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August 26, 2021

Genes and Environment: Embracing Complexity in Eating Disorders

Genes and Environment: Embracing Complexity in Eating Disorders

Genes AND Environment; Nature AND Nurture

It’s Time to Replace those Or’s with And’s and Embrace Complexity in Eating Disorders

The 10th Annual Veritas Collaborative Symposium on Eating Disorders, co-hosted by The Emily Program, will unite healthcare professionals and eating disorders experts around this year’s theme, “Engaging Science, Unifying Voices, and Transforming Access.” In this article, Cynthia Bulik, PhD, FAED, a speaker at this year’s Symposium, explores the complexity of the genetics of eating disorders.

Truth #7: Genes and environment play important roles in the development of eating disorders.
Truth #8: Genes alone do not predict who will develop eating disorders.

— “Nine Truths About Eating Disorders

As humans, we regularly try to reduce things to their simplest form—for example, what we learned about fractions in grade school math. However, humans are not simple and neither are eating disorders. We all need to eschew all-or-nothing thinking and allow ourselves to inhabit the gray, messy space in between that leaves room for many influences to converge and define an individual’s risk for developing an eating disorder.

No matter who we are and how we identify, we can’t escape the fact that we get 50% of our genetic material from an egg and 50% from a sperm. We also can’t escape the fact that the environment influences us from conception onward (and probably even before conception if we think about environmental influences on eggs and sperm). Just explaining what makes a human is complex, let alone what causes something with complex biology and psychology like an eating disorder. How do we explain this to parents, people with lived experience, and insurance companies in terms that make sense?

One way I like to explain this is with a deck of cards analogy. Let’s say that each suit represents a particular influence—either an influence that increases your risk of developing an eating disorder or buffers (protects) you against developing an eating disorder.

• Diamonds represent genetic protective factors
• Spades represent genetic risk factors
• Clubs represent environmental risk factors
• Hearts represent environmental protective factors

With the meeting of the egg and the sperm, you get dealt your initial hand of diamonds and spades. There is nothing we can do about the diamonds and spades we are dealt or that we pass on to our offspring. We know that there will be hundreds if not thousands of genes involved with eating disorders risk, so let’s just imagine that you inherit a fairly large “dose” of spades (genetic risk factors). Those have to be counterbalanced with the diamonds that you might have inherited from your other parent (genetic protective factors). At this time, we know much less about genetic protective factors than genetic risk factors. But from the point of conception, you have your spades and diamonds.

Then we start accumulating clubs and hearts along the way. Clubs can be challenges in utero, prematurity, adverse socioeconomic experiences, loss, trauma, teasing, and other environmental events that increase the risk of developing an eating disorder or other mental health problem. But those are buffered by the hearts you accumulate like a loving family, a comfortable childhood, community, faith, and people in your life who support and encourage you.

Your ultimate risk for developing an eating disorder depends on your hand and the balance (or lack of) between risk and protective genetic and environmental factors. Now, this is oversimplified because there are many forces at work. For example, occasionally, someone will get dealt a joker—that might be a rare gene or too many copies of a gene that disrupts the whole system. Although there have been very few rare variants discovered in eating disorders, that does not mean they do not exist. There is more work to do.

Of course, there are always more factors that can influence risk and protection but conceptualizing risk in terms of these four suits can help parents and people with lived experience begin to embrace the complexity of eating disorders. It also helps to understand that there is nothing that we can do about the spades and the diamonds, but all of the work we do in treatment focuses on the critical importance of the clubs (minimizing their impact and processing their effects) and hearts (recognizing them, bringing more into your life, and realizing that you deserve them).

I will be speaking about this model in greater detail at the conference and will illustrate how the Eating Disorders Genetics Initiative (EDGI) will be embracing the complexity of eating disorders by studying both genetic and environmental factors in eating disorders across individuals from a diverse array of backgrounds. This is to ensure that our work adequately represents the way that eating disorders occur in the world so that any novel treatments that emerge from this science will be inclusive and not contribute to health disparities that have plagued our field for far too long.

We invite everyone to visit to learn more about how to participate in the EDGI study. If participating in research is something that you are not familiar with or if you have any questions, feel free to give us a call at (984) 974-3798 or send us an email at Our team can answer any questions you may have in English or Spanish.

To learn more on how nurture and nature play a role in the development of eating disorders, please register for Dr. Bulik’s presentation at this year’s Symposium, “Genes, Environment, and Eating Disorders: What the Clinician Needs to Know.” See the full agenda here. 

About the Author

Clinical psychologist Cynthia M. Bulik, PhD, FAED is the Founding Director of the University of North Carolina Center of Excellence for Eating Disorders, Distinguished Professor of Eating Disorders at the University of North Carolina at Chapel Hill, and Professor of Nutrition in the Gillings School of Global Public Health. She is also Professor of Medical Epidemiology and Biostatistics and Director of the Centre for Eating Disorders Innovation at Karolinska Institutet in Stockholm, Sweden.

Dr. Bulik received her BA from the University of Notre Dame and her MA and PhD from the University of California, Berkeley. She completed internships and post-doctoral fellowships at the Western Psychiatric Institute and Clinic in Pittsburgh, PA. Dr. Bulik has developed eating disorders programs in New Zealand, the United States, and Sweden and has active collaborations all over the world. She has published more than 600 papers and 50 chapters on eating disorders. She is the author of seven books including Crave: Why You Binge Eat and How to Stop, The Woman in the Mirror, Midlife Eating Disorders: Your Journey to Recovery, and Binge Control: A Compact Recovery Guide.

Dr. Bulik has been the recipient of numerous awards including the Eating Disorders Coalition Research Award, the Academy for Eating Disorders Leadership Awards for Research and Advocacy, the Price Family National Eating Disorders Association Research Award, and the Don and Melissa Nielsen Lifetime Achievement Award from the National Eating Disorders Association.

Dr. Bulik is past president of the Academy for Eating Disorders, past Vice-President of the Eating Disorders Coalition, and past Associate Editor of the International Journal of Eating Disorders. She serves on advisory boards of several advocacy organizations and is the founder and co-chair of the Eating Disorders Working Group of the Psychiatric Genomics Consortium.

She is passionate about advancing the science of eating disorders and translating science for the public. Read more at

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