The prevalence of the disordered eating behaviour known as ‘chew and spit’ among teenagers has been determined for the first time, thanks to a large-scale study analysed by 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. It can often be used as a weight management technique by people with eating disorders. The behaviour, which is not recognised as a separate disorder, can follow patients across different types of eating disorders, including bulimia and anorexia nervosa.
An earlier study by the same team into the behaviour found a prevalence in adults of 0.4%, slightly below the range for disorders such as bulimia or anorexia, which occur in about 1 to 2 per cent of the population.
However, the current study found chew-and-spit behaviour can occur in as many as 12% of adolescents. The study is published in Eating Disorders: The Journal of Treatment & Prevention.
“The results surprised us,” said lead author Phillip Aouad who is completing his doctorate in the School of Psychology. “While we expected a higher prevalence in adolescents, the fairly high result is cause for concern and warrants further investigation.”
He said while the numbers in the wider adult population are relatively low, prevalence in adolescents (particularly girls) seem to be significantly higher, which is of clinical concern.
“If chew and spit is not recognised as a formal symptom in clinical literature, it makes it harder to identify and treat,” Mr. Aouad said.
“Such a high prevalence rate in adolescents is indicative of disordered eating behaviour and cannot be ignored,” Mr. Aouad said. “Without bringing this into clinical awareness, clinicians are unlikely to screen for the behaviour.”
Given that the ramifications of the behaviour are still not well understood, he said, future studies are required to examine adverse impacts.
The study on adolescents involved a longitudinal survey of 5,111 high-school students aged 11 to 19 in New South Wales, Australia. The base study of adults, published in the International Journal of Eating Disorders, involved surveying 3,047 individuals who were aged 16 or older in South Australia.
The study also found that chew-and-spit behaviour was associated with increased psychological distress and lower health-related quality of life, and an association with overeating, fasting, weight and shape concerns, laxative abuse and vomiting. Chew-and-spit behaviour was not significantly associated with either strict dieting or exercise, the study found.
For adolescents, the 12.2% prevalence was for at least one to three episodes of chew-and-spit within the past 28 days. More intense exhibitions of the behaviour were also recorded. Of all respondents, 7.7 % reported one to three episodes; 2.5% reported four to seven episodes; while 2.1% reported eight or more episodes.
The study also recorded a distinct gender breakdown. For the adolescent cohort studied, 10.2% of males reported episodes of chew-and-spit behaviour, whereas 15.1% of females reported the behaviour. The study reported responses from 35 people of other gender, with eight (22.9%) reporting chew-and-spit behaviour.