Article

Unit Bias A New Heuristic That Helps Explain the Effect of Portion Size on Food Intake

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Abstract

People seem to think that a unit of some entity (with certain constraints) is the appropriate and optimal amount. We refer to this heuristic as unit bias. We illustrate unit bias by demonstrating large effects of unit segmentation, a form of portion control, on food intake. Thus, people choose, and presumably eat, much greater weights of Tootsie Rolls and pretzels when offered a large as opposed to a small unit size (and given the option of taking as many units as they choose at no monetary cost). Additionally, they consume substantially more M&M's when the candies are offered with a large as opposed to a small spoon (again with no limits as to the number of spoonfuls to be taken). We propose that unit bias explains why small portion sizes are effective in controlling consumption; in some cases, people served small portions would simply eat additional portions if it were not for unit bias. We argue that unit bias is a general feature in human choice and discuss possible origins of this bias, including consumption norms.

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... The implication is that individuals who are less sensitive to stimulus reduction are more sensitive to stimulus increment, and vice versa. While these findings are new in terms of chemosensory capacity, such asymmetrical sensitivities to high-versus low-stimulus intensities are in line with findings from comparable auditory (Geier, Rozin, & Doros, 2006;Kerameas et al., 2015;Rinne et al., 2006) and visual (Blundell & Gillett, 2001;Robinson et al., 2016) analyses. ...
... Such asymmetry in sensory sensitivity might potentially play an important role in influencing individual dietary choices and intake. While these findings seem highly novel in terms of chemosensory capacity, previous studies based on visual estimation of portion sizes have also given some interesting and relevant insights (Geier et al., 2006;Kerameas et al., 2015). Specifically, in a recent study, participants were presented with a series of images of 'below-normal', 'normal', and 'above-normal' portion sizes of selected food items and asked to judge relative portion size changes. ...
... No significant difference in EI(Sweet) was observed for the individuals with low-BMI p=0. 200). ...
Thesis
Obesity has become a critical health issue in many developed countries, including New Zealand. While the aetiology of obesity is likely to be multifactorial, overconsumption is deemed as a key behavioural contributor to the growing obesity rate. Emerging sensory nutritional research has proposed that obesity is linked to altered olfactory and gustatory sensitivities, which can in turn influence consumption, particularly of foods rich in sugar, salt, and fats. Despite being promising, empirical studies to test for this hypothesis have returned highly controversial results. The present doctoral thesis aims to ‘systematically evaluate the role of olfaction and gustation in regulating an individual’s adiposity and eating behaviour’, using well-validated psychophysical, nutritional, and food-psychological approach. The present thesis firstly aimed to develop and test for new approaches to quantify individual chemosensory sensitivities to food-related stimuli, based on assessments of individual performance to decremental (d′(d)) and incremental (d′(i)) stimulus range. Subsequently, these sensitivity measures were analysed against inter-individual differences in adiposity measures and eating behaviour. Additional exploratory research was performed to further analyse possible factors driving chemosensory links to food-related behaviour. Two separate datasets were collected in this thesis, with Data Collection 1 involving N=70 (age range = 21-39 years, BMI range = 20.5-48.1 kg·m-2) and Data Collection 2 involving N=61 (age range = 21-39 years, BMI range = 19.7-41.5 kg·m-2) participants. The results from the first analysis show that individuals’ sensitivities to decremental stimulus range (d′(d)) and to incremental stimulus range (d′(i)) represent distinct measures. Furthermore, the measure of d′(d) is positively associated with adiposity measures, whereas d′(i) exhibits a negative relationship. Furthermore, these two separate sensitivity measures had significant, but contradictory, relationships with snack intake and total habitual energy intake. Specifically, individuals with poor olfactory and gustatory sensitivities (high d′(d) and low d′(i)) appeared to consume more sweet versus savoury snacks, than their counterparts, pointing to an important differentiating role of snack consumption. In the context of the aforementioned findings, the last study of the thesis tested whether exposure to olfactory and gustatory cues in a meal influences subsequent snack choice and intake. With a repeated-subject design over one control and four testing sessions, the participants had breakfasts with manipulated olfactory and gustatory characteristics and recorded their snack intake throughout the day. Results from this study revealed that high-intensity olfactory and gustatory characteristics of a meal reduce sweet snack intake and increase the non-sweet snack intake, while total snack intake is maintained across the sessions. Specifically, individuals with high gustatory sensitivity showed more sensory-specific effects compared to the low-sensitivity group. Moreover, the high-BMI group showed sensory-specific effects for low- and high-intensity sweet taste cues, in contrast, the low-BMI group showed sensory-specific effects only for the high-intensity taste cues. Overall, the findings of this specific study highlight that the olfactory and gustatory cues of a meal may have a day-long effect on snack choice, providing novel insights into the observed association between sensory sensitivity and adiposity. Overall, this doctoral thesis systematically assessed the role of individual olfactory and gustatory sensitivities in influencing adiposity and eating behaviour. With multifactorial data ranging across sensory science, nutrition and food psychology, this thesis provides new insights into inter and intra-individual differences in olfactory and gustatory sensitivities, and their important links to eating behaviour.
... In times when obesity takes on almost epidemic proportions, researchers are increasingly looking at how manipulating the presentation and size of food servings can nudge people into healthier eating habits. Guided by this, scholars have discovered that eating behavior/decisions can be influenced by the "unit bias" (Geier et al., 2006)-the tendency for people to perceive any given unit of food as the default, regardless of its actual volume or physical attributes and thus as the appropriate amount to eat-or by its extension, the "portion size effect" (Rolls et al., 2006)-the tendency for people to perceive any portion size as the default and thus to consume more of an objectively larger than smaller portion. Indeed, Geier et al. (2006) define the unit bias (presumably underlying the portion size effect) as the tendency to "think that a unit of some entity (with certain constraints) is the appropriate and optimal amount" (p. ...
... Guided by this, scholars have discovered that eating behavior/decisions can be influenced by the "unit bias" (Geier et al., 2006)-the tendency for people to perceive any given unit of food as the default, regardless of its actual volume or physical attributes and thus as the appropriate amount to eat-or by its extension, the "portion size effect" (Rolls et al., 2006)-the tendency for people to perceive any portion size as the default and thus to consume more of an objectively larger than smaller portion. Indeed, Geier et al. (2006) define the unit bias (presumably underlying the portion size effect) as the tendency to "think that a unit of some entity (with certain constraints) is the appropriate and optimal amount" (p. 521). ...
... 521). In their studies, participants tended to choose and wanted to consume a greater amount of Tootsie Rolls and pretzels when these were offered in a large as opposed to a smaller sized unit (Geier et al., 2006). Importantly, the common methodological paradigm used in studies on the unit bias and portion size effect is to manipulate units/portions by creating objective volume, weight, or size differences between food units/portions, showing that a higher volume, weight or size induces increased food desire and/or consumption [see also : Zlatevska et al. (2014), Kerameas et al. (2015), Vandenbroele et al. (2019)]. ...
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Article
In the present work we extend research into the unit bias effect and its extension—the portion size effect—by demonstrating the existence of a “Gestalt bias.” Drawing on the tenets of Gestalt psychology, we show that a unit bias effect can be observed for food portions that are composed of identical basic units, but which are subjectively grouped into, or perceived as a Gestalt—a larger whole. In three studies, we find that such subjectively constructed food wholes constitute a new (perceptual) unit that is perceived bigger than the units it is constructed from, thereby prompting increased eating and desire to eat.
... From October 2018 to February 2019, healthy adults were recruited from the greater Lafayette, Indiana, area through flyers and word-ofmouth to participate in the study. Eligibility was determined through the following inclusion criteria: 1) age range of 18-55 y; 2) normal to obese [BMI (kg/m 2 ): [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32]; 3) healthy, nondiabetic; 4) not currently or previously following a weight-loss or other special diet (in the past 6 mo); 5) nonsmoking (for the past 6 mo); 6) not been clinically diagnosed with an eating disorder; and 7) habitually snacks (i.e., at least 4 times/wk) between lunch and dinner. ...
... One is the idea of unit bias. Geier et al. (26) defined unit bias as "a sense that a single entity (within a reasonable range of sizes) is the appropriate amount to engage, consume, or consider." For example, if an individual is consuming a bag of potato chips, they may assume that 1 chip bag (regardless of how large, but also within reason) is the appropriate amount of chips for them to consume. ...
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Background While energy and nutritional content of snacks can contribute to overconsumption, other factors within the modern food environment may also influence the amount and types of snacks consumed. Objectives To examine whether snack package size and variety influence free-living snacking behavior in healthy adults. The impact of intuitive eating score on snacking behavior was also examined. Methods Thirty adults (age: 23.6±0.8y; BMI: 22.8±0.5 kg/m2) participated in a randomized crossover-design study (Clinicaltrials.gov NCT03940105). Participants were provided, in randomized order, with the following isocaloric snack exposures to consume for 3-d/exposure: 1) CONTROL: highly appealing/appetizing snacks (e.g., dessert snacks, candy, savory snacks, fruits and vegetables, protein snacks); 2) LARGE-PACKAGE: similar snacks as CONTROL but in larger package sizes; and 3) VARIETY: larger variety of snacks. The primary outcomes included the 3-day average ad libitum snack energy, macronutrient content, and food choices for each snack exposure. The secondary outcome was the intuitive eating score and snacking behavior. Results LARGE-PACKAGE increased snack intake by 11.9% (1150±81kcal) vs. CONTROL (1030±71kcal, P = 0.04), whereas VARIETY snack intake (1030±69kcal) was no different compared to CONTROL (P = 1.0). LARGE-PACKAGE increased consumption of desserts vs. CONTROL (P = 0.03) and VARIETY (P = 0.02). Alternately, VARIETY increased consumption of fruits and vegetables vs. LARGE-PACKAGE (P = 0.01) and CONTROL (P = 0.01). Intuitive eating score was not significantly associated with snack intake or snack choice (all, P>0.05). Conclusions: Snack package size and variety differentially influence energy intake and food choices in healthy adults.
... Research has also shown how changing the component size of food is relevant, e.g. full-size brownies compared to halved (67) , whole pretzels also halved (68) . Such effects have been attributed to a unit bias (68) , a heuristic that choosing one item is appropriate. ...
