Undernutrition and malnutrition

For family education. This resource is not an individual diagnosis or treatment plan. Discuss concerns with an appropriately qualified professional.

What it means

Undernutrition means inadequate energy, protein, or other nutrients for health and growth. Malnutrition is a broader term that includes nutritional imbalance; this guide focuses on childhood undernutrition. It may involve wasting, stunting, low weight, or nutrient deficiencies, and is not always obvious from appearance.

Causes and risk factors

Food insecurity, feeding difficulties, poor nutrient absorption, infection, chronic illness, and increased nutritional needs can contribute. Causes often interact. A child's family may need practical food and healthcare support alongside treatment; undernutrition should not be assumed to result from neglect.

Signs and everyday impact

Possible signs include poor growth, reduced activity, loss of muscle or fat, developmental concerns, or frequent illness. Severe acute malnutrition may include nutritional swelling, so body weight alone can hide the problem. Growth and clinical condition need professional interpretation.

Assessment and diagnosis

Clinicians assess growth measures, health, hydration, feeding, diet, and household access to nutrition. Appropriate measures and growth standards depend on age. Laboratory testing is selected according to the situation. Severe cases require assessment for complications, infection, and safe treatment setting.

Treatment and therapy

Care restores nutrition and treats contributing illness or feeding problems. Severe wasting or nutritional edema requires a structured medical nutrition program; specialized therapeutic feeding may be used when indicated. Rapid, unsupervised nutritional changes are not appropriate for every severely undernourished child. Developmental and caregiver support are part of recovery.

Support at home

Follow the prescribed feeding and follow-up plan and seek help with food access or preparation barriers. Keep safe water, food hygiene, and any prescribed medicines in mind. Do not replace recommended treatment with unverified supplements or a generic high-calorie recipe.

When to seek help

A very weak or drowsy child, swelling, dehydration, breathing difficulty, inability to feed, or signs of serious infection requires urgent care.

Questions for the care team

• What type and severity of undernutrition is present?
• Does the child need supervised treatment or hospital care?
• What practical nutrition and developmental supports are available?

Terms in plain language

• Wasting: low weight relative to length or height.
• Stunting: low length or height for age.
• Nutritional edema: swelling associated with severe malnutrition.

Podcast preparation

Use this resource to prepare a later episode: define the topic, discuss causes and signs, explain assessment, describe treatment and home supports, then close with urgent signs and a next step.

Nutritional swelling or a seemingly normal weight does not rule out serious undernutrition.

Verify current clinical guidance and obtain clinical review before public recording.

Sources

1. WHO guideline on the prevention and management of wasting and nutritional oedema (‎acute malnutrition)‎ in infants and children under 5 years - https://www.who.int/publications/i/item/9789240082830
2. Faltering Weight in Children: Parent FAQs - HealthyChildren.org - https://www.healthychildren.org/English/health-issues/conditions/Glands-Growth-Disorders/Pages/faltering-weight-in-children-parent-faqs.aspx
3. AAP Releases New Guidance on Faltering Weight in Children - HealthyChildren.org - https://www.healthychildren.org/English/news/Pages/aap-issues-new-guidance-on-faltering-weight-in-children.aspx

Sources accessed 3 October 2026.