Served Portion Sizes Affect Later Food Intake Through Social Consumption Norms.
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ABSTRACT:
SUBMITTER: Raghoebar S
PROVIDER: S-EPMC6949930 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:BACKGROUND: Environmental interventions directed at portion size might help consumers to reduce their food intake. OBJECTIVE: To assess whether offering a smaller hot meal, in addition to the existing size, stimulates people to replace their large meal with a smaller meal. DESIGN: Longitudinal randomized controlled trial assessing the impact of introducing small portion sizes and pricing strategies on consumer choices. SETTING/PARTICIPANTS: In all, 25 worksite cafeterias and a panel consisting of 308 consumers (mean age=39.18 years, 50% women). INTERVENTION: A small portion size of hot meals was offered in addition to the existing size. The meals were either proportionally priced (that is, the price per gram was comparable regardless of the size) or value size pricing was employed. MAIN OUTCOME MEASURES: Daily sales of small and the total number of meals, consumers' self-reported compensation behavior and frequency of purchasing small meals. RESULTS: The ratio of small meals sales in relation to large meals sales was 10.2%. No effect of proportional pricing was found B=-0.11 (0.33), P=0.74, confidence interval (CI): -0.76 to 0.54). The consumer data indicated that 19.5% of the participants who had selected a small meal often-to-always purchased more products than usual in the worksite cafeteria. Small meal purchases were negatively related to being male (B=-0.85 (0.20), P=0.00, CI: -1.24 to -0.46, n=178). CONCLUSION: When offering a small meal in addition to the existing size, a percentage of consumers that is considered reasonable were inclined to replace the large meal with the small meal. Proportional prices did not have an additional effect. The possible occurrence of compensation behavior is an issue that merits further attention.
| S-EPMC3172584 | biostudies-other
Project description:People typically eat more from large portions of food than from small portions. An explanation that has often been given for this so-called portion size effect is that the portion size acts as a social norm and as such communicates how much is appropriate to eat. In this paper, we tested this explanation by examining whether manipulating the relevance of the portion size as a social norm changes the portion size effect, as assessed by prospective consumption decisions. We conducted one pilot experiment and one full experiment in which participants respectively indicated how much they would eat or serve themselves from a given amount of different foods. In the pilot (N = 63), we manipulated normative relevance by allegedly basing the portion size on the behavior of either students of the own university (in-group) or of another university (out-group). In the main experiment (N = 321), we told participants that either a minority or majority of people similar to them approved of the portion size. Results show that in both experiments, participants expected to serve themselves and to eat more from larger than from smaller portions. As expected, however, the portion size effect was less pronounced when the reference portions were allegedly based on the behavior of an out-group (pilot) or approved only by a minority (main experiment). These findings suggest that the portion size indeed provides normative information, because participants were less influenced by it if it communicated the behaviors or values of a less relevant social group. In addition, in the main experiment, the relation between portion size and the expected amount served was partially mediated by the amount that was considered appropriate, suggesting that concerns about eating an appropriate amount indeed play a role in the portion size effect. However, since the portion size effect was weakened but not eliminated by the normative relevance manipulations and since mediation was only partial, other mechanisms may also play a role.
| S-EPMC4885850 | biostudies-literature
Project description:BACKGROUND:The association between the residential fast food environment and diet has gained growing attention. However, why the food environment affects food consumption is under-examined. This study aimed to investigate neighbourhood social norms with respect to fast food consumption as a potential mediating pathway between residential fast food outlet exposure and residents' fast food consumption. METHODS:A correlational study was conducted in which a nationwide sample of 1038 respondents living across The Netherlands completed a survey. Respondents reported their fast food consumption (amount/week) as well as perceived descriptive and injunctive norms regarding fast food consumption in their neighbourhood. Fast food outlet exposure was measured by the average count of fast food outlets within a 400?m walking distance buffer around the zip-codes of the respondents, using a retail outlet database. Regression models were used to assess associations between residential fast food outlet exposure, fast food consumption, and social norm perceptions, and a bootstrapping procedure was used to test the indirect -mediation- effect. Separate analyses were performed for descriptive norms and injunctive norms. RESULTS:There was no overall or direct association between residential fast food outlet exposure and residents' fast food consumption. However, fast food outlet exposure was positively associated with neighbourhood social norms (descriptive and injunctive) regarding fast food consumption, which in turn were positively associated with the odds of consuming fast food. Moreover, results of the bootstrapped analysis provided evidence of indirect effects of fast food outlet exposure on fast food consumption, via descriptive norms and injunctive norms. CONCLUSIONS:In neighbourhoods with more fast food outlets, residents were more likely to perceive fast food consumption in the neighbourhood as more common and appropriate. In turn, stronger neighbourhood social norms were associated with higher fast food consumption. Acknowledging the correlational design, this study is the first that implies that neighbourhood social norms may be a mediating pathway in the relation between the residential fast food environment and fast food consumption. Future research may examine the role of neighbourhood social norms in other contexts and explore how the changing food environment may shift our consumption norms.
