Overweight teenagers chew slower and spend less time eating compared with their thinner peers, a University of Otago study has found.

Lead author Dr Ghassan Idris (left), of Otago’s Sir John Walsh Research Institute and Queensland Children’s Hospital, describes the results as “unexpected” but says they open new pathways of research into youth weight-management interventions.

For the study, recently published in Pediatric Obesity, the research team recruited 42 15-year-olds (21 in a healthy weight range and 21 who were overweight), and assessed their chewing features over one evening, including an evening meal, in their homes.

Jaw muscle contractions were recorded using a small wireless sensor device connected to a smartphone datalogger, developed by Otago’s Professor Mauro Farella. The nature of the device allowed recording of chewing features and eating occasions in a natural environment, compared to previous studies conducted in a laboratory setting.

“Our findings showed that the larger adolescents had a slower chewing pace and spent a shorter amount of time eating compared with leaner adolescents – about 35 per cent less time.

“These findings were unexpected when compared to previous questionnaires and lab-based studies, which have indicated that children who are overweight tend to chew food at a faster pace than their healthy-weight counterparts.

“Our findings also contrasted with our previous ones collected from adults, where we could not establish a relationship between the way people eat and their body mass index,” Dr Ghassan says.

He believes the study, while small, provides impetus for further work testing the effectiveness of changing eating behaviour as a weight-management intervention in youth.

“Future research is needed to identify how the way we eat can result in weight gain, or affects digestion, and eventually to explore potential application in weight control behavioural therapies, such as recommending chewing food for a longer time in young people.”

* This study was carried out within an interdisciplinary team with expertise in Dentistry (Dr Ghassan Idris, Professor Mauro Farella, and Dr Christopher Robertson), Human Nutrition (Dr Claire Smith, Professor Rachael Taylor), and Paediatric Sleep Health (Associate Professor Barbara Galland).

* This study was funded by the Sir John Walsh Institute and by Cure Kids.

Publication details:

Relationship between chewing features and body mass index in young adolescents

Ghassan Idris, Claire Smith, Barbara Galland, Rachael Taylor, Christopher J. Robertson, Hamza Bennani, and Mauro Farella

Pediatric Obesity



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