... full-size brownies compared to halved (67) , whole pretzels also halved (68) . Such effects have been attributed to a unit bias (68) , a heuristic that choosing one item is appropriate. Presenting food in fun formats has also been investigated; one study conducted in primary schools found that consumption almost doubled when whole wheat bread was presented in fun shapes (69) . ...
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Article
Populations' diets typically fall short of recommendations. The implication of this on ill health and quality of life is well established, as are the subsequent health care costs. An area of growing interest within public health nutrition is food choice architecture; how a food choice is framed and its influence on subsequent food selection. In particular, there is an appeal to manipulating the choice architecture in order to nudge individuals' food choice. This review outlines the current understanding of food choice architecture, theoretical background to nudging and the evidence on the effectiveness of nudge strategies, as well as their design and implementation. Interventions emphasising the role of nudge strategies have investigated changes to the accessibility, availability and presentation of food and the use of prompts. Empirical studies have been conducted in laboratories, online and in real-world food settings, and with different populations. Evidence on the effectiveness of nudge strategies in shifting food choice is encouraging. Underpinning mechanisms, not yet fully explicated, are proposed to relate to salience, social norms and the principle of least effort. Emerging evidence points to areas for development including the effectiveness of choice architecture interventions with different and diverse populations, and the combined effect of multiple nudges. This, alongside further examination of theoretical mechanisms and guidance to engage and inspire across the breadth of food provision, is critical. In this way, the potential of choice architecture to effect meaningful change in populations' diets will be realised.
... The least effective nudges were cognitive-oriented interventions (such as descriptive nutritional labeling, evaluative nutritional labeling, and visibility enhancements). Behavior-oriented nudges such as making unhealthy foods less convenient to consume, using less convenient serving utensils (tongs versus spoons), or offering smaller-sized utensils, have been shown to reduce the amount consumed [26,27]. ...
... The special spoon cues customers to visually see and achieve the recommended amount. Our findings align with previous studies showing that behavior-oriented nudges are most effective in changing consumption behavior, such as making unhealthy foods less convenient to consume by using less convenient serving utensils (tongs versus spoons) or offering smaller-sized utensils [22,26,27]. ...
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Article
High sodium consumption is one of the four major risk factors contributing to non-communicable diseases around the world. Thailand has one of the highest rates of sodium consumption, with fish sauce being one of the main sources. The aim of this study was to examine whether changes in the micro-environment factors can affect fish sauce consumption behavior in a university setting in Thailand. We implemented four interventions (with one control) in five canteens across a Thai university. The study design was a Latin square, where the five canteens were randomized over five weeks to implement four interventions plus a control. Our interventions included behavior-oriented, cognitive-oriented, and affective-oriented nudges aimed to reduce the amount of fish sauce people add to their noodles during lunchtime at the university canteens. Results indicate that a simple change in how fish sauce was served can reduce fish sauce consumption. Serving fish sauce in a bowl with a spoon reduced the amount of fish sauce used per noodle bowl by 0.25 grams, compared to the normal condition where fish sauce is served in a bottle. Using a specially-designed spoon with a hole induced a larger reduction of 0.58 grams of fish sauce used per bowl. The other two interventions, cognitive- and affective- oriented nudges, also showed reductions of fish sauce usage, but the differences were not statistically significant. The findings can be used for policy implementation to advocate the use of a smaller sized spoon and a bowl to serve fish sauce instead of a bottle to reduce sodium consumption among Thai people.
... Instead, a compelling explanation of the appropriateness account is the unit bias heuristic, which holds that people view the given portion as a unit rather than a certain amount of grams or millilitres (Geier, Rozin, & Doros, 2006). The authors introduced and tested the proposition that people tend to view one unit of food (i.e., a piece of candy or slice of cake) as an appropriate amount. ...
... We relied on the unit bias heuristic as a valuable account to explain this particular portion size effect. While this account states that people view portions (i.e., teaspoons) as whole units or entities (Geier et al., 2006), we found no clear support for this in the results of this study. The participants might not have viewed 2 teaspoons as two units but rather as an intuitive estimate of the quantity needed to arrive at the desired level of sweetness. ...
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Article
Seemingly insignificant daily practices, such as sugar usage in tea, can have a great accumulated impact on societal issues, such as obesity. That is why these behaviours are often the target of nudge interventions. However, when these behaviours are performed frequently they may turn into habits that are difficult to change. The aim of the current study was to investigate whether a portion size nudge has the potential to work in accordance with (instead of against) existing habits. Specifically, it was tested whether a portion size nudge would be more effective in reducing the amount of sugar added to tea, when people have a strong habit of adding a fixed amount of teaspoons of sugar to a cup of tea. The study (N = 123) had a mixed factorial design with teaspoon size (reduced size vs. control) as a within-subject factor, and habit disruption context condition (hot tea vs. cold tea) as a between-subjects factor. A paired t-test indicated that this nudge reduced sugar intake on average by 27% within subjects. When the context allowed for automatic enactment of the habit, the effectiveness of this nudge was moderated by habit strength. Surprisingly, the nudge effect was actually less pronounced when people had a strong habit. Implications for effective nudge interventions are discussed.
... Smaller bottles have the potential to decrease consumption by increasing the effort required to open and consume more than one bottle [12], or as a result of a tendency for people to consume a specific number of bottles in any one drinking occasion, regardless of bottle size [21]. Smaller bottles could also increase consumption by reducing barriers to consumption that are present for larger sizes [22], including any inhibitions over opening larger packages, perhaps increasing the frequency of drinking episodes. ...
... There are several possible mechanisms for this 'portion size effect', including social and personal norms regarding how to eat or drink [25,30]. Smaller bottles might decrease consumption by signalling a completed episode of consumption when empty, reflecting a tendency for people to consume in 'units' regardless of portion or package size [21]. It may also have an effect by making additional intake of wine effortful [12]. ...
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Article
Aim To assess the impact of purchasing wine in 50 cl bottles compared with 75 cl bottles on the amount of wine consumed at home. Design Cross‐over randomized controlled trial with a ‘usual behaviour’ period of a maximum of 3 weeks between conditions. Setting Households in the United Kingdom. Participants One hundred and eighty‐six households that consumed between two and eight 75 cl bottles of wine each week. Intervention Households were randomized to the order in which they purchased wine in two bottle sizes. During two 14‐day intervention periods, households purchased a pre‐set volume of wine—based on their baseline self‐reported weekly consumption—in either 75 cl bottles or 50 cl bottles. On days 7 and 14 of each study period, participating households sent photographs of each purchased wine bottle. Measurements The primary outcome was the volume of study wine in millilitres (ml) consumed during each study period estimated through returned photographs. The secondary outcome was the rate of consumption measured by the mean number of days taken to drink 1.5 litres from each bottle size. Findings One hundred and sixty‐six of 186 enrolled households satisfactorily completed the study. After accounting for pre‐specified covariates, 191.1 ml [95% confidence interval (CI) = 42.03–339.2] or 4.5% (95% CI = 1.0–7.9%) more wine was consumed per 14‐day period from 75‐cl bottles than from 50‐cl bottles. Consumption was 5.8% faster (95% CI = –10.9 to –0.4%) from 75 cl bottles than from 50 cl bottles. Conclusions Consuming wine at home from 50 cl bottles, compared with 75 cl bottles, may reduce both amount consumed and rate of consumption.
... According to the standard way of consuming foods, it is accepted that a unit of food is an appropriate quantity, assuming that a unit is of minimum size. This explains why PSE is called unit bias, which motivates consumers to eat regardless of the size of the unit that is served (Geier et al. 2006). Visible signals related to the food portion affect the consumer's intake. ...
... Despite the portion size, consumers relate a single distribution as an adequate amount to eat, thus demonstrating the 'unit bias' mechanism (Geier et al. 2006). While multiple smaller units are related to insufficient food (Benton 2015), resulting in higher food consumption. ...
Chapter
Childhood appetite includes an understanding of satiety levels and their ability to respond to see, smell or taste food. Children who consume more junk food are at risk of being obese in adulthood through hunger hormones such as leptin and ghrelin, which can affect body mass index (BMI). The eating attitude depends on the feeding pattern of the parents to their children. Employed parents have difficulty giving attention to the proper diet of their children, which can lead to health disorders such as obesity, intellectual disability and stunted growth. The prevalence of obesity is increasing worldwide, which leads to a shortage of sleep, overeating and weight gain among children and adults. Sleep is an important modulator of neuro, endocrine and glucose metabolism in children. Due to the reduction of sleep, there is a dramatic increase in obesity with the decrease in glucose tolerance, the high sympathovagal balance, the increase in cortisol concentration at night, the reduction of leptin, the elevation of ghrelin. It is important that parents incorporate positive eating habits, a healthy diet, which has the potential to keep the child’s appetite in a normal range and avoid unnecessary childhood obesity and other eating disorders, thus creating a change in society.
... In theory, smaller bottles have the potential to both decrease and increase consumption. They may decrease consumption through one of several mechanisms: making additional intake of wine more effortful, through the need to acquire and open multiple bottles [10], or as a result of individuals' tendency to consume a specific number of bottles in any one episode of consumption regardless of bottle size, referred to as the "unit bias heuristic" [20]. Smaller bottles could also increase consumption through one of several mechanisms. ...
... Smaller bottles might decrease consumption by making additional intake of wine more effortful, [10] or as a result of individuals' tendency to consume a specific number of bottles in any one episode of consumption regardless of bottle size [20]. They might, however, also increase consumption by reducing barriers to consumption that are present for larger sizes [21] or as a result of being considered too small. ...