| S-EPMC7218623 | biostudies-literature
Project description:BackgroundInaccurate self-report of portion sizes is a major cause of measurement error in dietary assessment. To reduce this error, different portion size estimation aids (PSEAs) have been developed, including food images (image based, IB-PSE) and textual descriptions of portion sizes (text-based, TB-PSE). We assessed the accuracy of portion size estimation by IB-PSE and TB-PSE.MethodsTrue intake of one lunch was ascertained in forty participants. Self-reported portion sizes were assessed after 2 and 24 hours by means of TB-PSE and IB-PSE, in random order. Wilcoxon's tests were used to compare mean true intakes to reported intakes. Moreover, proportions of reported portion sizes within 10% and 25% of true intake were assessed. An adapted Bland-Altman approach was used to assess agreement between true and reported portion sizes. Analyses were conducted for all foods and drinks combined and for predetermined food types.ResultsNo significant differences were observed between reported portion sizes at 2 and 24 hours after lunch. Combining median relative errors of all foods items resulted in an overall 0% error rate for TB-PSE and 6% error rate for IB-PSE. Comparing reported portion sizes within 10% (31% vs. 13%) and 25% (50% vs. 35%) of the true intake showed a better performance for TB-PSE compared to IP-PSE, respectively. Bland-Altman plots indicated a higher agreement between reported and true intake for TB-PSE compared to IB-PSE.ConclusionsAlthough the use of TB-PSE still results in measurement error, our results suggest a more accurate dietary intake assessment with TB-PSE than IB-PSE.
| S-EPMC9291996 | biostudies-literature
Project description:We evaluated whether novel portion size and consistency indicators can identify children with low complementary food energy intake in southern Ethiopia. We conducted 24-h dietary recalls with caregivers of 548 children aged 6-13 months; additionally, caregivers estimated their child's usual portion size using uncooked rice and selected which of five photographs of porridges of varying consistencies most closely matched the food their child usually ate. Complementary food energy and density from the 24-h recall were used as reference values. We computed correlation coefficients and areas under receiver operating characteristic curves (AUC) and conducted sensitivity and specificity analyses to classify children with low complementary food energy intake. The median complementary food energy intakes for children 6-8, 9-11 and 12-13 months were 312, 322 and 375 kcal; median estimated portion sizes were 50, 58 and 64 ml, respectively. Estimated portion size correlated with total complementary food energy intake and with average energy and quantity consumed per feeding (r = 0.42, 0.46 and 0.45, respectively, all p < 0.001). Reported food consistency was weakly correlated with total complementary food energy intake (r = 0.18) and density (r = 0.10), and energy density of porridge only (r = 0.24, all p < 0.05). Predicted energy intake combining feeding frequency and portion size predicted inadequate energy intake better than did feeding frequency alone in infants 6-8 months [∆AUC = 0.16, 95% confidence interval (CI) 0.04, 0.28] and 9-11 months (∆AUC = 0.09, 95% CI 0.04, 0.14). Caregiver estimates of portion size can improve identification of infants with low complementary food energy intake when more robust dietary assessment is not feasible.
| S-EPMC7988842 | biostudies-literature
Project description:Validated methodological aids for food quantification are needed for the accurate estimation of food consumption. Our objective was to assess the validity of an age-specific food picture book, which contains commonly eaten foods among Finnish children, for parents and early educators in estimating food portion sizes. The food picture book was developed to assist in portion size estimation when filling in food records in the Increased health and wellbeing in preschools (DAGIS) study. All ninety-five food pictures in the book, each containing three or four different portion sizes, were evaluated at real-time sessions. Altogether, seventy-three parents and 107 early educators or early education students participated. Each participant evaluated twenty-three or twenty-four portions by comparing presented pre-weighed food portions against the corresponding picture from the food picture book. Food portions were not consumed by participants. The total proportion of correct estimations varied from 36 % (cottage cheese) to 100 % (fish fingers). Among the food groups, nearly or over 90 % of the estimations were correct for bread, pastries and main courses ('piece products' such as meatballs and chicken nuggets). Soups, porridges, salads and grated and fresh vegetables were least correctly estimated (<65 % correct estimations). There were small differences in evaluations of berries and fresh fruits, warm vegetables and pastries between the parents and early educators, but other estimations were mostly similar. The children's food picture book was found to be a useful aid for the estimation of food portion sizes. Parents and early educators evaluated the portion sizes with similar accuracy.
