A landmark study into the disordered eating behaviour known as 'chew and spit' has revealed concerning levels of the practice among teens.
It's the first time the prevalence of the eating disorder has been measured, in the large scale study from psychologists at the University of Sydney.
'Chew and spit', as the name suggests, is the pathological chewing of food and spitting it out before swallowing. While not classed as a separate disorder in itself, it can often be used as a weight management technique by people with recognised eating disorders, including bulimia and anorexia nervosa.
An earlier study by the same team into the behaviour found its prevalence in adults to be 0.4 percent - slightly below the range for disorders such as bulimia or anorexia.
However, the current study of 5111 Aussie high school students found that 'chew and spit' behaviour can occur in as many as 12 percent of teenagers.
The results were published this week in Eating Disorders: The Journal of Treatment & Prevention, and lead author Phillip Aouad says they were "surprising".
"While we expected a higher prevalence in adolescents, the fairly high result is cause for concern and warrants further investigation."
He's calling for 'chew and spit' to be recognised as a separate symptom to improve clinical screening.
"If 'chew and spit' is not recognised as a formal symptom in the clinical literature, it makes it harder to identify and treat," says Aouad.
"Such a high prevalence rate in adolescents is indicative of disordered eating behaviour that cannot be ignored."
The study also recorded a distinct gender breakdown. Out fo the group of adolescents studied, 10.2 percent of males reported episodes of chew-and-spit behaviour, compared to 15.1 percent of females.
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