Eating Disorders

Latest Research on Orthorexia Nervosa (Part 2 of 3)

This blog post is the second in a three-part series on orthorexia nervosa (ON). If you haven’t read the first post, I highly recommend that you do. In Part 1, I review the latest proposed diagnostic criteria for ON and provide strategies to screen for it in your practice. This post will focus on the history and current state of the research related to ON.

While Steven Bratman, MD, MPH, coined the term ON in 1997,1 it was a 2004 Italian study that introduced ON as a “concept worthy of scientific exploration.”2

After that 2004 Italian study, a handful of published case studies appeared in the scientific literature. Case studies are a common method of introducing a condition to the field of scientific research. According to Thomas Dunn, PhD, and Bratman, “case studies often help drive early attempts at evidence-based treatment and other best practices.”1 As mentioned in the first blog post in this series, eating disorder specialist Jessica Setnick, MS, RD, CEDRD, published her own criteria for ON in 2013,3 but it wasn’t until 2015 that the first diagnostic criteria appeared in the literature.4

Most recently, in 2016, Dunn and Bratman conducted a literature review on ON.1 If you read only one research article on ON, it should be this one.

Measuring ON
The most common instrument used to detect ON is the ORTO-15, a 15-item multiple-choice questionnaire. Test takers mark whether they experience certain thoughts, feelings, or behaviors always, often, sometimes, or never. Countless variations of the ORTO-15 have been used in different countries and in different languages so there’s a lack of consistency in the international research regarding assessment tools.

Sample questions from the ORTO-15 include the following:

  • Do you spend more than three hours per day thinking about healthful food?
  • Are your eating choices conditioned by your worry about your health status?
  • Is the taste of food more important than the quality when you evaluate food?

One of the biggest and most important criticisms of the ORTO-15 is that it has produced extremely high prevalence rates in certain studies. Alvarenga and colleagues showed that the prevalence rate of ON among dietitians was of 81.9%. The ORTO-15 produces such high rates because it doesn’t adequately parse the difference between an interest in health, or extreme or atypical behaviors, and what might be considered actually pathological. Add to that the fact there are different forms of the ORTO-15 and other criticisms of the scoring system and you’re left with a largely unreliable tool.

Correctly estimating prevalence rates will remain elusive until assessment measures are improved and validated.

Diagnosis Overlap
While the current measuring tool is highly flawed, Dunn and Bratman believe there’s sufficient evidence to view ON as a condition that has distinct differences from other disorders such as anorexia nervosa or avoidant/restrictive food intake disorder.

Segura-Garcia and colleagues published important research that demonstrated a higher incidence of ON symptoms in study participants with a history of anorexia or bulimia nervosa when compared with healthy controls.5 The authors concluded that “ON seems associated both with the clinical improvement of [anorexia nervosa] and [bulimia nervosa] and the migration towards less severe forms of [eating disorders].”

Koven and colleagues provide important insights into ON and the diagnostic overlap it has with anorexia, obsessive compulsive disorder, somatic disorders, anxiety disorders, and psychotic spectrum disorders.6 This is of particular interest to dietitians working with comorbid mental health diagnoses and substantiates the proposed view of ON as a psychiatric diagnosis.

While this post is only a quick overview, it’s clear that the research related to ON is in its infancy. There are far more questions than there are answers. But an obsession with healthful eating to the point of impairment or ill health is an area in which dietitians will want to stay current.

In part 3, I’ll provide the basic steps for working with individuals who show symptoms of ON.

— Marci Evans, MS, RD, CEDRD-S, LDN, CPT, is a Food and Body Image Healer™. In addition to managing her group practice in Cambridge, Massachusetts, Marci is shaping the future of dietetics by bringing her passion and skill in the eating disorders field to students, interns, and clinicians with online trainings and clinical supervision. Connect with her at and at all social media outlets @marciRD.


  1. Dunn TM, Bratman S. On orthorexia nervosa: a review of the literature and proposed diagnostic criteria. Eat Behav. 2016;21:11-17.
  2. Donini LM, Marsili D, Graziani MP, Imbriale M, Cannella C. Orthorexia nervosa: a preliminary study with a proposal for diagnosis and an attempt to measure the dimension of the phenomenon. Eat Weight Disord. 2004;9(2):151-157.
  3. Setnick J. Academy of Nutrition and Dietetics Pocket Guide to Eating Disorders. 2nd ed. Chicago, IL: Academy of Nutrition and Dietetics; 2016.
  4. Moroze RM, Dunn TM, Craig Holland J, Yager J, Weintraub P. Microthinking about micronutrients: a case of transition from obsessions about healthy eating to near-fatal “orthorexia nervosa” and proposed diagnostic criteria. Psychosomatics. 2015;56(4):397-403.
  5. Segura-Garcia C, Ramacciotti C, Rania M, et al. The prevalence of orthorexia nervosa among eating disorder patients after treatment. Eat Weight Disord. 2015;20(2):161-166.
  6. Koven NS, Abry AW. The clinical basis of orthorexia nervosa: emerging perspectives. Neuropsychiatr Dis Treat. 2015;11:385-394.

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