| S-EPMC6313402 | biostudies-literature
Project description:BackgroundSmaller portions may help to reduce energy intake. However, there may be a limit to the magnitude of the portion size reduction that can be made before consumers respond by increasing intake of other food immediately or at later meals. We tested the theoretical prediction that reductions to portion size would result in a significant reduction to daily energy intake when the resulting portion was visually perceived as 'normal' in size, but that a reduction resulting in a 'smaller than normal' portion size would cause immediate or later additional eating.MethodsOver three 5-day periods, daily energy intake was measured in a controlled laboratory study using a randomized crossover design (N = 30). The served portion size of the main meal component of lunch and dinner was manipulated in three conditions: 'large-normal' (747 kcal), 'small-normal' (543 kcal), and 'smaller than normal' (339 kcal). Perceived 'normality' of portion sizes was determined by two pilot studies. Ad libitum daily energy intake from all meals and snacks was measured.ResultsDaily energy intake in the 'large-normal' condition was 2543 kcals. Daily energy intake was significantly lower in the 'small-normal' portion size condition (mean difference - 95 kcal/d, 95% CI [- 184, - 6], p = .04); and was also significantly lower in the 'smaller than normal' than the 'small-normal' condition (mean difference - 210 kcal/d, 95% CI [- 309, - 111], p < .001). Contrary to predictions, there was no evidence that the degree of additional food consumption observed was greater when portions were reduced past the point of appearing normal in size.ConclusionsReductions to the portion size of main-meal foods resulted in significant decreases in daily energy intake. Additional food consumption did not offset this effect, even when portions were reduced to the point that they were no longer perceived as being normal in size.Trial registrationProspectively registered protocol and analysis plan: https://osf.io/natws/; retrospectively registered: https://clinicaltrials.gov/ct2/show/NCT03811210.
| S-EPMC7017560 | biostudies-literature
Project description:Accurate and easy-to-understand nutrition labeling is a worthy public health goal that should be considered an important strategy among many to address obesity and poor diet. Updating the Nutrition Facts Panel on packaged foods, developing a uniform front-of-package labeling system and providing consumers with nutrition information on restaurant menus offer important opportunities to educate people about food's nutritional content, increase awareness of reasonable portion sizes and motivate consumers to make healthier choices. The aims of this paper were to identify and discuss: (1) current concerns with nutrition label communication strategies; (2) opportunities to improve the communication of nutrition information via food labels, with a specific focus on serving size information; and (3) important future areas of research on nutrition labeling as a tool to improve diet. We suggest that research on nutrition labeling should focus on ways to improve food labels' ability to capture consumer attention, reduce label complexity and convey numeric nutrition information in simpler and more meaningful ways, such as through interpretive food labels, the addition of simple text, reduced use of percentages and easy-to-understand presentation of serving size information.
| S-EPMC4105581 | biostudies-other
Project description:ObjectiveAdolescents and young adults select larger portions of energy-dense food than recommended. The majority of young people have a social media profile, and peer influence on social media may moderate the size of portions selected.MethodsTwo pilot interventions examined whether exposure to images of peers' portions of high-energy-dense (HED) snacks and sugar-sweetened beverages (SSBs) on social media (Instagram) would influence reported desired portions selected on a survey. Confederate peers posted 'their' portions of HED snacks and SSBs on Instagram. At baseline and intervention end participants completed surveys that assessed desired portion sizes.ResultsIn intervention 1, undergraduate students (n = 20, mean age=19.0 years, SD=0.65) participated in a two-week intervention in a within-subjects design. Participants reported smaller desired portions of HED snacks and SSBs following the intervention, and smaller desired portions of HED snacks for their peers. In intervention 2, adolescents (n = 44, mean age = 14.4 years, SD = 1.06) participated in a four-week intervention (n = 23) or control condition (n = 21) in a between-subjects design. Intervention 2 did not influence adolescents to reduce their reported desired portion sizes of HED snacks or SSBs relative to control.ConclusionsThese preliminary studies demonstrated that social media is a feasible way to communicate with young people. However, while the intervention influenced young adults' reported desired portions and social norms regarding their peers' portions, no significant impact on desired reported portion sizes was found for HED snacks and SSBs in adolescents. Desired portion sizes of some foods and beverages may be resistant to change via a social media intervention in this age group.
| S-EPMC6757490 | biostudies-literature
Project description:BackgroundPortion size of foods is reported to contribute to the rise in obesity prevalence. However, evidence of changes in portion size for commonly consumed foods in Australia is lacking. The aim was to evaluate whether Australian child and adolescent portion sizes of selected foods changed from 1995 to 2007.MethodsTime-series study, comparing dietary data from two national cross-sectional surveys in nationally representative population survey of Australian households. The dietary data was from children aged 2-16 years who participated in the 1995 National Nutrition Survey (n?=?2198) and 2007 Australian National Children's Nutrition and Physical Activity Survey (n?=?4799).ResultsDifferences were found across survey years in median portion size of common foods and beverages assessed by 24-hour recalls for age and sex categories. Of the 61 foods items evaluated across the whole population sample, portion size increased in 18 items, decreased in 22, with no change in 20, although the magnitude of change varied by age and sex. Decreases in portion size were detected for most dairy products, breakfast cereal, some packaged snack foods and vegetables, p?<?0.0001. Increases were detected for cooked chicken, mixed chicken dishes, bacon and ham (p?<?0.0001), cooked meat (p?<?0.05), fish (p?<?0.01) and pizza (p?<?0.0001). No significant changes were detected for many items including white and wholemeal bread, mincemeat, chocolate and soft drink.ConclusionsSmall changes in portion sizes were detected over 12 years in Australian children and adolescents with the degree of change varying by sex, age and food group. Knowledge of usual portion sizes could inform programs targeting appropriate serving sizes selection in children and adolescents.
| S-EPMC4061520 | biostudies-literature