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Article
Background: Reducing alcohol consumption across populations would prevent many non-communicable diseases. Large packages increase food and non-alcoholic drink consumption and large glasses increase wine consumption. Smaller bottles may reduce alcohol consumption but their impact is uncertain. This study aims to (i) explore the feasibility and acceptability of conducting a large-scale randomised study to assess the impact of bottle size on in-home wine consumption and (ii) estimate the effect size and variance of the intervention on consumption to inform the design of future studies. Methods: Cross-over randomised study in which 16 households in Cambridge, England, consuming at least two 750-ml bottles of wine each week, received a pre-set volume of wine biweekly for 4 weeks, in 750-ml and 375-ml bottles, in random order. Consumption was assessed by recording the number of empty and partially full bottles at the end of each biweekly period. At the end of the study, household representatives were interviewed about their experiences of participating in the study. Results: The study procedures proved feasible. Comparable to similar trials, 14% of identified eligible households (18/125) consented to participate in the study. Attrition between consent and study completion was 11% (2/18) and 0% between study periods and 13% of households (2/16) correctly identified the study aim. The study procedures were considered acceptable. After adjusting for guest and out-of-home consumption, the difference in consumption between the 750-ml (3385.2 ml; SD = 1698.5) and 375-ml bottles (3376.7 ml; SD = 1719.0) was 8.4 ml (SD = 1235.4; 95%CI - 596.9, 613.8). Results suggest a possible order effect, with households receiving the 375-ml bottles first consuming more wine out of the 750-ml bottles and vice versa. This might also reflect an increase in consumption with study duration. Households receiving the 375-ml bottles first (6315.9 ml; SD = 3293.5) also drank less wine overall than those receiving the 750-ml bottles first (7335.4 ml; SD = 3735.4). Discussion: The findings support the feasibility and acceptability of running a large-scale randomised study to assess the impact of bottle size on in-home wine consumption. Due to the heterogeneous patterning of results, a future study will be powered using the variance observed in the current study to detect a meaningful reduction of 250 ml of wine when consumed from smaller compared with larger bottles. Trial registration: Open Science Framework (OSF): rmk43; May 23, 2017.
... Studies have shown that individuals consume smaller amounts when food is divided into several smaller units rather than fewer larger units [41]. Geier et al. [42] described these phenomena as 'unit bias' . Other factors may also drive the amount of food consumed including cost, availability and convenience of the food unit size [42]. ...
... Geier et al. [42] described these phenomena as 'unit bias' . Other factors may also drive the amount of food consumed including cost, availability and convenience of the food unit size [42]. ...
... First, smaller packs might reduce consumption by making it more effortful to smoke more-that is, to buy or open a new pack [10]. Secondly, it might reflect the tendency to consume a specific number of units in a pre-specified period of time [32]. This might be one glass or bottle of wine with dinner, and one pack of cigarettes in a day or during a 2-day period. ...
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Background and aims: Smoking fewer cigarettes per day may increase the chances of stopping smoking. Capping the number of cigarettes per pack is a promising policy option, but the causal impact of such a change is unknown. This study aimed to test the hypothesis that lowering cigarette pack sizes from 25 to 20 reduces the number of cigarettes smoked. Design: This randomized controlled cross-over trial had two 14-day intervention periods with an intervening 7-day period of usual behaviour. Participants purchased their own cigarettes. They were instructed to smoke their usual brand from either one of two sizes of pack in each of two 14-day intervention periods: (a) 25 cigarettes and (b) 20 cigarettes. Participants were randomized to the order in which they smoked from the two pack sizes (a-b; b-a). Setting: Canada. Participants: Participants were adult smokers who smoked from pack sizes of 25, recruited between July 2020 and June 2021. Of 252 randomized, 240 (95%) completed the study and 236 (94%) provided sufficient data for the primary analysis. Measurements: Cigarettes smoked per participant per day. Findings: Participants smoked fewer cigarettes per day from packs of 20 cigarettes [n = 234, mean = 15.7 standard deviation (SD) = 7.1] than from packs of 25 (n = 235, mean = 16.9, SD = 7.1). After adjusting for pre-specified covariates (baseline consumption and heaviness of smoking), modelling estimated that participants smoked 1.3 fewer cigarettes per day [95% confidence interval (CI) = -1.7 to -0.9], equivalent to 7.6% fewer (95% CI = -10.1 to -5.2%) from packs of 20 cigarettes. Conclusions: Smoking from packs of 20 compared with 25 cigarettes reduced the number of cigarettes smoked per day.
... People tend to consume in units of one, regardless of the size of a serving or container: one cup of coffee, one slice of cake, one bottle of wine, one glass of wine and so on [51]. Smaller units may therefore reduce consumption. ...
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This review summarises the evidence on the impact of serving and container size on how much people drink, interventions that have the potential to reduce alcohol consumption across populations, thereby improving health. A rapid search identified 10 published reports of 15 studies and 1 review. Four studies focused on serving size, eight studies and the review on glass size, two studies on bottle size and one on both glass and bottle size. Twelve studies and the review focused on wine, one study on beer and two on both. All were conducted in England, by just two research groups. Removing the largest serving size of wine decreased wine sales by 7.6% (95% CI −12.3%, −2.9%) in a study in 21 licenced premises, reflecting findings from two prior studies in semi-naturalistic settings. Adding a serving size for beer that was a size smaller than the largest was assessed in one study in 13 licenced premises, with no evident effect. Reducing the size of wine glasses in restaurants decreased wine sales by 7.3% (95% CI −13.5%, −1.5%) in a mega-analysis of eight datasets from studies in five licensed premises. Using smaller wine glasses at home may also reduce consumption, but the evidence from just one study is less certain. No studies have assessed the impact of glass size for drinking beer. The effect of bottles smaller than the standard 750 mL on wine consumed at home was assessed in two studies: 500 mL bottles reduced consumption by 4.5% (95% CI −7.9%, −1.0%) in one study, but in another, using 375 mL bottles there was no evident effect. No studies assessed the impact of bottle or other container size for drinking beer. Reducing the size of servings, glasses and bottles could reduce wine consumption across populations. The impact of similar interventions for reducing consumption of other alcoholic drinks awaits evaluation. Further studies are also warranted to assess the generalisability of existing evidence.
... The study was powered to detect an effect based on the observed effect of 50-cl bottles [17], which may be larger than any effect of drinking from 37.5-cl bottles. Smaller bottles-whether 50 or 37.5 clmight reduce consumption by making additional wine intake more effortful [16], or reflecting the tendency for people to consume a specific number of units-such as bottles-in any one episode of T A B L E 3 Mixed-effect regression model estimates (95% CI) for volume (ml) of wine consumed per 14-day period (n = 217) consumption regardless of container size [33]. Smaller bottles might also increase consumption by reducing barriers to consumption that are present for larger sizes [19], or as a result of being considered too small. ...
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Background and aims: Reducing alcohol consumption across populations would decrease the risk of a range of diseases, including many cancers, cardiovascular disease and Type 2 diabetes. The aim of the current study was to estimate the impact of using smaller bottles (37.5- versus 75-cl) and glasses (290 versus 370 ml) on consuming wine at home. Design: Randomized controlled trial of households with cross-over randomization to bottle size and parallel randomization to glass size. Setting: UK households. Participants: A total of 260 households consuming at least two 75-cl bottles of wine each week, recruited from the general population through a research agency. The majority consisted of adults who were white and of higher socio-economic position. Intervention: Households were randomized to the order in which they purchased wine in 37.5- or 75-cl bottles, to consume during two 14-day intervention periods, and further randomized to receive smaller (290 ml) or larger (350 ml) glasses to use during both intervention periods. Measurements: Volume (ml) of study wine consumed at the end of each 14-day intervention period, measured using photographs of purchased bottles, weighed on study scales. Findings: Of the randomized households, 217 of 260 (83%) completed the study as per protocol and were included in the primary analysis. There was weak evidence that smaller bottles reduced consumption: after accounting for pre-specified covariates, households consumed on average 145.7 ml (3.6%) less wine when drinking from smaller bottles than from larger bottles [95% confidence intervals (CI) = -335.5 to 43. ml; -8.3 to 1.1%; P = 0.137; Bayes factor (BF) = 2.00]. The evidence for the effect of smaller glasses was stronger: households consumed on average 253.3 ml (6.5%) less wine when drinking from smaller glasses than from larger glasses (95% CI = -517 to 10 ml; -13.2 to 0.3%; P = 0.065; BF = 2.96). Conclusions: Using smaller glasses to drink wine at home may reduce consumption. Greater uncertainty remains around the possible effect of drinking from smaller bottles.
... This effect is consistent across all BMI levels (Rolls et al., 2002;Marchiori et al., 2011). Conscious as well as subconscious factors or mechanisms responsible for influencing the Portion-Size-Effect include unit bias (Geier et al., 2006), expected satiety (Brunstrom and Rogers, 2009), energy compensation (Benton, 2015), bite-size (Almiron-Roig et al., 2018), visual stimuli (Marchiori et al., 2011;Penaforte et al., 2014), financial aspects (Benton, 2015;Steenhuis and Poelman, 2017), and portion norms (Lewis et al., 2015). In the context of Portion-Size-Effect, the subconscious mechanisms are reflected in the lack of differentiation when people eat from a large portion versus a small portion, despite consuming more (Levitsky and Youn, 2004) even after being informed about the difference in portions sizes (Spanos et al., 2015;Reily et al., 2016). ...
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Portion sizes of meals have been becoming progressively larger which contributes to the onset of obesity. So far, little research has been done on the influence of body weight on portion size preferences. Therefore, we assessed whether Body Mass Index (BMI), as well as other selected factors, contribute to the estimation of food portions weight and the subjective perception of portion sizes. Through online questionnaires, the participants were asked to estimate the weight of pictured foods in the first study. In the second study, the participants indicated how the depicted varying portion sizes of different meals relate to their actual consumed real-life portion sizes. A total of 725 and 436 individuals were included in the statistical analysis in the first and second study, respectively. BMI and gender had a small effect on the capacity to estimate the weight of foods. The main predictor for portion size choices was the factor gender with men estimating ideal portion sizes as larger than women. Further, age and hunger together with external and restrictive eating behaviors were among the deciding factors for portion size choices. As expected, externally motivated eaters chose bigger portions while restrictive individual smaller ones. Gender- and age-related differences in portion size preferences likely reflect distinct energy requirements. The individuals with a higher BMI do not differ strongly from other BMI groups in their portion-related preferences. Therefore, other factors such as meal frequency, snacking, or a lifestyle, may contribute more to the onset, development, and maintenance of overweight.
... Conversely, Westerners tend to eat separately, and each person is assigned a limited amount of food on their plate. Third, cultural norms influence portion sizes [80,81]. China is influenced by collectivism. ...
