Malnutrition means poor nutrition. Most commonly this is caused by not eating enough (undernutrition) or not eating enough of the right food to give your body the nutrients it needs.

A balanced diet should provide enough nutrients like calories, protein and vitamins, to keep you healthy. Without this, you may not be getting all the nutrients you need and this can lead to malnutrition.

Malnutrition can result in:

  • unplanned weight loss
  • muscle loss
  • a low body mass index (BMI)
  • vitamin and mineral deficiencies

This can leave you feeling tired, weak and affect your ability to recover from an illness.

Symptoms of malnutrition

Malnutrition can be difficult to recognise. It can happen very gradually, which can make it very difficult to spot in the early stages.

Common signs and symptoms of malnutrition include:

  • loss of appetite and lack of interest in food or fluids
  • unplanned weight loss - this might cause clothing, rings, watches or dentures to become loose
  • tiredness or low energy levels
  • reduced ability to perform everyday tasks like showering, getting dressed or cooking
  • reduced muscle strength – for example, not being able to walk as far or as fast as usual
  • changes in mood which might cause feelings of lethargy and depression
  • poor concentration
  • poor growth in children
  • increased risk of infection, recurrent infections, taking longer to recover and poor wound healing
  • difficulty keeping warm
  • dizziness

Non-urgent advice: Speak to your GP if:

  • you have any of the symptoms of malnutrition
  • you notice a drop in weight or you've lost weight without trying

Conditions that cause malnutrition

Sometimes, medical conditions cause your body to need more nutrients. Some medical conditions can lead to your body being unable to absorb or use nutrients. These may include:

  • cancer and liver disease that can cause a lack of appetite, persistent pain or nausea
  • COPD, pulmonary fibrosis and emphysema, which cause your body to need more nutrients but can reduce your appetite
  • mental health conditions, like depression or schizophrenia, which may affect your ability to look after yourself
  • Crohn's disease, ulcerative colitis or cystic fibrosis that disrupt your body’s ability to digest food or absorb nutrients
  • burns, fractures and post major surgery, due to increased demand for nutrients
  • dementia – people with dementia may be unable to communicate their needs, may use up a lot of calories pacing or may experience a loss of appetite
  • dysphagia – a condition that makes swallowing difficult or painful
  • persistent vomiting or diarrhoea

Some types and combinations of medication can increase your risk of developing malnutrition. Always check your medicines information and speak to a healthcare professional for advice if you have a concern. Do not stop taking your medication without advice from a healthcare professional.

Other causes of malnutrition

Physical, social and ageing issues can also cause malnutrition.

Physical issues

Physical issues can contribute to malnutrition. For example:

  • if your teeth are in a poor condition, if your dentures do not fit, or if you have a sore mouth, eating can be difficult or painful
  • you may lose your appetite as a result of losing your sense of smell and taste
  • you may have a physical disability or other physical impairment that makes it difficult for you to cook or shop for food yourself
Social factors

Social issues that can contribute to malnutrition include:

  • living alone and being socially isolated
  • having limited knowledge about nutrition or cooking
  • reduced mobility
  • alcohol or drug use
  • low income or poverty
  • reliance on food banks

As we get older we might become more likely to experience malnutrition. This might be because of how we feel, and physical and social factors. The risk also increases because we're more likely to have one or more medical conditions as we get older.

Diagnosing malnutrition

A healthcare professional can assess you for malnutrition using a screening tool like ‘Malnutrition Universal Screening Tool’ (‘MUST’).

Screen yourself for malnutrition

Treating malnutrition

If you've lost weight or your appetite is poor, you can make simple changes to your meals, snacks and drinks to help treat malnutrition.

Choosing nutrient-dense food and drinks can help improve your calorie intake. This might not be suitable for everyone, especially those with other conditions like dysphagia. Ask your GP, dietitian or nurse for further advice if you're unsure.

You should speak to a healthcare professional if you've had to limit the fat and sugar you eat in the past due to a health condition like high cholesterol or diabetes.

Ways to increase your calories

Try the following ideas to help you to increase the amount of calories and protein in your diet.


