Effects of a poor diet on the body

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

It means "poor nutrition" and can refer to:

• undernutrition – not getting enough nutrients
• overnutrition – getting more nutrients than needed

These pages focus on undernutrition in adults or children.

Read about obesity for more about the problems associated with overnutrition.

Signs and symptoms of malnutrition

Common signs of malnutrition include:

• unintentional weight loss – losing 5% to 10% or more of weight over 3 to 6 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)
• a lack of interest in eating and drinking
• feeling tired all the time
• feeling weak
• getting ill often and taking a long time to recover
• in children, not growing or not putting on weight at the expected rate

Read more about the symptoms of malnutrition.

When to see a GP

See a GP if:

• you've unintentionall
  what is a poor diet mean
  what is a bad diet