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The COVID-19 pandemic threatens global food security and has created an urgent need for food conservation. This article presents a review of clean plate campaigns around the world. It aims to fight food waste and reveal the factors that may influence food waste. The Clean Plate Club in the US developed during wartime and relied heavily on political power for compliance, whereas the Clean Plate movement in South Korea was based on religion. China’s Clean Your Plate Campaign (CYPC) has gone through two stages: CYPC I and CYPC II. The latter occurred during the unstable period of the COVID-19 pandemic. It was large-scale and more strongly enforced than CYPC I. In China, CYPC has relied more on personal virtue than on politics or religion. Culture, policy, COVID-19, and behavior are all important social factors that influence food waste. Specifically, two cultural values are drivers of food waste in China: hospitality and face-saving (mianzi). In terms of policy, China's food waste law mainly relies on persuasion; it lacks any power of enforcement. Laws in France and Italy, by contrast, focus on re-using food and involve both coercion and incentives. COVID-19 may have led to panic purchasing and stockpiling, but, in general, it has resulted in a reduction in food waste.
... Interestingly, this impact has been observed with packaged snacks (35), energy-dense casseroles (36,40), unit foods like sandwiches (44) and beverages (45), and even with low energy-dense foods like fruits and vegetables. Additionally, the effect of PS has been also observed in restaurants and offices (46,47), even if participants were served unpalatable foods (48) or with manipulation of plate size (49). To systematically assess the effect of PS on energy intake, several studies were conducted (Table I). ...
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Introduction: The purpose of this narrative review is to provide evidence for the impact of food portion sizes on the development of obesity in children and adolescents. Strategies are needed on portion size estimation and on the relationship of portion size with certain health problems such as obesity, insulin resistance, and emotional eating in all age groups, in order to provide information for parents, teachers, and health professionals aiming to promote healthy eating. A wide range of controlled laboratory studies have found that portion size (PS) had the strongest effect on the amount of food consumed. The effect of PS on total energy intake has been already observed with different types of foods and beverages, especially with energy-dense foods. The influence of large PS was persistent and happened regardless of demographic characteristics such as age, gender, income level, or body mass index. Although a direct causal link between PS and obesity remains controversial, some health and dietetics organizations recommend to moderate PS, especially for energy-dense foods. Research studies in both laboratory and free-living contexts are needed to determine the causal link between increased PS, obesity, and related metabolic complications in children and adolescents.
... The implication is that individuals who are less sensitive to stimulus reduction are more sensitive to stimulus increment, and vice versa. While these findings are highly novel in terms of chemosensory capacity, such asymmetrical sensitivities to high-versus low-stimulus intensities are in line with findings from comparable auditory (Geier, Rozin, & Doros, 2006;Kerameas et al., 2015;Rinne et al., 2006) and visual (Blundell & Gillett, 2001;Rizk & Treat, 2015;Robinson et al., 2016) analyses. Altogether, these findings highlight the importance of treating d ′ (t) , d ′ (d) , and d ′ (i) as independent measures. ...
Article
Signal detection theory provides a comprehensive psychophysical framework that enables accurate estimates of individual sensitivity for discriminating stimulus intensities (d′(t)). The present study aims to explore differences in d′ measures for decremental (d′(d)) and incremental stimulus range (d′(i)) in relation to the traditional measure of d′(t). These measures were also assessed for their capabilities in segregating sensitivity groups and identifying links to body adiposity. A total of 70 healthy Caucasian males (21-39 years; BMI ranges 20.5-48.1 kg∙m⁻²) performed sensory difference tasks (i.e., 2AFC Method of Constant Stimuli over 10 concentrations) for 3 odours (O1-O3) and 3 tastants (T1-T3) across 6 sessions. Individual participant performance was used for computing d′(t), d′(d), and d′(i) for separate stimuli. Pearson’s correlations and multivariate analyses (k-means clustering, PCA varimax rotation) were applied to test for relationships across these sensitivity measures. Additionally, correlations between individual d′(t), d′(d), d′(i) versus BMI were assessed. The results revealed consistently significant positive correlations of d′(d) and d′(i) measures with d′(t) (p<0.05). Additionally, d′(d) and d′(i) were negatively correlated for O1, T1, and T3. Furthermore, only d′(d) and d′(i) were able to produce low versus high sensitivity clusters. The PCA varimax rotation showed a clear separation for the gustatory and olfactory stimuli only when d′(d) was used. With regards to BMI, d′(t) and d′(i) showed negative correlations for O1, O2, and T3, whereas d′(d) yielded positive correlations for O1, and T3 (p<0.05). Overall, these findings suggest that d′(d) represents an independent measure that could offer distinctive insights into individual chemosensory sensitivities.
... This hypothesis was, however, based on just one previous study [21] which found that wine consumption was higher from 75 cl bottles, compared to 50 cl bottles. The mechanisms for this effect are unknown but one possibility is that it may reflect the tendency for people to consume in 'units' [33], with one bottle-regardless of size-comprising one unit. In keeping with this explanation, when consuming wine from a bottle, a drinking episode-e.g. a meal or an evening-would be considered complete when the bottle is empty. ...
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Background The physical properties of tableware could influence selection and consumption of food and alcohol. There is considerable uncertainty, however, around the potential effects of different sizes and shapes of tableware on how much food and alcohol people self-serve. These studies aimed to estimate the impact of: 1. Plate size and shape on amount of food self-served; 2.Wine glass and bottle size on amount of wine self-poured. Methods 140 adults participated in two laboratory studies—each using randomised within-subjects factorial designs—where they self-served food (Study 1) and wine (Study 2): Study 1: 3 plate sizes (small; medium; large) × 2 plate shapes (circular; square). Study 2: 3 wine glass sizes (small; medium; large) × 2 wine bottle sizes (75 cl; 50 cl). Results Study 1: There was a main effect of plate size: less was self-served on small (76 g less, p < 0.001) and medium (41 g less, p < 0.001) plates, compared to large plates. There was no evidence for a main effect of plate shape (p = 0.46) or a size and shape interaction (p = 0.47). Study 2: There was a main effect of glass size: less was self-served in small (34 ml less, p < 0.001) and medium (17 ml less, p < 0.001) glasses, compared to large glasses. There was no evidence of a main effect of bottle size (p = 0.20) or a glass and bottle size interaction (p = 0.18). Conclusions Smaller tableware (i.e. plates and wine glasses) decreases the amount of food and wine self-served in an initial serving. Future studies are required to generate estimates on selection and consumption in real world settings when numerous servings are possible. Protocol registration information: OSF (https://osf.io/dj3c6/) and ISRCTN (https://doi.org/10.1186/ISRCTN66774780).
... ; https://doi.org/10.1101/2021.08.23.21262191 doi: medRxiv preprint than men? Besides a multitude of potential lifestyle factors, we wish to indicate a behavioural one associated with a particular cognitive bias -the "unit bias" [76]. This bias is such that people seem to think that a unit of some entity (with certain constraints) is the appropriate and optimal amount. ...
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Obesity (and the consequent obesity epidemic) is a complex, adaptive process, taking place over a time span of many years. Energy intake is recognized as a potentially important driver of obesity, especially in the context of an identifiable energy imbalance which, it is surmised, must lead to weight gain. Similarly, energy expenditure must play an important role. However, both show an enormous degree of individual variation. Therefore, measuring them is an exceedingly difficult task, especially in the context of large populations and long time periods. It has been argued that population-level observed weight gain can be traced back to very small daily energy imbalances while, at the same time, positing that a much larger maintenance energy gap is responsible for maintaining the energy requirements of the increased weight population. In this paper we examine the relation between BMI and energy intake as functions of age. The convexity of the BMI curves as a function of age and gender demonstrate the enhanced obesity risk apparent in young adults and women, and imply that no settling points exist at the population level. Consistent with other studies, overall weight increases are consistent with a very small daily energy imbalance, about 7 cal. Consumption as a function of age shows a small, steady, linear decrease of about 8 cal per year, and can be associated with a maximal energy excess/deficit of about 250cal for the youngest and oldest age groups. By examining weight differences between age groups as a function of age, we argue that this excess/deficit is an important motor for the observed weight differences, and argue that the apparent energy imbalance of 250 cal, due to excess consumption, leads to an effective imbalance of only 7 cal due to the existence of various physiological and behavioral mechanisms that enhance weight homeostasis and effectively reduce the energy excess from 250 cal to 7 cal. We discuss several possibilities for such mechanisms.
... Prior research on partitioning suggests that the unit labels to describe portions (e.g., Geier, Rozin, & Doros, 2006) and other partition cues (e.g., Red Potato Chips; Geier, Wansink, & Rozin, 2012) can dramatically decrease consumption. Partitioning effects have been proposed to operate by increasing transaction costs associated with consumption, whereby smaller partitions rather than larger aggregates provide more decision-making opportunities that enable people to better constrain their consumption (Cheema & Soma, 2008). ...
Thesis
This dissertation examines how and why social contexts moderate gaps between people’s aspirations and attainment. The broader aim is to understand how contexts moderate the motivational and goal pursuit processes that contribute to social disparities. I examine these processes across 10 studies drawn from three empirical papers. First, I present eight experiments documenting how and why different ways of framing goal-relevant information influences people’s motivation and behavior such as when they begin saving for future events and how much unhealthy food they consume (“When Does the Future Begin? Time Metrics Matter, Connecting Present and Future Selves”: Lewis & Oyserman, 2015; “Seeing More and Eating Less: Effects of Information Granularity on the Perception and Regulation of Food Consumption: Lewis & Earl, in press). Second, I present a field experiment documenting that the stereotypes that are activated in public health clinics can undermine African American patients’ willingness to pay attention to stigmatizing health information (“African American Patients’ Attention to Health Information is Influenced by In-Group Peers in Health Clinics”: Lewis, Kougias, & Earl, 2017). Third, I present a national survey documenting that people’s interpretations of experienced difficulty (an important motivational construct) are influenced by their positions in the social hierarchy – indexed by the interaction between their race and level of education (“No pain, no gain? Social demographic correlates and identity consequences of interpreting experienced difficulty as importance”: Aelenei, Lewis, & Oyserman, 2017). Together, the 10 studies in this dissertation converge to suggest that if we wish to understand and address social disparities, researchers and practitioners must consider the interplay between social context and identity, and how it influences motivation and goal pursuit processes.
