.ennonline.net/fex/64/en/family-muac-review-evidence-and-practice.
The MUAC tape is a simple plastic bracelet about 35cm long that, when placed around a child's arm, allows easy measurement of the child's perimeter. According to its result, it allows to establish whether there is moderate acute malnutrition (between 115mm and 125mm) or severe acute malnutrition (less than 115mm), which is clearly indicated with colors.
MUAC was invented by a British paediatrician in Haiti in 1958 and was first used in 1969 for a population-level nutritional screening in Biafra by the ICRC. The use of a cheap, small, easy-to-transport plastic tape, very easy to use by people with little training, offered numerous advantages over the alternative in an enormously chaotic environment. In this context it was not feasible to transport scales and stadiometers to measure weight and height, and then cross-reference the resulting index with reference tables. The use of MUAC allowed the ICRC to find (and demonstrate) an alarming prevalence of 6.7% severe acute malnutrition (Glasman, 2018)Glasman, J. (2018). Measuring malnutrition: The history of the MUAC tape and the commensurability of human needs. Humanity: An International Journal of Human Rights, Humanitarianism, and Development, 9(1), 19–44. https://doi.org/10.1353/hum.2018.0001.
For years, MUAC was used as a proxy indicator for the weight-for-height index, until scientific evidence showed that this is not entirely accurate. Although they may sometimes yield equivalent results, both diagnostic methods can provide different diagnoses in other cases. Children with a MUAC indicative of acute malnutrition may have a normal weight-for-height index, and vice versa.
Today, both methods are used: weight-for-height and MUAC
Currently, the weight-for-height index is still considered the gold standard for diagnosing acute malnutrition. However, the MUAC is too simple and practical to ignore its results.
The use of MUAC allows for the detection of children at high risk of death in rural and hard-to-reach communities that would otherwise remain unidentified, unreferenced, or untreated. Although the MUAC (and its cutoff points or the ages at which its use is accepted) has a relative arbitrariness, it is a good predictor of child mortality associated with severe acute malnutrition. Therefore, it is widely used in mass screening campaigns during peak risk periods for malnutrition in these areas.
However, specialists recommend avoiding the exclusive use of MUAC in places where the weight-for-height index is also viable (for example, in health centers), due to the risk of leaving children in need of treatment undiagnosed.
Today, MUAC is almost a symbol of the fight against hunger, especially in how it has emerged from the confines of hospitals to reach tiny, under-resourced health posts. It is also a key tool for community health workers and caregivers, who even use MUAC independently to assess whether their children may be malnourished (the Family MUAC approach).
History of the management of acute malnutrition: from hospital to community
Initially, acute malnutrition was diagnosed and treated in hospitals
Until almost the end of the 20th century, acute malnutrition could only be treated in hospitals. The reason was justified. The management of child malnutrition required a high availability of beds, facilities, drinking water and specialized personnel in order to implement the ten steps that the guidelines recommended throughout the rehabilitation and stabilization phases.
Clinical protocols were effective. However, in practice, their practical application was virtually impossible in resource-limited contexts. Only 4%-10% of children with acute malnutrition were identified and diagnosed, given the limited access to hospitals. Those few who were diagnosed often presented in an advanced state of severe acute malnutrition. Furthermore, due to their secondary immunodeficiency, hospitalization exposed them to serious co-infections.
As a result, for years, the case fatality rate of hospitalized children with severe acute malnutrition remained at catastrophic levels of 20%-30% for wasting and up to 50%-60% for kwashiorkor.
During the 1970s, attempts were made to develop alternatives for outpatient management
The proposals that emerged during this period were much more economical than the hospital model. However, they did not achieve much better results.
The treatment required the administration of therapeutic milks (F-75 at the beginning and then F-100 in the rehabilitation phase), which was not easy. These products are a combination of powdered milk, sugar, cereal flour, oil, and a mixture of vitamins and minerals. Years later, there would also be a ready-to-use powdered formula. However, its preparation required specialized personnel and clean, drinkable water. Therefore, it had to be administered in community nutritional rehabilitation centers. This posed a significant problem. Having to take the children to these centers daily was an unsustainable burden for the mothers (who were almost always responsible for the care of the children).
In addition to the challenges in increasing coverage, the results in the treated children were also not sustainable. Weight gain was generally low, and often the children experienced severe relapses during treatment or after discharge.
