Milestone for clinical nutrition: WHO establishes first undernutrition code for adults

For the first time, the WHO will include a code formally recognizing undernutrition in clinical settings in its 11th edition of the International Classification of Diseases (ICD-11), starting in 2027.

ICD-11 is a tool that standardizes the language used by global health professionals in diagnosing, reporting, and monitoring diseases, injuries, and causes of death.

The WHO uses the term “undernutrition” instead of “malnutrition” specifically to reference the loss of mass — based on weight, body mass index, or muscle mass — in the context of disease, inflammation, or starvation.

This change has significant implications for physicians, physician extenders, and registered dietitian nutritionists across various clinical settings.

Representatives of these fields convening under the American Society of Nutrition (ASN), the European Society for Clinical Nutrition and Metabolism (ESPEN), and the Academy of Nutrition and Dietetics (the Academy) have expressed their support for the new code.

ESPEN calls the update a “milestone for clinical nutrition.”

Meanwhile, ASN states: “This opportunity to standardize the diagnosis of undernutrition in adults with this new diagnostic coding algorithm will enhance health care practitioners’ ability to recognize the prevalence of undernutrition, identify treatments that effectively resolve undernutrition and determine the impact of undernutrition on health outcomes.”

“This undernutrition code does not exclude individuals living with overweight or obesity. However, the loss of weight or muscle in combination with the existence of clinical diagnoses that may be associated with inflammation or starvation must be present.”

Adapting new requirements

The new code 5B72 outlines specific subcategories to categorize the type of undernutrition, such as inflammation-related, disease-related, and starvation-related types. It uses coordination codes to define its severity — XS0T for Moderate and XS25 for Severe Undernutrition.

To determine whether a patient has undernutrition, clinicians can use population-specific, validated tools aligned with the new undernutrition code to improve their quality of care.

These include the Subjective Global Assessment, the Academy/American Society of Parenteral and Enteral Nutrition Indicators, the Mini Nutrition Assessment, and the Global Leadership in Malnutrition.

The code is structured to match the standards set by the Global Leadership Initiative on Malnutrition , which require clinical practitioners to identify both the cause and observable symptoms when diagnosing undernutrition.

“The implementation of a common and universal language to support the diagnosis of undernutrition will present tremendous opportunities for global cooperation to tackle this serious health challenge,” concludes ASN.

ESPEN says that the focus for 2026 will now shift to preparing official guidance and raising awareness to ensure the 2027 implementation is effective and beneficial for both patients and healthcare systems.

Highlighting the complex, shifting nature of global nutritional health crises, UNICEF recently warned that child obesity has overtaken malnutrition, marking the year 2025 as a “historic turning point.”