... When people get their own individual portion, they are more likely to finish it. This phenomenon is known as the unit-bias heuristic which refers to the tendency of individuals to view a single entity as the appropriate amount to consume or consider (Geier et al., 2006;Van Kleef et al., 2014). The vegetables may also be more visible as they are in front of the person, which could make them more attractive or tempting to eat. ...
Article
Purpose Snacks at work are often of poor dietary quality. The main objective of the current study is to examine the effect of making vegetable snacks available at workplace meetings on consumption. Design/methodology/approach In three between-subjects field experiments conducted at a hospital and three ministries in the Netherlands, with meeting as the unit of condition assignment, attendees were exposed to an assortment of vegetables, varying in vegetable variety and presence of promotional leaflet in study 1 ( N = 136 meetings), serving container in study 2 ( N = 88 meetings) and additional presence of cookies in study 3 ( N = 88 meetings). Consumption of vegetables and cookies was measured at meeting level to assess grams consumed per person. Findings Across the three studies, average consumption per meeting attendee was 74 g (SD = 43) for study 1; 78 g (SD = 43) for study 2 and 87 g (SD = 35) for study 3. In the first study, manipulation of perceived variety and information leaflets did not affect intake. In the second study, significantly more vegetables were eaten when they were offered in single sized portions ( M = 97 g, SD = 45) versus in a shared multiple portions bowl (63 g, SD = 38) ( p < 0.001). In the third study, no effect was found of the additional availability of cookies on vegetable consumption during the meeting. Practical implications The present studies show how availability of vegetables at unconventional occasions makes meeting attendants consume considerable portions of vegetables on average. As such, offering healthy snacks at the workplace may be a valuable part of workplace health promotion programs and positively change the “office cake culture”. Originality/value Vegetable intake is less than recommended in many countries worldwide. Many snacking occasions are at work, which makes office meetings a potential consumption occasion to encourage vegetable intake. Hence, the aim of this study is to examine whether free availability of vegetable snacks during meetings contributes to their consumption among meeting attendees and under what conditions consumption is optimal.
... It should be noted that our approach to measure environmental impacts used standardized portion sizes because we were particularly interested in ingredient replacements. A powerful alternative would be to stimulate reduced portion sizes (De Boer et al., 2014;Geier et al., 2006). Further research could combine both approaches, which would also allow for detecting spillover effects (i.e. ...
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A shift to more sustainable diets is needed to ensure food security and to reduce the pressure on the environment. Yet, many consumers have misconceptions about the environmental impacts of their diets and lack knowledge on how to prepare sustainable meals. This study uses a mixed-methods approach to develop four information nudges and to test their impact on dietary choices among a representative sample of Dutch consumers. A 2 × 2 between-subjects design crossing type of information (procedural versus declarative) with type of impacts (health versus environmental) is applied. The environmental impact is measured in terms of CO2 emissions, land use and water use. We find that pre-intervention knowledge about sustainable or healthy diets is related to the sustainability of participants’ dietary choices. Procedural knowledge on how to prepare a healthier meal has the greatest potential to influence dietary behavior, in particular for participants without prior self-reported dietary restrictions.
... Foods that are pre-portioned such as snacks and ready-to-eat meals can be perceived as an appropriate amount to consume in their entirety [36]. Therefore, consumption of these foods is likely largely determined by Planned Amount. ...
Article
Satiation has been described as a process that leads to the termination of eating and controls meal size. However, studies have shown that the termination of eating can be influenced by multiple behavioral and biological processes over the course of a meal as well as those related to the context in which the meal is consumed. To expand understanding of how individuals experience satiation during a meal, we recently developed the Reasons Individuals Stop Eating Questionnaire (RISE-Q). The development of the RISE-Q revealed five distinct factors reported to contribute to meal termination: Planned Amount, Self-Consciousness, Decreased Food Appeal, Physical Satisfaction, and Decreased Priority of Eating. Thus, we define satiation as a series of dynamic processes that emerge over the course of a meal to promote meal termination. We suggest that each of the factors identified by the RISE-Q represents a distinct process, and illustrate the contribution of each process to meal termination in the Satiation Framework. Within this framework the prominence of each process as a reason to stop eating likely depends on meal context in addition to individual variability. Therefore, we discuss contexts in which different processes may be salient as determinants of meal termination. Expanding the definition of satiation to include several dynamic processes as illustrated in the Satiation Framework will help to stimulate investigation and understanding of the complex nature of meal termination.
... It should be noted that our approach to measure environmental impacts used standardized portion sizes because we were particularly interested in ingredient replacements. A powerful alternative would be to stimulate reduced portion sizes (Geier et al., 2006;De Boer et al., 2014). Further research could combine both approaches, which would also allow for detecting spillover effects (i.e. ...
Article
A shift to more sustainable diets is needed to ensure food security and to reduce the pressure on the environment. Yet, many consumers have misconceptions about the environmental impacts of their diets and lack knowledge on how to prepare sustainable meals. This study uses a mixed-methods approach to develop four information nudges and to test their impact on dietary choices among a representative sample of Dutch consumers. A 2x2 between-subjects design crossing type of information (procedural versus declarative) with type of impacts (health versus environmental) is applied. The environmental impact is measured in terms of CO2 emissions, land use and water use. We find that pre-intervention knowledge about sustainable or healthy diets is related to the sustainability of participants' dietary choices. Procedural knowledge on how to prepare a healthier meal has the greatest potential to influence dietary behavior, in particular for participants without prior self-reported dietary restrictions.
... ). levels of adherence to codes (Galbraith-Emami and Lobstein, 2013[104]). A review of the effectiveness of the CFBAI noted that while all companies met their respective pledges, 80.5% of food advertisements aired during children's programming still promoted nutritionally deficient products(Kunkel, Castonguay and Filer, 2015[101]). ...
Chapter
This chapter explores the impact that obesity policies can have on the food and drink industry. It presents the results of a literature review on six public health policies that directly affect the food industry: reformulation, portion size changes, food labelling, food taxes, advertising restrictions and healthy food subsidies. It considers both one-off implementation costs, as well as on-going changes in operations or sales.
... Support for this theorizing comes from prior research examining how the size of units (i.e., one large unit versus several smaller units) affects judgments and behavior. For example, in the food domain, research on unit bias has found that people consume more food as the size of the food unit increases (Geier et al. 2006). That is, people focused more on the unit amount than on the absolute magnitude that unit represents. ...
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Consumers monitor their goal progress to know how much effort they need to invest to achieve their goals. However, the factors influencing consumers' goal progress monitoring are largely unexamined. Seven studies (N ¼ 8,409) identified categorization as a novel factor that influences goal progress perceptions, with consequences for motivation. When pursuing a goal, categorization cues lead consumers to perceive that their goal-relevant actions are in separate categories; as a result, consumers anchor their estimates of goal progress on the proportion of categories completed and are less affected by the absolute amount of progress made than when categorization cues are not present. As a result, depending on the proportion of categories completed, categorization can lead consumers to infer greater progress when they are actually farther from their goal, and to infer less progress when they are closer to their goal. We demonstrate consequences of this effect for consumers' motivation and goal attainment in incentive compatible contexts.
... Amorphous dishes, or those without a clearly defined shape, were used in early studies (e.g., Rolls et al. 2002;Diliberti et al. 2004). This reduces the likelihood of the effect being driven by a unit bias, whereby individuals might be motivated to consume full amounts of foods served in discrete units or segments, such as a bag of chips or sandwiches (Geier et al. 2006), or by demand characteristics resulting from noticeable differences in the amount served (Slawson and Eck 1997). Use of amorphous foods was helpful in establishing the PSE, but it is important to determine the generalizability to other types of foods. ...
... Regarding sales by the glass, any effect of glass size on consumption may be driven by perceptual effects. People tend to consume in units; for example, having one cup of coffee, one slice of cake or one glass of wine-known as the unit bias heuristic [8]. The same portion size in a larger glass appears smaller than when presented in a smaller glass [9]. ...
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Aim: To estimate the effects of wine glass size on volume of wine sold in bars and restaurants. Design: A mega-analysis combining raw (as opposed to aggregate-level) data from eight studies conducted in five establishments. For each dataset, a multiple treatment reversal design was used, with wine glass size changed fortnightly whilst serving sizes were unaffected, in studies lasting between 14 and 26 weeks SETTING AND PARTICIPANTS: Five bars and restaurants in England participated in studies between 2015 and 2018, using wine glasses of five sizes: 250ml, 300ml, 370ml, 450ml and 510ml, with the largest size only used in bars. Measurements: Daily volume of wine sold by the glass, bottle or carafe for non-sparkling wine were recorded at bars (594 days) and restaurants (427 days), averaging four months per study. Findings: Mega-analysis combining data from bars did not find a significant effect of glass size on volume of wine sold compared with 300ml glasses: the volume of wine sold using 370ml glasses was 0.5% lower (95%CI -8.1% to 6.1%), using 450ml glasses was 1.0% higher (95%CI -9.1 to 12.2), and using 510ml glasses was 0.4% lower (95% CI -9.4 to 9.4). For restaurants, compared with 300ml glasses, the volume of wine sold using 250ml glasses did not show a significant difference: 9.6% lower (95% CI -19.0 to 7.2). Using 370ml glasses the volume of wine sold was 7.3% higher (95%CI 1.5% to 13.5%); no significant effect was found using 450ml glasses: 0.9% higher (95%CI -5.5 to 7.7). Conclusions: The volume of wine sold in restaurants in England may be greater when 370ml glasses are used, compared with 300ml wine glasses, but may not be in bars. This might be related to restaurants compared with bars selling more wine in bottles and carafes, which require free-pouring.
... The most widely reported human bias related to portion size is unit bias, or the belief that a single unit is an appropriate amount to eat. 178 Such beliefs may result in people consuming more when food is served in a larger unit (e.g. king size chocolate bar) than in a smaller unit (regular or bite size bar), and has been proposed as a potential explanation for the portion-size effect. ...