In the 1990s, the RUTF made outpatient management of acute malnutrition feasible
The introduction in 1996 of a new product, the ready-to-use therapeutic food (RUTF), was what enabled the development of community management of acute malnutrition (CMAM) from the early twenty-first century onwards (Collins et al., 2006)Collins, S., Dent, N., Binns, P., Bahwere, P., Sadler, K., & Hallam, A. (2006). Management of severe acute malnutrition in children. The Lancet, 368(9551), 1992–2000. https://doi.org/10.1016/S0140-6736(06)69443-9.
Inspired by the cocoa spreads available on the market, scientists created a product made from oil and peanut paste that required no preparation or refrigeration, providing 500 kcal in just 92 g (in a metalized pouch). Additionally, since it contains no water, it is not susceptible to contamination. RUTF was born (along with Plumpy’Nut, the commercial brand of its first and main manufacturer: Nutriset), marking a revolution in the management of acute malnutrition.
The use of RUTF, however, is not without problems. Its use entails a significant increase in the cost of outpatient management of malnutrition. It also offers a lucrative business for now more than 20 manufacturers. In August 2024, the price for the approximate number of RUTF pouches needed for a child with severe acute malnutrition during treatment (150 units) is priced at 62.60 USD in the catalog of the UNICEF Supply Division (which supplies around 80% of the global demand for this product).
In any case, RUTF, despite its cost, has proven to be the only real therapeutic option for the community management of malnutrition. Fortunately, its cost remains much lower (not only economically but primarily in human terms) than what hospital management would entail today.
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The management and treatment of acute malnutrition today, from infants to adolescents
Once a child with acute malnutrition is diagnosed using MUAC or the weight-for-height index in the community or a health facility, they must be classified as either infants (children under 6 months) at risk of delayed growth and development, children under 5 years with moderate acute malnutrition, or children under 5 years with severe acute malnutrition (WHO, 2023)WHO guideline on the prevention and management of wasting and nutritional oedema (acute malnutrition) in infants and children under 5 years. World Health Organization. https://www.who.int/publications/i/item/9789240082830.
Management of children under 6 months of age at risk of acute malnutrition
The current approach recognises the interdependence of the mother-child dyad for their survival and wellbeing. For this reason, in the management of infants under 6 months at risk, the main objective is to detect any medical or psychological problem that could trigger severe acute malnutrition, while at the same time supporting caregivers (especially mothers) in their health (MAMI Global Network et al., 2021)MAMI Global Network, Emergency Nutrition Network, & London School of Hygiene and Tropical Medicine. (2021). MAMI Care Pathway Package (Version 3). https://www.ennonline.net/mami/resources/en/mami-care-pathway-package-version-3-2021.
The danger signs to be identified include severe acute health problems, recent weight loss, nutritional edema, medical issues that require a thorough clinical assessment, breastfeeding problems (making it ineffective), issues when using breast milk substitutes (for example, if there are concerns about inappropriate or unsafe use), or a diagnostic anthropometric value of acute malnutrition (weight-for-age or weight-for-length below 2 standard deviations, or MUAC below 110mm). In these cases, they should receive hospital care, although they may return to outpatient care as they begin to improve.
When these children are only at risk, they should receive assistance with breastfeeding, supplementation, and maternal support interventions, including mental health care, depending on the situation.
Management of moderate acute malnutrition in children 6 months to 5 years of age
When there is moderate acute malnutrition in this age group, a nutrient-dense diet is recommended, with elements available in the local market or provided through humanitarian assistance, along with a psychosocial evaluation and assessment of other concurrent health issues. In higher-risk cases, the use of specially formulated lipid-based supplements (such as Ready-to-Use Supplementary Food or RUSF, and even RUTF), solid-based supplements (such as BP-100 biscuits), or fortified mixes with added sugar, oil, and/or milk is recommended.
Management of severe acute malnutrition in children from 6 months to 5 years of age
Finally, when there is severe acute malnutrition in these age groups, treatment with 150-185 kcal/kg/day of RUTF is recommended until recovery (or with a reduction in the amount when nutritional edema resolves or emaciation becomes moderate).
In some rare cases, danger signals are detected, such as very severe edema, acute medical problems (or those requiring in-depth evaluation), lack of appetite, or failure to gain weight with normal treatment. When this occurs, inpatient treatment is recommended, although they may be referred to outpatient treatment as they improve.
Management of severe acute malnutrition in children and adolescents aged 5 to 19 years
Acute malnutrition in school-age children (over 5 years of age) and adolescents up to 19 years of age, has generally remained in the background in clinical guidelines and protocols, as it is less prevalent. However, it does occur in emergency contexts with high levels of food and nutrition insecurity, especially in contexts of conflict and siege.
