title: Effects of chewing on appetite, food intake and gut hormones: A systematic review and meta-analysis.
abstract: OBJECTIVE
  To seek insights into the relationship between chewing, appetite, food intake and gut hormones, and to consider potentially useful recommendations to promote benefits of chewing for weight management.
  
  
  METHODS
  Papers were obtained from two electronic databases (Medline and Cochrane), from searches of reference lists, and from raw data collected from the figures in the articles. A total of 15 papers were identified that detailed 17 trials. All 15 papers were included in the systematic review; however, a further five studies were excluded from the meta-analysis because appropriate information on hunger ratings was not available. The meta-analysis was conducted on a total of 10 papers that detailed 13 trials.
  
  
  RESULTS
  Five of 16 experiments found a significant effect of chewing on satiation or satiety using self-report measures (visual analogue scales, VASs). Ten of 16 experiments found that chewing reduced food intake. Three of five studies showed that increasing the number of chews per bite increased relevant gut hormones and two linked this to subjective satiety. The meta-analysis found evidence of both publication bias and between study heterogeneity (IA(2) = 93.4%, tau(2) = 6.52, p < 0.001) which decreased, but remained, when covariates were considered. Analysis of the heterogeneity found a substantial effect of the fasting period where the duration of fasting influenced the decrease in hunger due to chewing. Prolonged mastication significantly reduces self-reported hunger levels (hunger: − 2.31 VAS point, 95% CI [− 4.67, − 1.38], p < 0.001).
  
  
  CONCLUSIONS
  Evidence currently suggests that chewing may decrease self-reported hunger and food intake, possibly through alterations in gut hormone responses related to satiety. Although preliminary, the results identify a need for additional research in the area. Focused, uniform, experimental designs are required to clearly understand the relationships that exist between mastication, appetite, satiety, food intake and, ultimately, body weight.
authors.affiliation: Wrigley (Mars Inc.), 1132 West Blackhawk Street, Chicago, IL 60642, USA. Electronic address: Sophie.Kergoat@Wrigley.com.
authors.forename: Sophie
authors.initials: S
authors.lastname: Miquel-Kergoat
authors.affiliation: VAB Nutrition, 1 Rue Claude Danziger, 63100 Clermont-Ferrand, France.
authors.forename: Veronique
authors.initials: V
authors.lastname: Azais-Braesco
authors.affiliation: Nutrition Department, University of California, Davis, 3135 Meyer Hall, One Shields Avenue, Davis, CA 95616-5270, USA.
authors.forename: Britt
authors.initials: B
authors.lastname: Burton-Freeman
authors.affiliation: School of Psychology, University of Leeds, Leeds LS2 9JT, United Kingdom.
authors.forename: Marion M
authors.initials: MM
authors.lastname: Hetherington
mesh_terms: D001066:Appetite / Q000502:physiology*; D004435:Eating / Q000502:physiology* / Q000523:psychology; D005768:Gastrointestinal Hormones / Q000378:metabolism*; D006801:Humans; D006815:Hunger / Q000502:physiology; D008409:Mastication / Q000502:physiology*; D012527:Satiation / Q000502:physiology
chemical_list: D005768:Gastrointestinal Hormones
keywords: Appetite; Chewing; Food intake; Gut hormones; Hunger; Meta-analysis