Skip to main content

Warning notification:Warning

Unfortunately, you are using an outdated browser. Please, upgrade your browser to improve your experience with HSE. The list of supported browsers:

  1. Chrome
  2. Edge
  3. FireFox
  4. Opera
  5. Safari

Overview - Malnutrition

Malnutrition is a serious condition. It happens when your diet does not have the right amount of nutrients.

It can mean:

  • undernutrition (not getting enough nutrients)
  • overnutrition (getting more nutrients than you need)

This page focuses on undernutrition.

Signs and symptoms of malnutrition

Common signs of malnutrition include:

  • involuntary weight loss (losing 5 to 10% or more of weight over 3 to 6 months)
  • a low body weight - people with a body mass index (BMI) under 18.5 are at risk
  • lack of interest in eating and drinking
  • feeling tired all the time
  • feeling weaker
  • getting ill often and taking a long time to recover
  • In children, not growing or putting on weight as expected (faltering growth)

Use the BMI calculator to work out your BMI -

When to see your GP

Non-urgent advice: See your GP if:

  • you've unintentionally lost a lot of weight over the last 3 to 6 months
  • you have other symptoms of malnutrition
  • you're worried that someone in your care, such as a child or elderly person, is malnourished

If you're worried about a friend or another family member, encourage them to see their GP.

Your GP can check if you're at risk of malnutrition. They'll measure your weight and height, and ask about your diet and medical history.

If they think you could be malnourished, they may refer you to a specialist to discuss treatment.

Symptoms of malnutrition

Those at risk of malnutrition

Anyone can be malnourished.

But it's more common in people:

  • with long-term conditions that affect appetite, weight and how nutrients are absorbed such as Crohn's disease
  • who are isolated, can move less, or have a low income
  • with swallowing problems
  • who need extra energy, such as those recovering from a serious injury

Elderly people are more at risk. Weight loss is not an inevitable result of old age.

Causes of malnutrition

Treatments for malnutrition

Treatment depends on your general health and how malnourished they are.

The first advice is usually to:

  • eat 'fortified' foods high in calories and protein
  • snack between meals
  • have drinks that contain lots of calories

If these changes don't help, a doctor, nurse or dietitian may suggest extra nutrients. These could be nutritional drinks or supplements.

You have trouble eating soft or liquid food, other treatments may be recommended. This might involve a feeding tube that goes into your stomach or nutrition that goes into a vein.

You may need support to help with another issue such as limited mobility. If you do, you may need care at home or occupational therapy.

If a child is malnourished, the family may need advice and support to address how this may have happened.

How malnutrition is treated

Preventing malnutrition

The best way to prevent malnutrition is to have a healthy, balanced diet.

Eat a variety of foods from the main food groups, including:

  • fruit
  • vegetables
  • milk and dairy
  • bread
  • rice
  • potatoes
  • pasta
  • meat
  • fish
  • eggs
  • beans
  • other non-dairy sources of protein

Healthy eating


Speak to your GP if you have a health problem that means you're at an increased risk of malnutrition. You may have more complex dietary needs or may need to take supplements.

Content supplied by the NHS and adapted for Ireland by the HSE

Slaintecare logo
This project has received funding from the Government of Ireland’s Sláintecare Integration Fund 2019 under Grant Agreement Number 123.

Page last reviewed: 24 March 2021
Next review due: 24 March 2024