Anorexia is an eating disorder and serious mental health condition.
People who have anorexia try to keep their weight as low as possible by not eating enough food or exercising too much, or both. This can make them very ill because they start to starve.
They often have a distorted image of their bodies, thinking they're fat even when they're underweight.
Men and women of any age can get anorexia, but it's most common in young women and typically starts in the mid-teens.