The main symptom of anorexia is deliberately losing a lot of weight, although there are often a number of other physical and psychological signs of a problem.

Intentional weight loss

A person with anorexia will want to weigh as little as possible – much less than is healthy for their age and height. They are so afraid of gaining weight they cannot eat normally.

In an attempt to lose weight, they may:

• miss meals, eat very little or avoid eating any fatty foods
• lie about what and when they've eaten
• obsessively count the calories in food 
• lie about how much they weigh
• exercise excessively
• take appetite suppressants, such as slimming or diet pills
• make themselves vomit – you may notice they leave the table immediately after meals or have dental problems such as tooth decay or bad breath caused by the acid in vomit

They may also take laxatives or diuretics (medication that helps remove fluid from the body), although in reality these have little effect on calories absorbed from food.

Self-esteem, body image and feelings

People with anorexia often believe their value as a person hinges on their weight and how they look. They may think others will like them more or they will feel happier if they are thinner and see their excessive weight loss in a positive way.

They often have a distorted view of what they look like, thinking they look fat when they are not.

Others may try to hide how thin they are by wearing loose or baggy clothes.

Many people also practise a type of behaviour known as "body checking", which involves persistently and repeatedly:

• weighing themselves
• measuring themselves, such as their waist size
• checking their body in the mirror

People with anorexia also usually have low self-esteem or self-confidence. They may withdraw from relationships, become distant from family and friends, and lose interest in activities they previously enjoyed.

Anorexia can also affect the person's school work or how well they perform their job.

Other signs of anorexia

Eating too little for a long time can also result in physical symptoms, such as:

• bloating or constipation
• headaches
• feeling lightheaded or dizzy
• feeling very tired 
• feeling cold
• discoloured hands and feet caused by poor circulation
• dry skin
• hair loss from the scalp
• abdominal pain
• problems sleeping
• fine downy hair (lanugo) growing on the body
• brittle nails

In children with anorexia, puberty and the associated growth spurt may be delayed. They may gain less weight than expected – if any – and may be smaller than others of the same age.

Women and older girls with anorexia may stop having their periods (known as amenorrhoea, or absent periods).

Read more about the complications of anorexia nervosa.