Article
Context: Overestimation or underestimation of portion size leads to measurement error during dietary assessment. Objective: To identify portion size estimation elements (PSEEs) and evaluate their relative efficacy in relation to dietary assessment, and assess the quality of studies validating PSEEs. Data selection and extraction: Electronic databases, internet sites, and cross-references of published records were searched, generating 16 801 initial records, from which 334 records were reviewed and 542 PSEEs were identified, comprising 5% 1-dimensional tools (eg, food guides), 46% 2-dimensional tools (eg, photographic atlases), and 49% 3-dimensional tools (eg, household utensils). Out of 334 studies, 21 validated a PSEE (compared PSEE to actual food amounts) and 13 compared PSEEs with other PSEEs. Conclusion: Quality assessment showed that only a few validation studies were of high quality. According to the findings of validation and comparison studies, food image-based PSEEs were more accurate than food models and household utensils. Key factors to consider when selecting a PSEE include efficiency of the PSEE and its applicability to targeted settings and populations.
... Research suggests that changing the portion sizes of meat and plant ingredients in a dish will influence how much of each is eaten, and that this happens without diners realizing that they have consumed a different amount from normal or feeling unsatisfied with what they have eaten (Labbé et al. 2018). This phenomenon is known as "unit bias," which means diners tend to believe the original portion size they are given is the appropriate amount, even if this is so large it leaves them overfull (Geier et al. 2006). ...
... For example, an increase in the size of the food unit can induce an increase in chewing for proper bolus formation, resulting in a subsequent reduction of food intake. On the other hand, manipulating food unit segmentation can also induce the so-called "unit bias" leading subjects to consume a set number of food units (Geier, Rozin & Doros, 2006). ...
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The use of clinical trials to demonstrate effect of foods consumption on human health has increased significantly in recent years at the global level. As in other areas of human health, some authors choose to use parallel trial designs, while others prefer to use crossover designs for these trials. Because crossover trials have the advantage of reducing the number of subjects needed and the economic cost to be performed, they have many advocates within the scientific community. However, these types of tests also have numerous drawbacks, due to the difficulty of carrying out adequate statistical analyses, the lack of reliable standards adapted to them or confounding factors. In this chapter, the advantages and disadvantages of crossover designs and whether they are a recommended option for human nutrition research are shown. The usefulness of design of experiments coupled to crossover trials, especially when comparing various levels of the dependent variable, are also discussed.
... Frequency of occurrence is a criterion used to establish the validity of a statement. -Unit bias (Geier et al. 2006). People tend to give equal weight to each condition at the expense of detailed scrutiny of its actual weight. ...
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It is conventional wisdom in machine learning and data mining that logical models such as rule sets are more interpretable than other models, and that among such rule-based models, simpler models are more interpretable than more complex ones. In this position paper, we question this latter assumption by focusing on one particular aspect of interpretability, namely the plausibility of models. Roughly speaking, we equate the plausibility of a model with the likeliness that a user accepts it as an explanation for a prediction. In particular, we argue that—all other things being equal—longer explanations may be more convincing than shorter ones, and that the predominant bias for shorter models, which is typically necessary for learning powerful discriminative models, may not be suitable when it comes to user acceptance of the learned models. To that end, we first recapitulate evidence for and against this postulate, and then report the results of an evaluation in a crowdsourcing study based on about 3000 judgments. The results do not reveal a strong preference for simple rules, whereas we can observe a weak preference for longer rules in some domains. We then relate these results to well-known cognitive biases such as the conjunction fallacy, the representative heuristic, or the recognition heuristic, and investigate their relation to rule length and plausibility.
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Evidence demonstrates that food packaging attracts consumers to purchase and has the potential to nudge consumers towards healthy choices, including reducing portion size. However, food purchasing decisions are often automatic and packaging features may go unnoticed. Therefore, it is important to understand what consumers identify as most salient about packaging: what they notice and why, and which elements might nudge consumers towards healthy options and smaller portions of high‐energy‐density foods. This study explored consumer perception of food packaging, investigated specific features associated with portion control and elicited design ideas to improve packaging for healthy eating and downsizing. A qualitative approach was adopted applying a participant‐driven photo‐elicitation (PDPE) task with in‐depth interviews. Participants were 25 adults living in the UK (aged 20–32 years; 17 females, 8 males, x¯$$ \overline{\mathrm{x}} $$BMI = 23 kg/m2). Participants took photographs of 10 food packages according to salience (n = 5) and portion control (n = 5). These were uploaded to a secure site and then discussed at the interview, which was transcribed and analysed. The salience of packaging was described in terms of trust building, stimulating appetite and relating to self‐identity, whereas for portion control, themes included structural reminders, healthy prompts and portion awareness. Packaging can be designed to make health value or serving size more salient by prompting portion control and increasing the attractiveness of packaging. While food purchase decisions happen with little deliberation, when probed, consumers provide useful insights for packaging design to assist portion control.
Article
Serving larger portions leads to increased food intake, but behavioral factors that influence the magnitude of this portion size effect have not been well characterized. We investigated whether measures of eating microstructure such as eating rate and bite size moderated the portion size effect. We also explored how sensory-specific satiety (SSS; the relative hedonic decline of a food as it is eaten) was affected by eating microstructure and larger portions. In a randomized crossover design, 44 adults aged 18–68 y (66% women; 46% with overweight and obesity) ate lunch in the laboratory once a week for 4 weeks. The meal consisted of pasta that was varied in portion size (400, 500, 600, or 700 g) and 700 g of water. Meals were video-recorded to assess bite count and meal duration, which were used to calculate mean eating rate (g/min) and mean bite size (g/bite). At each meal participants also completed an assessment of SSS. The results showed that as larger portions were served, meal intake increased in a curvilinear manner (p < 0.0001). Measures of eating microstructure did not moderate the portion size effect but were related to intake across all portions; faster eating rate, larger bite size, higher bite count, and longer meal duration were associated with greater consumption at all meals (all p < 0.0001). SSS was not influenced by any measure of eating microstructure or by portion size (all p > 0.10). In summary, the portion size effect was not moderated by eating microstructure, but relatively faster eating rates and larger bite sizes at meals, along with large portions, combined to increase food intake.
Chapter
In diesem Kapitel begleiten wir einen Pendler auf dem Nachhauseweg. In der halben Stunde, die er im Stau steht, gehen ihm so einige Dinge durch den Kopf, und dies bietet eine Steilvorlage für die Analyse von kognitiven Effekten im Alltagsleben. Denn derartige Verzerrungen, die auf der intuitiven (und nicht immer korrekten) Einschätzung der Lage basieren, sind keineswegs selten, und vor diesem Hintergrund kommen die ersten 42 von über 300 im Buch diskutierten Fehlleistungen zur Sprache. So konnte der Pendler als Opfer des Planungsfehlschlusses erst zu spät seinen Heimweg antreten, und mit Blick auf sein Verbraucherverhalten betrachtet er sich gegenüber dem Einfluss von Werbung als immun – trotz Framing und Priming, Kognitiver Leichtigkeit und Wiedererkennungsheuristik. Darüber hinaus beschäftigen ihn die Möglichkeiten zur Geldanlage; Aktienprämienrätsel und Verfügbarkeitsverzerrung sind nur zwei Beispiele für damit verbundene Irrtümer. Konservatismusfehlschluss, Verlustaversion und Status-quo-Verzerrung bilden ein Trio infernal, das vielen notwendigen Weiterentwicklungen und Weichenstellungen im Weg steht, die in späteren Kapiteln beleuchtet werden.
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Food consumption and its physiological, psychological, and social antecedents and outcomes have received considerable attention in research across many disciplines, including consumer research. Although researchers use various methods to examine food decision-making, many insights generated stem from observing eating choices in tightly controlled lab settings. Although much insight can be gained through such studies (or “lab eating”), it is apparent that many factors differ between such settings and everyday consumption (or “free-living eating”). This article highlights key differences between “lab eating” and “free-living eating,” discusses ways in which such differences matter, and provides recommendations for researchers regarding how and when to narrow the gap between them, including by enriching lab studies in ways inspired by free-living eating. Besides suggesting how researchers can conduct studies offering a deeper understanding of eating patterns, we also highlight practical implications for improving food consumption for consumers, marketers, and policymakers.
Article
Food serving sizes are on the rise and this increase is one factor contributing to both obesity and food waste. Hence, reducing serving size is a potentially effective strategy for lessening overconsumption and food waste—but it carries the risk that consumers may perceive the smaller serving size as too small, lowering satisfaction. This research examines the role of serving size, unit size, and self-serving on the amount of food served, consumed, and wasted, with the main objective of reducing both overconsumption and food waste while maintaining consumer satisfaction. Across four experiments, we demonstrate that consumers who are served food in smaller units consume less but waste more, while consumers who serve themselves food in smaller units consume less and waste less. When self-serving food in smaller units, consumers benefit from pause moments providing decision-making opportunities that draw attention to the serving decision, as reflected in longer serving times and greater overestimation of the served amount of food. Consequently, consumers presented with smaller unit sizes serve themselves less food—resulting in decreased consumption and waste, without lessening consumer satisfaction. These findings offer a wide range of win-win implications that are of relevance to consumers as well as to managers of restaurants, food services, and health professionals.
Article
Energy intake is the product of portion size (PS)-the energy content of an ingestive event-and ingestive frequency (IF)-the number of ingestive events per unit time. An uncompensated alteration in either PS or IF would result in a change in energy intake and body weight if maintained over time. The objective of this meta-analysis was to assess the independent effects of PS and IF on energy intake and body weight among healthy adults in randomized controlled trials (RCTs). A total of 9708 articles were identified in PubMed, Web of Science, Cochrane, and CINAHL databases. The articles were divided among 10 researchers; each article was screened for eligibility by 2-3 independent reviewers. Exclusion criteria included: populations <19 y and >65 y, unhealthy populations (i.e. participants with an acute or chronic disease), assessments <24 h and <4 wk in duration for trials investigating energy intake or body weight, respectively. Controlled feeding trials (i.e. fixed energy intake) that manipulated IF and PS in the same study intervention (IF/PS) were evaluated separately and for the body weight outcome only. Twenty-two studies (IF = 4, PS = 14, IF/PS = 4) met the inclusion criteria. There was an insufficient number of studies to assess the effect of IF, PS, or IF/PS on body weight. There was heterogeneity in the effect sizes among all comparisons (I2 ≥75%). Consuming larger portion sizes was associated with higher daily energy intake [295 kcal (202, 388), n = 24; weighted mean differences (WMD) (95% CI), n = comparisons], and increased frequency of ingestive events was associated with higher energy intake [203 kcal (76, 330), n = 10]. Results from RCTs support that larger PS and greater IF are both associated with higher energy consumption. However, there is insufficient information to determine chronic effects on body weight. This protocol was registered at the International Prospective Register of Systematic Reviews (PROSPERO) as CRD42018104757.
