Eating Disorders and Twins

Is there a connection between anorexia/bulimia and twins?

Twins and eating disorders. Credit: James Woodson Creative #: 200318425-001

Is there an association between eating disorders and twins? A quick scan of headlines often seems to link the two subjects. A great deal of public attention was focused on the issue when Mary-Kate Olsen, half of the famous celebrity duo, was hospitalized for treatment of an eating disorder in June 2004. In addition, celebrity models Sia and Shane, "The Barbi Twins" battled bulimia. Did their status as twins have anything to do with their problems?

In fact, a 2014 study found that in a survey of more than two million individuals, children that were a multiple were 33 percent more likely to be diagnosed with an eating disorder. 

What is an eating disorder?

Eating disorders such as anorexia nervosa (self-starvation), bulimia nervosa (cycle of binge eating followed with purging by vomiting or use of laxatives) and binge eating (recurrent, compulsive bouts of overeating) are disorders that include extreme emotions, attitudes and behaviors surrounding weight and food issues. While anyone can be a victim of these devastating disorders, the most common sufferers are females in early to mid-adolescence. According to the National Eating Disorder Association, it is estimated that as many as 20 million females and 10 million males suffer from an eating disorder at some point.

What causes eating disorders?

They are complex conditions that arise from a combination of behavioral, emotional, psychological, interpersonal and social factors.

While scientists don't know for sure what causes a person to become unhealthy and anorexic, studying multiples have given them some clues about the genetic impact of the disorder. A study of over 1,000 sets of female twins by the Medical College of Virginia helped scientists identify the risk factors for bulimia.

Their research showed that pairs of identical (or monozygotic) twins had a much higher incidence of disorders than fraternal twins. Because identical twins share a genetic link (they have the same DNA), scientists made the connection that heredity plays a role in the disorder.

Some of the other emotional, psychological and environmental factors that cause eating disorders may make twins and multiple particularly susceptible. For example:

  • Feelings of lack of control in life
  • History of being teased or ridiculed based on size
  • Cultural norms that value people based on the physical appearance.
  • Overachieving personality

Twins are constantly being compared, and often their physical attributes are the basis for comparison and contrast. No matter how much alike they are, the public will always try to distinguish one twin as "bigger," "thinner," or "prettier." Multiples may feel driven to rebel against such labeling, or try to gain control over their physical appearance by using food to compensate. Because they are constantly compared to another individual, they may have a distorted body image, always viewing themselves in relation to their co-twin rather than having a true perception of themselves as an individual.

What are the effects of eating disorders?

Eating disorders can be fatal. When an anorexic starves herself, her body is denied the essential nutrients it needs to function. The body slows down all its processes to conserve energy, putting the victim at risk for fatigue, weakness, hair loss, muscle loss, bone deterioration and ultimately, heart failure. Bulimia leads to electrolyte imbalances, tooth decay, peptic ulcers, dehydration and can have the potential for gastric rupture, damage to the esophagus, and pancreatis. Many long-term health risks can be sustained, even after the bulimic ceases her cycle of bingeing and purging, for example: high blood pressure, high cholesterol, diabetes and heart disease.

What can parents do to protect their twins?

The National Eating Disorders Association (NEDA) makes some recommendations that parents can implement to prevent eating disorders in their children. They include:

  • Educate your kids about weightism and sexism.
  • Avoid overemphasizing beauty and body shape.
  • Discuss the value of a healthy, well-balanced diet combined with moderate exercise.
  • Identify and help children resist the ways that the media presents images based on body type.
  • Promote self-esteem and self-respect by providing opportunities and encouragement.

In addition, parents can set a good example for their kids. Don't bemoan the extra pounds of pregnancy or nitpick your body's flaws in front of your children. Avoid fad dieting, but rather implement a healthy lifestyle for the entire family.

Finally, treat your twins or multiples as individuals. Although they can't escape the comparisons inflicted on them by the public, they should feel that they are appreciated for their own merit at home. Avoid emphasizing their physical differences, especially as they grow and develop; rather, celebrate their unique features and abilities.


Berrettini, W.,"The Genetics of Eating Disorders." Psychiatry (Edgmont). 2004, pg. 18.

Goodman, A., et. al. "Associations Between Birth Characteristics and Eating Disorders Across the Life Course: Findings From 2 Million Males and Females Born in Sweden, 1975–1998." American Journal of Epidemiology. February 2014, pg. 852.

Kendler, K., et al."The structure of the genetic and environmental risk factors for six major psychiatric disorders in women. Phobia, generalized anxiety disorder, panic disorder, bulimia, major depression, and alcoholism." Archive of General Psychiatry. May, 1995. pg. 374.