Chewing and spitting – a neglected symptom?


This is a cross-post from the wonderfully informative Science of Eating Disorders blog. ScienceofEDs covers a broad range of peer-reviewed research articles related to all aspects of eating disorders. Head over and check it out! 

Eating disorders come in all shapes and sizes, but all of them are characterized by the same goal: to avoid weight gain or induce weight loss. While behaviors such as food restriction, purging and laxative abuse are relatively well studied, chewing and spitting (CHSP) is a  less studied symptom. A simple Google search, however, reveals over 1.5 million results for the term “chewing and spitting..  Results often links to blog posts or Tumblr pages where CHSP sufferers confess their guilt, disgust and obsession with the behavior.

What is chewing and spitting? How does it relate to other disordered eating behaviors, such as restrictive eating or binge eating?

Guarda AS et al. Chewing and spitting in eating disorders and its relationship to binge eating. Eating Behaviours 5 (2004) 231-239

What is CHSP?

Chewing and spitting describes the pathological eating behavior where the individual chews a variety of enjoyable foods, and spits it out to avoid undesirable consequences of weight gain (Mitchell et al, 1988). This seemingly “smart” workaround allows them to enjoy the taste of foods they usually deny themselves. However, CHSP is described as “driven and compelling,” often leading to uncontrollable episodes in which the individual chews and spits out large quantities of food. This type of behavior often results in social isolation, severe food obsession and financial difficulties.

Given the phenomenological similarities between CHSP and binge eating, CHSP was previously mostly examined in the context of bulimia nervosa (BN). While chew and spit is fairly common in patients with BN (64.5% of 275 patients with BN over the course of their lifetime), few patients engaged in the behavior continuously (Mitchell, 1985). In fact, chew and spit was considered an intermittent purging behavior used in place of self-induced vomiting or laxative abuse. A more recent surveyof individual with anorexia nervosa (AN), BN and eating disorder not otherwise specified (EDNOS) revealed that chew and spit was not limited to patients with BN (Kovacs, 2002). Patients who reported engaging in this type of behavior in the AN and EDNOS group demonstrated more disturbed eating behavior than their non-chewing and spitting counterparts.

In a study by Guarda and colleagues, , the authors set out to evaluate the prevalence and frequency of chew and spit in patients with AN, BN and EDNOS, and compare psychometrics between individuals who have this behavior compared to those who do not. Self-report questionnaires included the Beck Depression Inventory (BDI), which measures depressive symptomatology, and the Eating Disorder Inventory-2 (EDI-2) questionnaire, which measures eating disorder symptomatology. Overall, 301 patients were surveyed.

So what did they find?


1)   Overall prevalence: 34% admitted to one episode of CHSP in the month prior to admission, with 19% engaging in the behaviour several times a week (CHSP+).

2)   Overall, compared to patients who did not CHSP or did so once a week or less (CHSP-) CHSP+ patients were younger, significantly more likely to abuse diet pills, engage in excessive exercise, skipping meals and restrict fat and calories. The authors further examined if this difference in disordered eating occurred in all groups (AN, BN and EDNOS), and found that it was seen only in the AN group,. In other words, AN patients who engaged in CHSP reported more of the above behaviors than AN patients who did not. On the other hand, CHSP did not significantly alter eating behaviors in BN and EDNOS groups.

3)   Overall BDI scores were not different between CHSP- and CHSP+ patients, although CHSP+ patients were more likely to have considered suicide.

4)   There were no significant differences in mean length of stay as an inpatient, race or current employment between CHSP groups.

5)   There were no significant differences in BDI or EDI-2 in CHSP+/- patients who also engaged in binge eating.

Making sense of these results:

Contrary to previous belief, chewing and spiting is not limited to BN patients, but appears in similar frequency in patients with eating disorders in general. AN patients who engaged in CHSP tend to be more pathological in their disorder than AN patients who did not. CHSP did not influence eating behaviors of patients with BN or EDNOS. Surprisingly, CHSP is more commonly associated with other restricting eating behaviors than binging and purging.

However, as the authors noted, a limitation of this study is that they did not assess the amount of food consumed during each chew/spit episode or associated loss of control. Patients generally choose sugary or high fat food to chew and spit, hinting at a reward system deregulation that is also found in patients with binge eating disorder.  Future studies should address the macronutrient composition and amount of food consumed in a sitting as well as the individual’s state of mind to characterize this frequent eating disordered behavior and its reinforces.

Image: No. Just no. Chew Me Up - Spit Me Out, by ZahrahLeona