title: A comparison of chewing rate between overweight and normal BMI individuals.
abstract: OBJECTIVE
  Previous attempts to identify an 'obese eating style' have led to conflicting findings. This observational study compared the chewing features of overweight or obese young adults with those of normal range BMI. We hypothesised that chewing features are individual-specific and differ between participants of a normal BMI and high BMI.
  
  
  METHODS
  Fourteen overweight to obese participants (BMI≥25.0) were pairwise matched with 14 normal range BMI participants (18.5<BMI<25.0). Masticatory muscle activity was recorded using portable recorders during consumption of two rice meals in a laboratory setting and one pizza meal in the natural environment. A previously validated algorithm was used to assess time-frequency features of chewing episodes, including rate, duration, and power. Masticatory performance was assessed by a sieve test and was expressed as the percentage of particles ≤2mm after a standardised chewing test.
  
  
  RESULTS
  Regardless of the meal, chewing rate was remarkably consistent among participants (ICC=0.89; 95% CI=0.79-0.94). Chewing rate did not differ between high and normal BMI participants (p>0.05), whereas chewing power was significantly higher in high BMI participants (p<0.05). No other differences in chewing characteristics were found between BMI groups. Participants chewed at similar rate in the natural environment (pizza) and in the laboratory (rice) setting (p>0.05). Masticatory performance did not differ significantly (p>0.05) between the high (55.9%) and normal (52.4%) BMI groups.
  
  
  CONCLUSIONS
  Within the limitations of the present study, chewing characteristics appear to be individual-specific with wide variability. Overweight participants chew at a similar rate to control participants, albeit slightly stronger. Our preliminary findings need to be replicated in larger samples.
authors: Department of Oral Sciences, University of Otago, New Zealand.
authors: Amy Kristin
authors: AK
authors: White
authors: Department of Human Nutrition, University of Otago, New Zealand.
authors: Bernard
authors: B
authors: Venn
authors: Centre for Child Health Research, Auckland University of Technology, New Zealand.
authors: Louise Weiwei
authors: LW
authors: Lu
authors: Centre for Child Health Research, Auckland University of Technology, New Zealand.
authors: Elaine
authors: E
authors: Rush
authors: Centre for Dental Medicine, University of Zurich, Switzerland.
authors: Luigi Maria
authors: LM
authors: Gallo
authors: Department of Human Nutrition, University of Otago, New Zealand.
authors: Janet Lee Ching
authors: JL
authors: Yong
authors: Department of Oral Sciences, University of Otago, New Zealand. Electronic address: mauro.farella@otago.ac.nz.
authors: Mauro
authors: M
authors: Farella
mesh_terms: D000293:Adolescent; D000328:Adult; D015992:Body Mass Index; D016000:Cluster Analysis; D004576:Electromyography; D005071:Evoked Potentials; D005260:Female; D005583:Fourier Analysis; D006801:Humans; D008297:Male; D008409:Mastication / Q000502:physiology*; D008410:Masticatory Muscles / Q000503:physiopathology; D050177:Overweight / Q000503:physiopathology*; D055815:Young Adult
keywords: Body mass index; Chewing rate; Electromyography; Mastication; Natural environment