Influence of oral processing on appetite and food intake – A systematic review and meta-analysis

Abstract

Food delivers energy, nutrients and a pleasurable experience. Slow eating and prolonged oro-sensory exposure to food during consumption can enhance the processes that promote satiation. This systematic review and meta-analysis investigated the effects of oral processing on subjective measures of appetite (hunger, desire to eat) and objectively measured food intake. The aim was to investigate the influence of oral processing characteristics, specifically "chewing" and "lubrication", on "appetite" and "food intake". A literature search of six databases (Cochrane library, PubMed, Medline, Food Science and Technology Abstracts, Web of Science, Scopus), yielded 12161 articles which were reduced to a set of 40 articles using pre-specified inclusion and exclusion criteria. A further two articles were excluded from the meta-analysis due to missing relevant data. From the remaining 38 papers, detailing 40 unique studies with 70 subgroups, raw data were extracted for meta-analysis (food intake n = 65, hunger n = 22 and desire to eat ratings n = 15) and analyzed using random effects modelling. Oral processing parameters, such as number of chews, eating rate and texture manipulation, appeared to influence food intake markedly but appetite ratings to a lesser extent. Meta-analysis confirmed a significant effect of the direct and indirect aspects of oral processing that were related to chewing on both self-reported hunger (-0.20 effect size, 95% confidence interval CI: -0.30, -0.11), and food intake (-0.28 effect size, 95% CI: -0.36, -0.19). Although lubrication is an important aspect of oral processing, few studies on its effects on appetite have been conducted. Future experiments using standardized approaches should provide a clearer understanding of the role of oral processing, including both chewing and lubrication, in promoting satiety.

Oral Lubrication Matters: Effects on Satiety

“…It was hypothesized that more chewing would lead to lower food intake, as reported in previous studies. 3 Interestingly, results found that snack intake was only lowered after the consumption of the soft/high lubricating preload sample (1.5κC0.5NaA) compared to the hard/low lubricating preload (3κC), but not after the control, suggesting that not the chewing but the lubricating properties governed subsequent intake of a salty snack. Sensory ratings for the different preloads did not reveal a significant difference in terms of pleasantness, strength of mint flavour or sweetness, and therefore these characteristics could not account for the suppressed food intake after the soft/high lubricating preload (1.5κC0.5NaA).…”

“…This is inconsistent with previous research, which showed that higher level of chewing did indeed reduce food intake. 3,14,18 This might be explained by the short exposure time of 10 minutes and the low amount of elicited chewing in this period, indicating that the total chewing time may not have been sufficiently long enough to influence food intake. Future research incorporating more hydrogel pieces into the preload to increase overall chewing time may find a more pronounced effect on food intake.…”

“…13 Although the role of oral processing on satiation and satiety has been well established, the quantitative understanding of which dimensions of oral processing influence this has remained elusive. 3,[14][15][16][17][18] Based on a recent systematic review and metaanalysis on relating oral processing to satiety, it was demonstrated that extending the orosensory exposure time to foods leads to a significant reduction in self-reported hunger (-0.20 effect size, 95% confidence interval CI: -0.30, -0.11) and food intake (-0.28 effect size, 95% CI: -0.36, -0.19). 3 Interestingly, in many if not most of these satiety trials involving oro-sensory cues, 'food rheology' (i.e.…”

“…3,[14][15][16][17][18] Based on a recent systematic review and metaanalysis on relating oral processing to satiety, it was demonstrated that extending the orosensory exposure time to foods leads to a significant reduction in self-reported hunger (-0.20 effect size, 95% confidence interval CI: -0.30, -0.11) and food intake (-0.28 effect size, 95% CI: -0.36, -0.19). 3 Interestingly, in many if not most of these satiety trials involving oro-sensory cues, 'food rheology' (i.e. liquid versus solid foods, texture/thickness manipulations) has been used as a 'gold standard'-design tool to influence the number of chews, oral residence time or eating rate, and thus, impact satiety outputs such as appetite ratings (hunger desire to eat), food intake and gut hormonal release.…”

“…22,23 Although oral lubrication or friction provided by food is a crucial aspect of this fundamental biological process occurring in the mouth, its' mechanistic effects on psychological and physiological consequences implicated in altering the motivation to eat remain under-researched. 3 …”