From Diet to Diagnosis: Understanding Food Avoidance in Anorexia Nervosa

In a society where diet culture reigns supreme, it can be difficult to break down the messages we hear about food and eating on a daily basis. These messages, both subtle and obvious, tend to encourage and praise the avoidance of certain “bad” and “unhealthy” food groups. With or without our awareness, these messages impact our thinking and our choices about what we eat or don’t eat every day. 

Occasional dieting or food avoidance can have drastically different outcomes in people with and without eating disorders. Why is this? Increasingly, scientific evidence suggests that many eating disorders have strong genetic and neurological components. At the Columbia Center for Eating Disorders, we are trying to better understand how extreme food avoidance takes hold in people with anorexia nervosa, and what that might tell us about the development and persistence of the illness.

In what ways is anorexia nervosa different from dieting?

For people without an eating disorder, choosing to eat less or to temporarily cut out certain foods does not develop into a pursuit of extreme weight loss. However, for people with classic anorexia nervosa, what begins as cutting out some high-fat foods may quickly transition into severe caloric restriction, ultimately leading to extremely low body weight. (For those with atypical anorexia nervosa, this same behavior leads to a body weight significantly lower than the individual’s optimal weight range.) 

With the help of past study participants, we have learned that folks with eating disorders make different food choices than those without eating disorders, and that people with anorexia nervosa specifically and severely restrict calories from fat. Nonetheless, one challenge that scientists still face is understanding how occasional dieting – which is extremely common in Western culture – can, for some people, lead to life-threatening food avoidance. In other words, why does initial avoidance of a few high-fat foods sometimes, but not always, develop into the broad and severe dietary restriction characteristic of anorexia nervosa? 

One hypothesis is that for people with anorexia nervosa, the brain-based processes involved in how we learn to avoid things may become “hijacked” or impaired. This might explain why some folks who avoid a few high-fat foods in an attempt to diet gradually begin to avoid more and more foods over time, resulting in an extremely restrictive diet and low food intake overall. 

This process is referred to as overgeneralization by scientists. Research indicates that overgeneralization of avoidance behavior is present in a wide range of anxiety disorders, including phobias, panic disorder, and generalized anxiety disorder. Our team is trying to better understand whether similar processes may play a role in the extreme food avoidance seen in anorexia nervosa.

How do we study food avoidance?

To examine this question of food avoidance further, we are recruiting adolescents and adults with and without anorexia nervosa to help us better understand avoidance learning processes. Specifically, we are interested in whether individuals with this restrictive eating disorder perceive food similarly to other known threatening stimuli that are not related to food or eating. The study relies on functional magnetic resonance imaging (fMRI) to measure brain activity while participants complete a learning task on the computer. The computer task and brain imaging information will provide data critical to clarifying the potential mechanisms that underlie food avoidance in people with anorexia nervosa.

What does participation involve?

This is a 3-day study in which participants are asked to complete a variety of computer tasks and questionnaires both inside and outside of an fMRI scanner.There is no radiation involved in this type of imaging. Participation involves receiving mild electric shocks as an outcome of one of the tasks, and a research snack as the outcome of another task. Of note, the shocks are intended to be slightly uncomfortable, but not painful, and the intensity level is adjusted based on the individual’s own ratings on the first day of participation.

Participants in our patient group are eligible to receive clinical treatment through our inpatient program. Participants in our healthy control group are paid for their time and contribution.

Research in action: Come join us!

If you or someone you know is interested in participating in this study, please contact us at 646-774-8066 or

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