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A same-brand bottled food sold by competing retailers may be produced in different countries. This investigation offers an empirically-based view of how consumers evaluate a bi-national bottled food product which carries a brand associated with a developed country but is manufactured in a developing country, as opposed to its home-country-made variants; and also seeks to identify extrinsic product cues which may moderate their responses. Results show that perceived quality erodes because of an off-putting COM image, while a short shelf life improves its evaluation. Such effect, however, is limited to small-size and glass packaging. In addition, shoppers’ product quality perceptions raise their willingness to pay.
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Objetivo: Evaluar la efectividad de incluir información nutricional y de propiedades de los alimentos en un comedor universitario de Salamanca (España), para promover las conductas alimentarias saludables. Diseño: Estudio experimental y correlacional transversal. Emplazamiento: Comedor universitario de Salamanca (España). Participantes: En el experimento se recogió información de la elección de 1.122 menús por parte de estudiantes universitarios. El cuestionario fue respondido por 48 estudiantes universitarios que participaron en el experimento. Medidores principales: Metodología mixta (experimento de campo y cuestionario en línea). La variable independiente fue la inclusión o no de información nutricional de los menús. Con el cuestionario se evaluó la actitud de los estudiantes sobre este tipo de herramientas. Resultados: El experimento muestra una mejora en la dieta de los estudiantes universitarios con la inclusión de elementos informativos que apelan a la elección más saludable, aumentando su consumo de fruta, verduras, legumbres, pescado y carne blanca. Los encuestados mostraron un alto grado de receptividad de estas herramientas para la promoción de la salud. A pesar de esto, su autopercepción de mejoría de la dieta era más optimista que lo cuantificado en el experimento. Los estudiantes universitarios muestran un grado de aprobación muy alto frente a otras herramientas de promoción de alimentación saludable, especialmente aquellas de carácter educativo e informativo. Se comprobó que una preocupación mayor por la dieta estaba asociada con un mayor apoyo de estas herramientas. Conclusión: Existe una mejora en la alimentación de los estudiantes universitarios y una actitud positiva frente a herramientas de promoción de la salud, especialmente por parte de quienes tienen una autopercepción más saludable. Es necesario emplear nuevas herramientas basadas en las ciencias conductuales en la promoción de la salud, por parte de la industria privada y las entidades públicas. ABSTRACT Objective: To evaluate the effectiveness of including nutritional and food properties information in a university canteen in Salamanca (Spain) to promote healthy eating behaviours. Design: Experimental and correlational cross-sectional study. Location: University Dining Hall of Salamanca (Spain). Participants: In the experiment, information was collected on the choice of 1122 menus by university students. The questionnaire was answered by 48 university students who participated in the experiment. Main measurements: Mixed methodology (field experiment and online questionnaire). The independent variable was the inclusion or not of nutritional information from the menus. The questionnaire was used to evaluate the students’ attitude towards this type of tool. Results: The experiment shows an improvement in the diet of university students with the inclusion of information elements that appeal to the healthiest choice, increasing their consumption of fruit, vegetables, legumes, fish and white meat. The students surveyed showed a high degree of receptivity to these health promotion tools. Despite this, their self-perception of dietary improvement was more optimistic than that quantified in the experiment. University students showed a very high degree of approval of other health promotion tools, especially those of an educational and informative nature. A greater concern for diet was associated with greater support for these tools. Conclusion: There is an improvement in the diet of university students and a positive attitude towards health promotion tools, especially by those with a healthier self-perception. There is a need for new tools based on behavioural sciences in health promotion by private industry and public entities.
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Der Beitrag gibt einen Überblick über zentrale Entwicklungslinien der ernährungsbezogenen Verbraucherforschung und arbeitet dabei eine Tendenz zur zunehmenden Eingriffstiefe des Staates als Reaktion auf individuelle und gesellschaftliche Problemlagen heraus. Deutlich wird ein Zusammenspiel von individuellen Problemen (z. B. Adipositas), gesellschaftlichen Herausforderungen (z. B. Klimaschutz) sowie veränderten Werthaltungen (z. B. Tierschutz). Die Ernährungspolitik hat auf diese Problemlagen lange Zeit wenig reagiert und die Verantwortung vornehmlich beim Individuum gesehen, es gibt wenig stützende Rahmenbedingungen. Vor diesem Hintergrund werden Forschungsergebnisse zum Ernährungshandeln der Verbraucher aufgezeigt und Instrumente der Ernährungspolitik diskutiert, die zu einer gesundheitsförderlichen Ernährung beitragen.
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This paper evaluates the effectiveness of restrictions on sugar‐sweetened beverages (SSBs) in schools as a policy approach aimed at reversing the upward trend in obesity among adolescents. Specifically, we test if the implementation of SB 965 in California high schools led to detectable compensation effects outside of school by estimating changes in soda purchases observed in store‐level scanner data. Our unique data and identification strategy address data limitations of previously published studies, and our reported results strengthen the notion that preferences for unhealthy foods will persist even after their availability is restricted in select environments. Related Content: Did the New School Meal Standards Improve the Overall Quality of Children's Diets? Related Content: Are College Students More Likely to Be Food Insecure than Nonstudents of Similar Ages? Related Content: School Meals and Quality of Household Food Acquisitions
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This chapter uses food behavior and food environments as the case gives an overview of some of the theoretical roots for the nudging approach and its underlying theoretical foundation often referred to as dual brain processes. It aims at critically assessing the approach for the case of food and nutrition behavior in relation to other policy options available. It attempts to locate the nudging approach into the landscape of environmentally focused interventions and the so-called choice architectures. It gives a brief account of recent evidence on the impact and effectiveness of such architectures in the context of food choice and ends up with a discussion of some of the ethical aspects of such types of interventions.
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Proper nutrition during infancy and early childhood is fundamental to the development of a healthy adult. Given the high nutrient demands of children, they are easily one of the population groups most susceptible to micronutrient deficiencies. Early weaning is one of the leading causes of child malnutrition and ultimately increases the risk of infant morbidity and mortality. After the first six months postpartum, breast milk becomes inadequate for the optimal growth and development of babies, and cereal-based foods are often introduced to increase nutrient intake and energy levels. Until children reach 3–5 years old their digestive systems are not yet fully developed and the food that is provided should thus contain all the nutrients necessary for a healthy development. Cereal-based foods are by far the major source of energy, protein, vitamins and minerals for infants from 6 to nearly 36 months old. This chapter deals principally with infant vitality and the importance of cereal foods for infant nutrition, the various types of cereal foods, the nutrients they contain, commercial infant cereals and cereal-based complementary foods for babies. Towards the end of the chapter, potential allergies and food safety parameters for these cereal foods are also discussed.
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Milk is the most important nutritional source for newborns and infants during the initial months of their lives. Breast milk is healthy for infants as it is easily digestible. Apart from its nutritional value, breast milk is known to have a positive impact on infants’ growth and development as it provides biochemical and immunological components including proteins, cytokines and hormones. Breast milk also decreases the risk of diarrhea, and morbidity from respiratory tract and urinary tract infections. In addition, breast feeding helps mothers to regain pre-pregnancy body weight and to return the uterus to its normal size and shape. In a few cases, however, breastfeeding is not possible due to conditions associated with the modern era such as malnutrition, the absence of the mother, insufficient lactation, food allergies and other maternal health issues. Because of these problems, infant milk formula may be preferred as an alternative, and is manufactured by industries to mimic the nutritional value of breast milk. Infant formulas, baby formulas or baby milk commonly use cow’s milk or soymilk as a base with added nutritional supplements. Nevertheless, infants fed with formula are at a higher risk from acute otitis media, asthma, type 1 and 2 diabetes, eczema, lower respiratory tract infections, sudden infant death syndrome (SIDS) and obesity. This article reviews human breast milk and problems associated with breast feeding, the need for infant formulas as an alternative form of nutrition, different types of infant formulas, the health benefits and risks of infant formulas, guidelines for the manufacture of infant formulas, and the global market.
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The positive impacts of prebiotics and probiotics on the gastrointestinal (GI) health of human adults have been known for many years. However, their effects on newborns and infants have not yet been analyzed in detail. Many processed baby foods are now enriched with probiotics, a live microbial food supplement that benefits the host by improving the microbial balance of the intestine. A more recent development has been the inclusion of prebiotics which has been observed to effectively promote the growth of specific gut microflora such as Bifidobacterium. However, a major issue encountered has been the survival of the organisms contained in the supplements both before ingestion, and afterwards on their way to the target organ, the gut. Synbiotics have been seen as a potential solution to this problem. Several studies have shown that probiotics and prebiotics can help to prevent infections in the GI tract of infants and also strengthen their immune system. This could make a huge difference to infants who have been bottle-fed and thus not provided with the probiotics they would normally have received from breast milk. This chapter describes the effects of pre- and probiotic supplements in detail, as well as their mechanisms of action, and also attempts to analyze their possible health benefits to infants.
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Lactose or milk sugar is a disaccharide composed of glucose and galactose, and is the primary carbohydrate found in mammalian milk. Lactose must be hydrolyzed into the simple sugars (galactose and glucose) to be absorbed by the small intestine. Lactase is an enzyme produced in the mucosa of the intestine that catalyzes the breakdown of lactose. Lactose intolerant children show low levels of lactase activity, and as a result, undigested lactose moves into the distal bowel. Here, symptoms such as bloating, cramps, diarrhea, flatulence and the production of gases occur in children (and lactose intolerant individuals’ in general) as the undigested lactose is fermented by bacteria. One of the health consequences of lactose intolerance (LI) in children is a reduction in calcium intake due to their avoidance of mammalian milk. Because of the problems associated with LI, many lactose-free food products are manufactured by the food industry. This chapter discusses LI in children, key symptoms of LI, methods to diagnose lactase insufficiency, lactase supplements, lactose-free food products and their health benefits and risks, and finally, the world market for these products and regulations and guidelines for industrial manufacturers.
