The main symptom of malnutrition (undernutrition) is unintentional weight loss, although this is not always obvious.

Most people who are malnourished will lose weight, but it's possible to be a healthy weight or even overweight and still be malnourished.

For example, this can happen if you're not getting enough nutrients, such as some types of vitamins and minerals, through your diet.

You could be malnourished if:

• you unintentionally lose 5 to 10% of your body weight within 3 to 6 months
• your body mass index (BMI) is under 18.5 (although a person with a BMI under 20 could also be at risk) – use the BMI calculator to work out your BMI
• clothes, belts and jewellery seem to become looser over time

See a GP if you have unintentionally lost a lot of weight over the past few months.

If a friend or family member has lost a lot of weight, talk to them about your concerns and encourage them to get help.

Other symptoms of malnutrition include:

• reduced appetite
• lack of interest in food and drink
• feeling tired all the time
• feeling weaker
• getting ill often and taking a long time to recover
• wounds taking a long time to heal
• poor concentration
• feeling cold most of the time
• low mood, sadness and depression

See a GP if you have these symptoms. If you notice them in someone else, try to encourage them to get help.

Symptoms of malnutrition in a child can include:

• not growing or putting on weight at the expected rate (faltering growth)
• changes in behaviour, such as being unusually irritable, slow or anxious
• low energy levels and tiring more easily than other children

See a GP if you're concerned about your child's health or development at any point.