Anorexia or anorexia nervosa is a disorder of eating that is characterised by lack of appropriate body weight, a distorted body image, and excessive fear of gaining weight. It is a serious mental health problem, which can also prove fatal in some cases. Though it is more common in women of adolescent age, it can affect men as well as women of all ages.

Some common symptoms of anorexia include:
Excessive weight loss
Not eating enough food
Exercising excessively
Vomiting that is self-induced or use of laxatives to control calorie intake
Insomnia
Thinning of hair
Dizziness
Absence of menstrual cycle
Constipation
Dehydration
Swelling of arms or legs
Irregular heart rhythm
Low blood pressure
Dry or yellowish skin
Fatigue

The emotional and behavioural changes due to anorexia are:
Restricting food consumption by fasting or dieting
Excessive exercising
Cooking food for others but not eating them
Lack of emotion
Irritability
Eating food that is low in calories or fat
Checking weight frequently
Complaining of being fat
Withdrawing from social activities
Inability to sleep
Decreased interest in sex

The exact cause of anorexia is not clear. The causes of anorexia may be a combination of biological, environmental, and psychological factors. It includes:
Genetic predisposition
Peer pressure to be thin, especially among girls
Cultures (such as modern western culture) giving particular importance to being thin
Extreme drive to be perfect
Increased levels of anxiety causing restrictive eating

Anorexia can cause complication such as:
Osteoporosis, an increased risk of bone fractures or reduced bone tissue
Delayed growth in adolescence due to reduced levels of growth hormone
Slow movement in the intestine
Anaemia or leucopenia (low white blood cell count)
Dehydration resulting in concentrated urine
Reduced heart rate
Low blood pressure