An Eating Disorder is when you have an unhealthy attachment to food and exercise severely that it interferes and takes over your life and can make you ill.
There are four types of Eating Disorders:
Bulimia Nervosa, Anorexia Nervosa, Binge Eating disorder and Other specified feeding or eating disorder (OSFED).
OSFED is the most common, then binge eating disorder and bulimia. Anorexia is the least common.
Factors that contribute to the onset of Eating Disorder in a western culture in which being thin is considered the ideal body shape, the portrayal of an unattainable body type in society promoted by media.
Eating disorders are more common in young women. Up to 1% of women in the UK between the ages of 15 and 30 suffer from anorexia nervosa, and about 2-3% develop bulimia nervosa.
People with Bulimia Nervosa feel at times they have lost control and subsequently eat an excessive amount of food in a very short amount of time (binging) and are then deliberately sick, with the use of laxatives (medication to help you poo), restricting what you eat, or doing too much exercise to stop weight gain.
They are concerned or distressed about their weight and body shape.
They are compensating for binge eating by repeatedly trying to control weight in extreme ways, such as purging (vomiting or using laxatives or diuretics) or exercising excessively.
Binging and purging can be a symptom of both Bulimia Nervosa and Anorexia Nervosa. However, people with Bulimia Nervosa are not extremely underweight like people with Anorexia Nervosa.
The goal that people with Anorexia Nervosa have is to lose weight. As a result of significant weight loss, they lose too much, become underweight and become unwell. They do this by severely restricting their food intake and exercising excessively.
There is a preoccupation with body shape and weight.
Some people with Anorexia Nervosa severely restrict their eating, and may also exercise excessively. Others may binge-eat (eat a large and excessive amount of food in an uncontrolled way), and then make up for overeating by purging (vomiting or using laxatives or diuretics).
Binge Eating Disorder
People with binge eating disorder eat large quantities of food, over a short period (called bingeing). This is done often very quickly and to the point of discomfort. After bingeing overwhelming feelings of guilt, shame and distress are experienced. 
Binges are often planned in advanc, and the person may buy “special” binge foods.
Other Specified feeding or eating disorder
People who are diagnosed with Other Specified feeding or eating disorder have symptoms that do not exactly fit the expected symptoms for any of the three specific eating disorders.
OSFED is every bit as serious as anorexia, bulimia, or binge eating disorder, and people diagnosed with OSFED accounts for a large percentage of eating disorders.
 NHS. (2018). Eating disorders. [Online]. Available from: https://www.nhs.uk/conditions/eating-disorders/
 Your health in mind. (2015). Eating disorders. [Online]. Available from: https://www.yourhealthinmind.org/mental-illnesses-disorders/eating-disorders
 NHS. (2017). Binge eating disorder. [Online]. Available from: https://www.nhs.uk/conditions/binge-eating/
 Beat eating disorder. (2017). Binge Eating Disorder. [Online]. Available from: https://www.beateatingdisorders.org.uk/types/binge-eating-disorder
 Beat eating disorder. (2017). Other Specified Feeding or Eating Disorder (OSFED). [Online]. Available from: https://www.beateatingdisorders.org.uk/types/osfed