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Malnutrition is a serious condition that occurs when a person’s diet doesn't contain the right amount of nutrients.

It means "poor nutrition" and can refer to:

  • undernutrition – not getting enough nutrients
  • overnutrition – getting more nutrients than you need

This topic focuses on undernutrition. Read about obesity for more about the problems associated with overnutrition.

This page covers:

Signs and symptoms

When to see your GP

Who's at risk



Signs and symptoms of malnutrition

Common signs of malnutrition include:

  • unintentional weight loss – losing 5-10% or more of weight over three to six months is one of the main signs of malnutrition
  • a low body weight – people with a body mass index (BMI) under 18.5 are at risk of being malnourished (use the BMI calculator to work out your BMI)
  • 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 at the expected rate or not putting on weight as would normally be expected

Read more about the symptoms of malnutrition.

When to see your GP

See your GP if:

  • you've unintentionally lost a lot of weight over the last three to six months
  • you have other symptoms of malnutrition
  • you're worried someone in your care, such as a child or elderly relative, may be malnourished

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

Your GP can check if you're at risk of malnutrition by measuring your weight and height, asking about any medical problems you have, and asking about recent changes in your weight or appetite.

If they think you could be malnourished, they may refer you to a healthcare professional such as a dietitian to discuss treatment.

Who's at risk of malnutrition

Malnutrition is a common problem, affecting millions of people in the UK.

Anyone can be affected, but it's more common in:

Elderly people are particularly at risk, and weight loss is not an inevitable result of old age.

Read more about the causes of malnutrition.

Treatments for malnutrition

Treatment depends on the person’s general health and how severely malnourished they are.

The first dietary advice is usually:

  • eating "fortified" foods that are high in calories and protein
  • snacking between meals
  • having drinks that contain lots of calories 

Some people also need support to help with underlying issues such as limited mobility – for example, care at home or occupational therapy. If a child is malnourished, their family may need advice and support to address the underlying reasons why this may have happened.. 

If these initial dietary changes aren't enough, a doctor, nurse or dietitian may also suggest taking extra nutrients in the form of nutritional drinks or supplements.

If the person has difficulty eating that can't be managed by making changes such as eating soft or liquid food, other treatments may be recommended, such as:

  • a feeding tube – this can be either passed down the nose and into the stomach, or inserted directly into the stomach through the skin of the tummy
  • nutrition that is given directly into a vein

Read more about how malnutrition is treated.

Preventing malnutrition

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

You need to eat a variety of foods from the main food groups, including:

See the Eatwell Guide for more information about the types of food that should make up your diet and the proportions you should eat them in.

Speak to your GP or specialist 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.