Abstract Eating slowly is associated with a lower body mass index. However, the underlying mechanism is poorly understood. Here, our objective was to determine whether eating a meal at a slow rate ...improves episodic memory for the meal and promotes satiety. Participants ( N = 40) consumed a 400 ml portion of tomato soup at either a fast (1.97 ml/s) or a slow (0.50 ml/s) rate. Appetite ratings were elicited at baseline and at the end of the meal (satiation). Satiety was assessed using; i) an ad libitum biscuit ‘taste test’ (3 h after the meal) and ii) appetite ratings (collected 2 h after the meal and after the ad libitum snack). Finally, to evaluate episodic memory for the meal, participants self-served the volume of soup that they believed they had consumed earlier (portion size memory) and completed a rating of memory ‘vividness’. Participants who consumed the soup slowly reported a greater increase in fullness, both at the end of the meal and during the inter-meal interval. However, we found little effect of eating rate on subsequent ad libitum snack intake. Importantly, after 3 h, participants who ate the soup slowly remembered eating a larger portion. These findings show that eating slowly promotes self-reported satiation and satiety. For the first time, they also suggest that eating rate influences portion size memory. However, eating slowly did not affect ratings of memory vividness and we found little evidence for a relationship between episodic memory and satiety. Therefore, we are unable to conclude that episodic memory mediates effects of eating rate on satiety.
Laboratory studies have demonstrated that experimental manipulations of oral processing can have a marked effect on energy intake. Here, we explored whether variations in oral processing across a ...range of unmodified everyday meals could affect post-meal fullness and meal size. In Study 1, female participants (N = 12) attended the laboratory over 20 lunchtime sessions to consume a 400-kcal portion of a different commercially available pre-packaged meal. Prior to consumption, expected satiation was assessed. During each meal, oral processing was characterised using: (i) video-recordings of the mouth and (ii) real-time measures of plate weight. Hunger and fullness ratings were elicited pre- and post-consumption, and for a further three hours. Foods that were eaten slowly had higher expected satiation and delivered more satiation and satiety. Building on these findings, in Study 2 we selected two meals (identical energy density) from Study 1 that were equally liked but maximised differences in oral processing. On separate days, male and female participants (N = 24) consumed a 400-kcal portion of either the "fast" or "slow" meal followed by an ad libitum meal (either the same food or a dessert). When continuing with the same food, participants consumed less of the slow meal. Further, differences in food intake during the ad libitum meal were not compensated at a subsequent snacking opportunity an hour later. Together, these findings suggest that variations in oral processing across a range of unmodified everyday meals can affect fullness after consuming a fixed portion and can also impact meal size. Modifying food form to encourage increased oral processing (albeit to a lesser extent than in experimental manipulations) might represent a viable target for food manufacturers to help to nudge consumers to manage their weight.
Research has shown that people consume more food when offered larger portions, and that reducing exposure to large food portions and packages could decrease the average daily energy consumed. In this ...context, our aim is to develop strategies to promote healthier eating behaviors by reducing portion selection and intake. The present research investigates the impact of different visual attributes of foods on quantity perception and portion selection. In the first study, we tested whether modifying the shape of a familiar food influenced the ideal portion size in adults. In the second study, we assessed the impact of shape, number of units, size, and color variety on a perceived quantity for a familiar multiunit product in children. Participants (
= 70 adults,
= 62 children) completed different picture-based computer tasks. As hypothesized: (1) adults selected a smaller ideal portion size for an elongated product than for wider and thicker shapes, and (2) children's perception of food quantity was primarily driven by number of pieces, with smaller effects of size and elongation. Perceived quantity was not influenced by color variety. These findings suggest that it may be possible to reduce the size of food portions without negatively impacting perceived quantity, and to provide opportunities to nudge consumers towards smaller portions while maintaining satisfaction.
It is critical to develop ecologically valid experimental methods to assess consumers' food-related behaviors. Ad libitum approaches are often used but may not be appropriate for studies with ...children or with products that are not typically consumed until the individual feels full. The current study presents novel methods to assess children's size perception and portion preference for gummy candies. In the first study, 62 children (30 boys, 32 girls) aged 6 to 9 years completed two matching tasks: one using pictures on a computer screen, and a similar task where the products were physically manipulated. Results of the two matching tasks were correlated, demonstrating that a computer-based approach could be used to predict the factors influencing children's perception of food amount: the number, size, and shape of pieces. In the second study, a portioning measure was developed to investigate whether the factors identified in the matching tasks were confirmed in a task that more closely represented portion selection in the real world. The effects observed in the matching tasks could not be replicated in the portioning task. The size of each item had no significant impact on the portion selection, suggesting that it may be possible to reduce the size of pieces in snacks where multiple pieces are typically consumed without negatively impacting perceived quantity in children, thus offering a promising strategy to nudge children toward choosing smaller portions.