At the end of 2025, the Global Nutrition Cluster published a brief technical guide with guidelines for adapting diagnostic criteria, treatment, and medical and nutritional monitoring for this age group. (Global Nutrition Cluster, 2025)Global Nutrition Cluster. (2025, December). Management of severe wasting in children and adolescents 5 to <19 years. Briefing note. https://www.nutritioncluster.net/sites/nutritioncluster.com/files/2026-01/MANAGEMENT%20OF%20SEVERE%20WASTING%20IN%20CHILDREN%20AND%20ADOLESCENTS%205%20TO%2019%20YEARS.pdf. It is recommended to use any of the following as diagnostic criteria: MUAC-for-age, weight-for-age, BMI-for-age, and the presence of bilateral edema. Regarding treatment, the main difference lies in the adjustment of simplified age-based dosing, modifying the number of daily sachets of ready-to-use therapeutic food according to the age groups of 5-9 years, 10-13 years, and 14-19 years. Attention should also be paid to other issues, such as vitamin A over-supplementation and its potential teratogenicity in adolescent pregnancies.
Coverage and innovations in the community-based management of acute malnutrition
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If we have the technical knowledge to diagnose and treat acute malnutrition in primary and outpatient health centers, why does it continue to be a major cause of child mortality? Is it only due to a lack of means and resources?
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Coverage of management of childhood acute malnutrition remains a major challenge
Today, thanks to MUAC, RUTF, and the efforts of so many health and nutrition professionals and community health workers, the treatment of acute malnutrition is carried out mainly on an outpatient basis. As a result, coverage has increased. However, it remains severely insufficient (Rogers et al., 2015)Rogers, E., Myatt, M., Woodhead, S., Guerrero, S., & Alvarez, J. L. (2015). Coverage of community-based management of severe acute malnutrition programmes in twenty-one countries, 2012–2013. PLOS ONE, 10(6), e0128666. https://doi.org/10.1371/journal.pone.0128666. Although assessing treatment access coverage is difficult (requiring studies such as SQUEAC surveys) and is done less frequently than would be desirable, it is estimated that 2 out of every 3 children with severe acute malnutrition do not have access to the treatment they need.
What are the main barriers? The distances that must be covered to access healthcare (even at a health post or centre rather than a hospital), weaknesses in mobile and community outreach health services, lack of information or awareness about acute malnutrition, and problems in the procurement and supply of RUTF, which many governments still do not cover (Global Nutrition Cluster, 2025)Global Nutrition Cluster. (2025, May). Interim programmatic adaptations for wasting programming in resource-constrained settings. https://www.nutritioncluster.net/resources/interim-programmatic-adaptations-wasting-programming-resource-constrained-settings. Addressing all these problems requires coordinated action among multiple actors (FAO et al., 2020)FAO, UNHCR, UNICEF, WFP, & WHO. (2020). Global action plan on child wasting: A framework for action to accelerate progress in preventing and managing child wasting and the achievement of the Sustainable Development Goals. UNICEF. https://www.unicef.org/media/96991/file/Global-Action-Plan-on-Child-Wasting.pdf.
Innovations in the management of childhood acute malnutrition for increased coverage
A number of innovations are being researched and implemented to further evolve the management of acute malnutrition towards a model even better suited to community-based care (Action Against Hunger, 2021)Action Against Hunger. (2021). Technical positioning on evolution of CMAM implementation — Update January 2021. https://knowledgeagainsthunger.org/wp-content/uploads/2021/02/Technical-Positioning-Evolution-CMAM-Implementation-SignedVF.pdf. These potential innovations include:
- The simplification and integration of protocols for managing moderate and severe acute malnutrition into a single protocol. This allows personnel to achieve equal or more effective performance with less training and supervision.
- The combination of using MUAC with a weight-for-age index that allows for better diagnosis (without requiring the transport of a height measuring device).
- The reduction in RUTF doses. This would allow for a decrease in its usage costs and increase its availability for more patients.
- The use of digital tools for the diagnosis and management of malnutrition.
- The inclusion of the management of uncomplicated moderate and severe acute malnutrition among the tasks of community health workers.
To date, the most promising innovation appears to be the integration of acute malnutrition management into the activity package of community health workers (Action Against Hunger, 2024)Action Against Hunger. (2024). Community health workers addressing acute malnutrition: From idea to reality. https://accioncontraelhambre.org/sites/default/files/documents/chws_addressing_acute_malnutrition._from_idea_to_reality.pdf. These volunteer workers were already diagnosing and treating common childhood illnesses such as acute diarrhoea, respiratory infections, and malaria, as well as carrying out health education and promotion activities. Recent research by Action Against Hunger shows that these programmes achieve performance and cure rates similar to those of nursing staff in health centres, at lower cost and with greater coverage. In 2023, WHO included this as a recommendation in its new guidelines, on the condition that these volunteers are integrated as health workers into the health system with adequate training and supervision (WHO, 2023)WHO guideline on the prevention and management of wasting and nutritional oedema (acute malnutrition) in infants and children under 5 years. World Health Organization. https://www.who.int/publications/i/search?query=9789240082830.