  • eat ‘little and often’ – 3 small meals a day with 2-3 snacks in-between meals
  • include protein like meat, fish, chicken, eggs, beans or lentils in each meal
  • add high calorie ingredients like full cream milk, cheese, butter, ghee, olive oil and cream to meals and drinks
  • include puddings after your lunch and dinner like creamy yoghurts, custards, rice pudding, milk puddings or ice-cream
  • try ready meals if you don’t feel like cooking
  • choose nourishing milky drinks like malted drinks, hot chocolate, milky coffee and milkshakes
  • choose high sugar drinks like fruit juice, smoothies, fizzy drinks or squash (you can also add egg powder to juice to increase its nutrients)
  • try including 1 pint of full cream milk each day – you can fortify (add extra nutrients to) this by adding 4 tablespoons of dried milk powder – and use this in drinks, cooking, cereals and puddings


  • do not have drinks just before meals because this can make you feel fuller quicker
  • do not choose low fat, sugar-free, diet foods and drinks – for example skimmed milk

If you're using vegan alternatives to cheese, butter, cream or milk, try to choose the highest calorie option.

How to add extra nutrients to milk (

Watch this video to find out how to fortify your milk with milk powder. You can then use this instead of your usual milk.

How to add extra nutrients to juice (

Watch this video to find out how to fortify your juice using egg powder.

Easy ways to fortify your food

There are ways you can use every day food and drinks to fortify (add extra nutrients to) your food.


Add extra cheese or flavoured soft cheese to:

  • sauces (creamy sauces are best)
  • pasta dishes or pizza
  • soups
  • scrambled eggs or omelettes
  • mashed potatoes
  • vegetables
  • beans on toast

Add extra butter to:

  • sandwiches or toast
  • mashed potatoes
  • vegetables
  • sauces
  • baked potatoes
  • snacks like pancakes, crumpets and scones
  • biscuits or crackers
Sugar, jam and honey

Add sugar, jam or honey to:

  • puddings
  • hot drinks
  • milkshakes or smoothies
  • glazed vegetables
  • creamy yogurts
  • fruit
  • porridge or cereal
Cream, chocolate spread, peanut butter or nuts

Add cream, chocolate spread, peanut butter or nuts to:

  • porridge
  • fruit
  • sauces
  • soups
  • smoothies or milkshakes
  • snacks (toast, pancakes, crumpets, scones, waffles, rice cakes)
  • ice cream or puddings
Vegetarian and vegan food

If you follow a vegetarian or vegan diet, you can use the following foods to fortify your diet:

  • nut butters
  • vegan cheese
  • vegan cream
  • dairy free milks like oat, soya and nut milks (try to choose the sweetened options that provide the most calories)
  • hemp and pea protein powders
  • avocado
  • plant based spreads

Try to choose the highest calorie and protein options available.


Try to eat high calorie and protein snacks like:

  • crackers or oatcakes with cheese, pate, hummus or avocado
  • crumpets, scones and pancakes with butter and jam
  • thick and creamy yoghurts
  • soya yoghurts or desserts
  • milk jelly, chocolate pots and mousses
  • custard, trifle and rice pudding pots
  • dried fruit
  • nuts and seeds
  • cereal bar and flapjacks
  • mini pork pie, sausage roll, scotch egg and spring rolls
  • chocolate, biscuits, pastries and cakes
  • crisps with dip
  • fruit with chocolate spread or peanut butter

Food fortification video (

Watch this video for ideas of how to add extra nutrients to your food.

The British Dietetic Association (BDA) Malnutrition factsheet provides more useful practical advice.

Watch this video on Vimeo for more tips on how to fortify your food

Oral nutritional supplements

Oral nutritional supplements (ONS) are a range of liquid and powder products that help support better nutrition.

They contain calories, protein, vitamins and minerals to help increase your intake. They're designed to be taken alongside your diet and the ‘food first’ advice above to promote progress with your weight.

Tube feeding (enteral feeding)

Depending on how severe your symptoms are, your healthcare professional might recommend a “feeding tube”.

There are different types of tubes. Which one is best for you depends on your diagnosis and symptoms.

The most common types of feeding tube include:

  • nasogastric – through your nose and into your stomach
  • nasojejunal – though your nose and further into your digestive tract
  • percutaneous endoscopic gastrostomy (PEG) - a tube is placed directly into the stomach via your abdomen

Depending on your condition alternative routes of nutrition may be considered.

NHS Scot HS 02 01

Source: The Scottish Dietetic Prescribing Support Group

Last updated:
10 March 2023