It's most prevalent among teens and adolescents.


One of the first scenes in the second episode of USA Network's new series Dare Me seems pretty typical at first: Two high school girls—main characters Beth and Addy—eating cookies on a bench outside a local market. The two chew and talk for a few seconds before both reach for their napkins and spit out a bite of cookie—and it's not a one-time thing. The girls continue talking...and chewing and spitting throughout the scene.

It's jarring, to say the least, but what exactly are they doing—and why? The method they're modeling is aptly called "chew and spit," also referred to as CHSP, and it's a behavior associated with disordered eating that involves chewing and spitting out food before swallowing it.

Until recently, CHSP was thought to be extremely rare, with less than half a percent of adults identifying with the behavior. However, according to a recent study published in Eating Disorders: The Journal of Treatment & Prevention, the incidence of chew-and-spit behavior is much higher than experts though in a previously un-researched demographic: adolescents. 

The large scale study, carried out by Australian researchers, surveyed more than 5,000 students, ranging in age from 11 to 19, from 13 schools in New South Wales, Australia. The findings showed that a whopping 12.2% (10.2% of males and 15.1% of females) reported at least one weekly chew-and-spit episode within the 28 days before they were surveyed.

But that’s not it. The study's lead author, Phillip Aouad, PhD, School of Psychology at The University of Sydney, tells Health that many of those who engaged in chew and spit also engaged in other disordered eating behaviors.

“From our study, we were able to see associations between the frequency of CHSP and other disordered eating behaviors including subjective binge eating, laxative abuse, vomiting, and fasting,” says Aouad. “It was also noted that individuals who CHSP may have lower health related quality of life and higher psychological distress.”

So, why do people use the chew-and-spit method?

Basically, CHSP is an effort to lose or control weight by monitoring (and limiting) food intake, Marney A. White, PhD, associate professor of social and behavioral sciences, and associate professor of psychiatry at Yale School of Medicine, tells Health. “People engage in this behavior to taste a particular food, but then spit it out in an effort to avoid ingesting calories.” 

At one time, chew and spit was recognized as a symptom by the American Psychiatric Association. However, in 2013 they removed it from the DSM-5 due to its seemingly low prevalence. Past studies found it had just a 0.4% prevalence—lower than other forms of disordered eating such as binge eating disorder, which is close to 3%, anorexia at 0.6%, and bulimia, which impacts about 1% of the population. 

But CHSP's low prevalence may possibly be due to lack of research on the subject. “It is an area of research that is only in recent times being brought to the forefront of medical, social, academic attention,” says Dr. Auoad. There are still many many questions that need to be answered, he adds. For example: how do we best screen for CHSP to determine the level of impact it is having on someone? How do we help someone who may be struggling with CHSP? How does CHSP fit into our understanding of eating disorders?” 

In terms of how to use this alarming new research, Dr. Auoad hopes that it will help open up the conversation, reduce the “taboo” surrounding it, and discuss it just as we do anorexia nervosa or bulimia. Additionally, he warns against “discouraging” the behavior, as many who engage in it or any other disordered behavior, there is a control struggle. “I believe the most important thing is to reduce stigma, bring attention to CHSP, and to educate people (including clinicians) about it,” he says. 

As far as treatment goes, there is currently no specific treatment for CHSP as a primary behavior, “therefore I'd expect many clinicians to approach this as they would with other eating disorders,” he says. “It is vital that we support anyone who is struggling with CHSP and for them to try and seek professional treatment for disordered eating in order to reduce the frequency of CHSP and to understand how and why it may have manifested as a behavior in the first place.”

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