References
- Action Against Hunger. (2021). Technical positioning on evolution of CMAM implementation — Update January 2021. https://knowledgeagainsthunger.org/wp-content/uploads/2021/02/Technical-Positioning-Evolution-CMAM-Implementation-SignedVF.pdf
- Action Against Hunger. (2024). Community health workers addressing acute malnutrition: From idea to reality. https://accioncontraelhambre.org/sites/default/files/documents/chws_addressing_acute_malnutrition._from_idea_to_reality.pdf
- Bhutta, Z. A., Berkley, J. A., Bandsma, R. H. J., Kerac, M., Trehan, I., & Briend, A. (2017). Severe childhood malnutrition. Nature Reviews Disease Primers, 3, 17067. https://doi.org/10.1038/nrdp.2017.67
- Buttarelli, E., Woodhead, S., & Rio, D. (2021). Family MUAC: A review of evidence and practice. Field Exchange, 64, 99–100. https://www.ennonline.net/fex/64/en/family-muac-review-evidence-and-practice
- Collins, S., Dent, N., Binns, P., Bahwere, P., Sadler, K., & Hallam, A. (2006). Management of severe acute malnutrition in children. The Lancet, 368(9551), 1992–2000. https://doi.org/10.1016/S0140-6736(06)69443-9
- FAO, IFAD, UNICEF, WFP, & WHO. (2025). The State of Food Security and Nutrition in the World 2025: Addressing high food price inflation for food security and nutrition. FAO. https://doi.org/10.4060/cd6008en
- FAO, UNHCR, UNICEF, WFP, & WHO. (2020). Global action plan on child wasting: A framework for action to accelerate progress in preventing and managing child wasting and the achievement of the Sustainable Development Goals. UNICEF. https://www.unicef.org/media/96991/file/Global-Action-Plan-on-Child-Wasting.pdf
- Glasman, J. (2018). Measuring malnutrition: The history of the MUAC tape and the commensurability of human needs. Humanity: An International Journal of Human Rights, Humanitarianism, and Development, 9(1), 19–44. https://doi.org/10.1353/hum.2018.0001
- Global Nutrition Cluster. (2025, May). Interim programmatic adaptations for wasting programming in resource-constrained settings. https://www.nutritioncluster.net/resources/interim-programmatic-adaptations-wasting-programming-resource-constrained-settings
- Global Nutrition Cluster. (2025, December). Management of severe wasting in children and adolescents 5 to <19 years. Briefing note. https://www.nutritioncluster.net/sites/nutritioncluster.com/files/2026-01/MANAGEMENT%20OF%20SEVERE%20WASTING%20IN%20CHILDREN%20AND%20ADOLESCENTS%205%20TO%2019%20YEARS.pdf
- MAMI Global Network, Emergency Nutrition Network, & London School of Hygiene and Tropical Medicine. (2021). MAMI Care Pathway Package (Version 3). https://www.ennonline.net/mami/resources/en/mami-care-pathway-package-version-3-2021
- Rogers, E., Myatt, M., Woodhead, S., Guerrero, S., & Alvarez, J. L. (2015). Coverage of community-based management of severe acute malnutrition programmes in twenty-one countries, 2012–2013. PLOS ONE, 10(6), e0128666. https://doi.org/10.1371/journal.pone.0128666
- Save the Children. (2015). Standardised indicators and categories for better CMAM reporting. https://resourcecentre.savethechildren.net/document/standardised-indicators-and-categories-for-better-cmam-reporting
- UNICEF, WHO, & World Bank. (2025). Levels and trends in child malnutrition: UNICEF/WHO/World Bank Group joint child malnutrition estimates: Key findings of the 2025 edition. World Health Organization. https://www.who.int/publications/i/item/9789240112308
- World Health Organization. (2023). WHO guideline on the prevention and management of wasting and nutritional oedema (acute malnutrition) in infants and children under 5 years. World Health Organization. https://www.who.int/publications/i/item/9789240082830
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Abarca, B. (April 20, 2026). Childhood acute malnutrition (wasting): evolution and challenges in its diagnosis and community management. Salud Everywhere. https://saludeverywhere.com/en/health-in-humanitarian-crises/acute-malnutrition/