Deliberately eating at a slower pace promotes satiation and eating quickly has been associated with a higher body mass index. Therefore, understanding factors that affect eating rate should be given ...high priority. Eating rate is affected by the physical/textural properties of a food, by motivational state, and by portion size and palatability. This study explored the prospect that eating rate is also influenced by a hitherto unexplored cognitive process that uses ongoing perceptual estimates of the volume of food remaining in a container to adjust intake during a meal. A 2 (amount seen; 300 ml or 500 ml) x 2 (amount eaten; 300 ml or 500 ml) between-subjects design was employed (10 participants in each condition). In two 'congruent' conditions, the same amount was seen at the outset and then subsequently consumed (300 ml or 500 ml). To dissociate visual feedback of portion size and actual amount consumed, food was covertly added or removed from a bowl using a peristaltic pump. This created two additional 'incongruent' conditions, in which 300 ml was seen but 500 ml was eaten or vice versa. We repeated these conditions using a savoury soup and a sweet dessert. Eating rate (ml per second) was assessed during lunch. After lunch we assessed fullness over a 60-minute period. In the congruent conditions, eating rate was unaffected by the actual volume of food that was consumed (300 ml or 500 ml). By contrast, we observed a marked difference across the incongruent conditions. Specifically, participants who saw 300 ml but actually consumed 500 ml ate at a faster rate than participants who saw 500 ml but actually consumed 300 ml. Participants were unaware that their portion size had been manipulated. Nevertheless, when it disappeared faster or slower than anticipated they adjusted their rate of eating accordingly. This suggests that the control of eating rate involves visual feedback and is not a simple reflexive response to orosensory stimulation.
Natural genetic variation can have a pronounced influence on human taste perception, which in turn may influence food preference and dietary choice. Genome-wide association studies represent a ...powerful tool to understand this influence. To help optimize the design of future genome-wide-association studies on human taste perception we have used the well-known TAS2R38-PROP association as a tool to determine the relative power and efficiency of different phenotyping and data-analysis strategies. The results show that the choice of both data collection and data processing schemes can have a very substantial impact on the power to detect genotypic variation that affects chemosensory perception. Based on these results we provide practical guidelines for the design of future GWAS studies on chemosensory phenotypes. Moreover, in addition to the TAS2R38 gene past studies have implicated a number of other genetic loci to affect taste sensitivity to PROP and the related bitter compound PTC. None of these other locations showed genome-wide significant associations in our study. To facilitate further, target-gene driven, studies on PROP taste perception we provide the genome-wide list of p-values for all SNPs genotyped in the current study.
Lipid content in food strongly influences food perception on the level of textural properties. Lipids in contact with the tongue and palate are substantially responsible for the sensory impact of a ...product. The aim of this study is to investigate the impact of oil content on the thickness of lipid deposition on oral surface as well as on the mouthfeel perception. The fluorescent probe method was used to study the thickness of lipid deposition on oral surface. We observed an increase in the thickness of lipid deposition depending on the increase of oil content in oil/water dispersions. Clear correlation was shown between the thickness of lipid deposition on oral surfaces and the perception of mouthfeel. A direct measure of undisrupted deposition of food components on oral surface contributes to the understanding of the behaviour of food components in the mouth and their influence on mouthfeel perception.
The oral perception of fat has traditionally been considered to rely mainly on texture and olfaction, but recent findings suggest that taste may also play a role in the detection of long chain fatty ...acids. The two G-protein coupled receptors GPR40 (Ffar1) and GPR120 are activated by medium and long chain fatty acids. Here we show that GPR120 and GPR40 are expressed in the taste buds, mainly in type II and type I cells, respectively. Compared with wild-type mice, male and female GPR120 knock-out and GPR40 knock-out mice show a diminished preference for linoleic acid and oleic acid, and diminished taste nerve responses to several fatty acids. These results show that GPR40 and GPR120 mediate the taste of fatty acids.
The role of fat content and type of surfactant for oral friction processes and texture perception of oil-in-water emulsions was assessed. Emulsions at 22% and 33% fat content containing either sodium ...caseinate or a sucrose ester as emulsifier were compared with viscosity-adapted aqueous solutions of dextran using both sensory evaluation and friction coefficient measurements on a tongue-palate contact model. The impact of saliva on the emulsion droplet size distribution was studied using tribology, differential interference contrast microscopy and light diffraction measurements. Emulsions at 33% and the corresponding iso-viscous aqueous solutions were discriminated in the sensory experiment whereas emulsions at 22% were not. Friction was significantly different for emulsions at 33% and the corresponding iso-viscous aqueous solutions. The difference was not significant for emulsions with 22% fat level when compared with the iso-viscous aqueous solutions. Saliva significantly decreased the friction coefficient of emulsions depending on the surfactant and amount of fat used.
Temporal release and retention of aroma compounds from structured emulsions (where unsaturated monoglycerides are added to the oil) and conventional oil-in-water emulsions were studied using in vitro ...dynamic headspace analysis by proton-transfer reaction mass spectrometry and static headspace analysis by gas chromatography–mass spectrometry. Under dynamic conditions, the structured emulsion exhibited delayed release compared to the oil-in-water emulsion containing the same lipid content of 5%. The time to maximum concentration T max of amphiphilic and lipophilic aroma compounds increased by a factor of 1.2 (for 3E-hexenal) to 1.9 (for octanal). The aroma release profile of the 5% lipid structured emulsion was close to that obtained for the oil-in-water emulsion containing 10% lipid. Under static conditions, the 5% lipid structured emulsion retained more of the most lipophilic aroma compounds than its counterpart 5% oil-in-water nonstructured emulsion. The present study provides potential solutions for modulating aroma release profiles of reduced-fat foods by self-assembly structures.
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