What Are the Most Common Eating Disorders?

By Carolyn Ross, MD, MPH

Common Eating Disorders

Eating disorders constitute a spectrum of disorders from anorexia to bulimia and binge eating disorder. Binge eating disorder is the most common eating disorder in the U.S., where an estimated 1 to 5 percent of the population has been affected, according to the National Eating Disorders Association.

The National Institute of Mental Health estimates that 1.1 to 4.2 percent of women have bulimia in their lifetime. Anorexia affects 0.5 to 3.7 percent of women at some point in their lives, according to ANRED (Anorexia Nervosa and Related Eating Disorders).

It is an artificial notion to see these as discrete disorders. Many patients begin with anorexia and food restricting but may begin purging and binging. Or binge eaters can become bulimic or anorexic. The underlying focus of all of these eating disorders is very similar in that their self- evaluation is dependent on body size and shape, there is a focus on the desire to be thin which drives the behaviors and emotions, and in the end they can take over the life of the person suffering from an eating disorder. Keeping this in mind, the definitions of the various diagnoses will help to determine where the person is on this spectrum:

Anorexia Nervosa

Anorexia nervosa is associated with one of the highest mortality of any psychiatric diagnosis. Onset of the disease can be as early as 7 years with a peak between 15 to 18 years of age. Behaviors include restriction of all foods, especially those higher in calories or fat and sometimes compulsive exercise. A subset engages in self-induced vomiting or purging and/or in laxative or diuretic abuse. The classical definition of anorexia is body weight 15% below age and sex norms, loss of menstrual cycles or delayed menarche, and the reversal or stunting of pubertal development. Anorexics often develop bizarre food rituals such as having to cut their food into tiny pieces or not being able to let one food come in contact with another on their plate. As the disease progresses, an individual suffering from anorexia may experience:

• Fatigue

• Weakness

• Loss of concentration and memory

• Obsessive symptoms, including obsessive ruminations about food and obsessive body checking (e.g., pinching arms or thighs to look for body fat)

Personality characteristics associated with anorexia include perfectionism, high harm avoidance, decreased novelty seeking, self-directedness and decreased ability to view themselves as part of society. These personality traits may be present before the onset of the disease and can persist after recovery. Interestingly, the proportion of boys who are diagnosed with anorexia is much higher for childhood anorexia (26-28%) compared with those diagnosed after puberty (4-6%).

Bulimia Nervosa

Bulimia nervosa is defined by the binge/purge cycle. Binges are defined as eating large quantities of food in a small period of time. Purging behaviors can include compulsive exercise, self-induced vomiting and the use of laxatives. As noted above, it is often difficult to define what constitutes a large enough amount of food to be a binge. Therefore, focusing on the loss of control over eating may be more useful.

The onset of bulimia usually occurs after age 13 and its prevalence exceeds that of anorexia by the early adult years. Unlike anorexia, there is an increase in co-occurring substance use disorders in bulimics. The prevalence of lifetime substance use disorders in bulimics is 20 to 40 percent. Those with substance use disorders are also more likely to have social anxiety, antisocial behavior and other personality disorders, and to have a family history of substance abuse, anxiety, impulsivity and mood disorders.

Personality traits associated with bulimia are increased novelty seeking, high harm avoidance, and low self-directedness and high impulsivity.

Binge Eating Disorder and Eating Disorder Not Otherwise Specified

Binge eating disorder is more common than anorexia and bulimia combined. Roughly 60 percent of binge eaters are women with an average age of onset in the 20s, according to the Binge Eating Disorder Association.

Binge eating disorder is currently included in the DSM-IV under the diagnosis of Eating Disorder – not otherwise specified (EDNOS). This category includes those who may not strictly meet criteria for either anorexia or bulimia. Currently, EDNOS is the diagnosis with the highest prevalence, in part due to the need for revising the DSM-IV criteria to reflect, for example, that not all anorexics have amenorrhea or may have amenorrhea but have been put on the birth control pill and therefore, loss of menses cannot be documented. Proposed changes in the upcoming DSM-V, which will be released in May 2013, would categorize binge eating disorder as a separate condition.

Binge eating disorder does have specific suggested criteria for diagnosis, including the eating of large quantities of food in a small period of time, loss of control over eating and the lack of a compensatory purge. There is often remorse or shame after eating, eating very rapidly, and eating when not hungry and past the point of fullness. The types of foods consumed by binge eaters tend to be those that are lower in protein and higher in simple carbohydrates, such as snack foods and desserts. The overall calorie content of foods consumed during loss of control eating is the same as those consumed during normal meals. Weight gain, therefore, may be a function of the type of food consumed rather than the caloric value.

Accurate estimates of the number of people suffering from eating disorders are difficult to come by. As many as 10 million females and 1 million males have anorexia or bulimia, and millions more are struggling with binge eating disorder, according to the National Eating Disorders Association. Shame and stigma likely prevent many more from coming forward and asking for the help that could save their lives.

Dr. Carolyn Ross is an internationally known physician, author and speaker on addictions, obesity and eating disorders. She serves as a consultant to The Ranch’s eating disorder treatment program in Tennessee, maintains a private practice in Denver, is the author of The Binge Eating and Compulsive Overeating Workbook: An Integrated Approach to Overcoming Disordered Eating as well as The Joy of Eating Well, and also hosts a weekly radio show, The Vital Life.