Former Big Brother contestant Kenneth Tong has been tweeting that women should aspire to "managed anorexia". Celebrities are already condemning him, but is there such a thing?

What is anorexia?

Anorexia nervosa has a higher risk of killing you than many other mental health disorders. It is not extreme dieting, but a mental health problem defined by a distorted body image and weight at least 15% under what is considered normal for the individual. Studies show that people with anorexia are 10 times more likely to die than other people of their age and sex.

What are the symptoms?

Dieting is so common among teenagers that parents rarely suspect anorexia. People with it will be scared about getting fat, and preoccupied with their body. They miss meals and develop strategies to look as though they are eating by moving food around the plate or saying they've already eaten elsewhere. They will deny they have a problem. They may throw up, use laxatives or exercise constantly. They may stop having periods, develop downy hair on their faces and upper bodies, and feel cold, dizzy and tired. Long-term anorexia causes thinning of the bones, heart problems and kidney failure.

There is a screening called the Scoff questionnaire – two or more yeses to the following questions suggest there is a problem: Do you ever make yourself sick because you feel uncomfortable? Do you worry you have lost control over how much you eat? Have you recently lost more than one stone in a three-month period? Do you believe yourself to be fat when others say you are too thin? Would you say that food dominates your life?

What causes it?

No one knows. It is more common among societies where thinness is admired and in professions where it is essential, such as ballet and modelling. Low self-esteem, a history of abuse, and being teased about your body may make you more susceptible, and there may be a genetic influence. There is evidence that premature baby girls are at increased risk.

How can it be treated?

People with anorexia need to put on weight and change their relationship with food. Research suggests three quarters of people have been ill for between one and 15 years. One study found that about 43% of people recover, 36% improve, 20% have a chronic problem and 5% die from anorexia.

Unfortunately, there isn't much evidence for what works. Family therapy may help, and some people may need to be admitted to hospital. Teenagers not at risk of dying can do better in specialist outpatient clinics.

When should I see my doctor?

If you answered two yeses to the Scoff questionnaire. Anorexia is not a manageable way of life. It's a disorder that can kill you.