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Carbohydrates, fats, proteins, minerals and vitamins are the main ingredients found in infant foods, and may be responsible for the symptoms of allergic reactions such as anaphylaxis, eczema, hives, mucus in stools, skin rash, etc. Cows’ milk (CM), soy, partially or fully hydrolyzed protein and amino acid-based formulas are the most common infant foods on the market. Sometimes, the protein present in CM generates intolerance in babies. Some of the supplements in soy formulas may also cause infant enterocolitis or proctocolitis. In soy formulas, whey or casein protein is pre-digested to provide nitrogen in the form of a mixture of amino acids and proteins. However, this hydrolysis process may lead to other unidentified allergic reactions, and therefore, does not make the formula non-allergenic. In this chapter, the nutritional composition of different infant foods and the allergic reactions they can provoke are described and discussed.
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The current epidemic of obesity is caused largely by an environment that promotes excessive food intake and discourages physical activity. Although humans have evolved excellent physiological mechanisms to defend against body weight loss, they have only weak physiological mechanisms to defend against body weight gain when food is abundant. Control of portion size, consumption of a diet low in fat and energy density, and regular physical activity are behaviors that protect against obesity, but it is becoming difficult to adopt and maintain these behaviors in the current environment. Because obesity is difficult to treat, public health efforts need to be directed toward prevention.
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Large portions of food may contribute to excess energy intake and greater obesity. However, data on the effects of portion size on food intake in adults are limited. We examined the effect of portion size on intake during a single meal. We also investigated whether the response to portion size depended on which person, the subject or the experimenter, determined the amount of food on the plate. Fifty-one men and women were served lunch 1 d/wk for 4 wk. Lunch included an entrée of macaroni and cheese consumed ad libitum. At each meal, subjects were presented with 1 of 4 portions of the entrée: 500, 625, 750, or 1000 g. One group of subjects received the portion on a plate, and a second group received it in a serving dish and took the amount they desired on their plates. Portion size significantly influenced energy intake at lunch (P < 0.0001). Subjects consumed 30% more energy (676 kJ) when offered the largest portion than when offered the smallest portion. The response to the variations in portion size was not influenced by who determined the amount of food on the plate or by subject characteristics such as sex, body mass index, or scores for dietary restraint or disinhibition. Larger portions led to greater energy intake regardless of serving method and subject characteristics. Portion size is a modifiable determinant of energy intake that should be addressed in connection with the prevention and treatment of obesity.
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Eating frequently in restaurants is one of the behaviors associated with obesity. This study examined whether increasing the portion size of an entrée affected energy intake at a restaurant meal. In a cafeteria-style restaurant on different days, the size of a pasta entrée was varied from a standard portion (248 g) to a large portion (377 g). The entrée price was not changed. Intake of the entrée was determined by covertly weighing each dish before and after the meal; intake of all other foods was determined by estimating the percent consumed. The 180 adult customers who purchased the entrée also completed a survey in which they rated characteristics of the meal, including the appropriateness of the entrée portion size and the amount that they ate compared with their usual meal. Portion size had a significant effect on intake of the entrée (p < 0.0001). Compared with customers who purchased the standard portion, those who purchased the larger portion increased their energy intake of the entrée by 43% (719 kJ; 172 kcal) and of the entire meal by 25% (664 kJ; 159 kcal). There was no difference between the two groups of customers in ratings of the appropriateness of the portion size or of the amount that was eaten in relation to their usual meal. In a restaurant setting, increasing the size of an entrée results in increased energy intake. These results support the suggestion that large restaurant portions may be contributing to the obesity epidemic.
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Increases in both the portion size and energy density of food have both been shown to increase energy intake, but the combined effects of such increases have not been investigated. The objective was to determine the combined effects of energy density and portion size on energy intake in women. This study used a within-subjects design. Once a week for 6 wk, 39 women were served breakfast, lunch, and dinner ad libitum. The main entrée at lunch was formulated in 2 versions that varied in energy density (5.23 or 7.32 kJ/g), each of which was served in 3 different portion sizes (500, 700, or 900 g). The 2 versions were matched for macronutrient composition and palatability. Breakfast and dinner were standard meals. Increases in portion size and energy density led to independent and additive increases in energy intake (P <0.0001). Subjects consumed 56% more energy (925 kJ) when served the largest portion of the higher energy-dense entrée than when served the smallest portion of the lower energy-dense entrée. Subjects did not compensate for the additional intake by eating less at the subsequent meal. Despite substantial differences in energy intake, no systematic differences in ratings of hunger and fullness across conditions were observed. The energy density and the portion size of a food act independently to affect energy intake. The findings indicate that large portions of foods with a high energy density may facilitate the overconsumption of energy.
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Package size, plate shape, lighting, socializing, and variety are only a few of the environmental factors that can influence the consumption volume of food far more than most people realize. Although such environmental factors appear unrelated, they generally influence consumption volume by inhibiting consumption monitoring and by suggesting alternative consumption norms. For researchers, this review suggests that redirecting the focus of investigations to the psychological mechanisms behind consumption will raise the profile and impact of research. For health professionals, this review underscores how small structural changes in personal environments can reduce the unknowing overconsumption of food.
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Using self-refilling soup bowls, this study examined whether visual cues related to portion size can influence intake volume without altering either estimated intake or satiation. Fifty-four participants (BMI, 17.3 to 36.0 kg/m2; 18 to 46 years of age) were recruited to participate in a study involving soup. The experiment was a between-subject design with two visibility levels: 1) an accurate visual cue of a food portion (normal bowl) vs. 2) a biased visual cue (self-refilling bowl). The soup apparatus was housed in a modified restaurant-style table in which two of four bowls slowly and imperceptibly refilled as their contents were consumed. Outcomes included intake volume, intake estimation, consumption monitoring, and satiety. Participants who were unknowingly eating from self-refilling bowls ate more soup [14.7+/-8.4 vs. 8.5+/-6.1 oz; F(1,52)=8.99; p<0.01] than those eating from normal soup bowls. However, despite consuming 73% more, they did not believe they had consumed more, nor did they perceive themselves as more sated than those eating from normal bowls. This was unaffected by BMI. These findings are consistent with the notion that the amount of food on a plate or bowl increases intake because it influences consumption norms and expectations and it lessens one's reliance on self-monitoring. It seems that people use their eyes to count calories and not their stomachs. The importance of having salient, accurate visual cues can play an important role in the prevention of unintentional overeating.
Article
Background: Increases in both the portion size and energy density of food have both been shown to increase energy intake, but the combined effects of such increases have not been investigated. Objective: The objective was to determine the combined effects of energy density and portion size on energy intake in women. Design: This study used a within-subjects design. Once a week for 6 wk, 39 women were served breakfast, lunch, and dinner ad libitum. The main entrée at lunch was formulated in 2 versions that varied in energy density (5.23 or 7.32 kJ/g), each of which was served in 3 different portion sizes (500, 700, or 900 g). The 2 versions were matched for macronutrient composition and palatability. Breakfast and dinner were standard meals. Results: Increases in portion size and energy density led to independent and additive increases in energy intake (P <0.0001). Subjects consumed 56% more energy (925 kJ) when served the largest portion of the higher energy-dense entrée than when served the smallest portion of the lower energy-dense entrée. Subjects did not compensate for the additional intake by eating less at the subsequent meal. Despite substantial differences in energy intake, no systematic differences in ratings of hunger and fullness across conditions were observed. Conclusions: The energy density and the portion size of a food act independently to affect energy intake. The findings indicate that large portions of foods with a high energy density may facilitate the overconsumption of energy.
Article
Although we are just beginning to understand how environmental factors such as portion size affect eating behavior, the available data suggest that large portions of energy-dense foods are contributing to the obesity epidemic. Several possible strategies for adjusting portions to bring intake back in line with energy requirements are discussed. The continuing rise in the rates of obesity calls for urgent action.
Article
Although we are just beginning to understand how environmental factors such as portion size affect eating behavior, the available data suggest that large portions of energy-dense foods are contributing to the obesity epidemic. Several possible strategies for adjusting portions to bring intake back in line with energy requirements are discussed. The continuing rise in the rates of obesity calls for urgent action.
Article
Part of the "French paradox" can be explained by the fact that the French eat less than Americans. We document that French portion sizes are smaller in comparable restaurants, in the sizes of individual portions of foods (but not other items) in supermarkets, in portions specified in cookbooks, and in the prominence of "all you can eat" restaurants in dining guides. We also present data, from observations at McDonald's, that the French take longer to eat than Americans. Our results suggest that in the domain of eating, and more generally, more attention should be paid to ecological factors, even though their mechanism of operation is transparent, and hence less revealing of fundamental psychological processes. Ironically, although the French eat less than Americans, they seem to eat for a longer period of time, and hence have more food experience. The French can have their cake and eat it as well.
Increased portion size leads to increased energy intake in a res-taurant meal The psychology of overeating Food, diet, and obesity Environmental contributions to the obesity epidemic
  • C P Herman
  • J Polivy
  • T Leone
Increased portion size leads to increased energy intake in a res-taurant meal. Obesity Research, 12, 562–568. Herman, C.P., Polivy, J., & Leone, T. (in press). The psychology of overeating. In D. Mela (Ed.), Food, diet, and obesity. Cambridge, England: Woodhead Publishing. Hill, J.O., & Peters, J.C. (1998). Environmental contributions to the obesity epidemic. Science, 280, 1371–1374
The ecology of eating: Part of the French paradox results from lower
  • P Rozin
  • K Kabnick
  • E Pete
  • C Fischler
  • C Shields
Rozin, P., Kabnick, K., Pete, E., Fischler, C., & Shields, C. (2003). The ecology of eating: Part of the French paradox results from lower Volume 17—Number 6