It’s exactly what it sounds like. "Chewing and spitting" — occasionally known as "c/s" to sufferers and "CHSP" to psychologists — is a disordered eating behavior in which individuals chew up and then spit out their food in an effort to lose weight. But it’s so much more than that. It’s hundreds of dollars spent on snacks to binge-chew. It’s the crippling guilt of wasted food. It’s swollen jaws, rotten teeth, and stomach ulcers. It’s as real and as serious as bulimia and anorexia nervosa. But, unlike these more common disordered behaviors, it is rarely talked about."A possible reason for this is that the behavior is not socially acceptable," Dr. Kathryn Kinmond, a senior lecturer from the Health, Rehabilitation and Psychology center at Manchester Metropolitan University, told me over email. CHSP is not referenced anywhere near as often as anorexia or bulimia in films and TV shows, there are no celebrities associated with it, and it often doesn’t result in pictures shocking enough for the tabloids. Most importantly, it’s harder for professionals to study, because, as Dr. Kinmond noted: "It is largely a hidden disorder, in that people are not hospitalized for chewing and spitting."In 1988, psychiatrists at Minnesota Medical School first examined chewing and spitting as a clinical feature of bulimia . Since then, a variety of studies have found that people living with anorexia, especially those with the most severe cases of the disease, also engage in the behavior. But even though 24.5% of eating disorder sufferers have been found to chew and spit, it was called a "neglected symptom" in the International Journal of Eating Disorders as recently as 2006. The U.K.’s leading eating disorder charity, Beat , told me, "It doesn’t really come into our remit at the moment," because it is considered a symptom, not a disorder in its own right.Up until 2013, chewing and spitting was featured as a symptom of Eating Disorder Not Otherwise Specified (EDNOS) in the Diagnostic and Statistical Manual of Mental Disorders. One example of EDNOS behavior in the DSM-IV was "repeatedly chewing and spitting out, but not swallowing, large amounts of food." However, EDNOS was replaced by "Other Specified Feeding or Eating Disorder" (OSFED) in the DSM-V, and there is now no mention of CHSP at all. Like Beat, health professionals continue to consider CHSP a symptom, despite the fact that online comments show that some people only chew and spit, and do not appear to also have anorexia or bulimia.