Testing an online measure of portion size selection: a pilot study concerned with the measurement of ideal portion size

Background Portion size is known to be a key driver of food intake. As consumed portions are often pre-planned, ‘ideal portion size’—an individual’s preferred meal size selected prior to eating—has been identified as a strong predictor of actual consumption. However, assessments of ideal portion size have predominantly relied on laboratory-based computer tasks, limiting use online. Therefore, this cross-sectional study sought to pilot test the validity of a web-based tool to measure ideal portion size. Methods In an online study (N = 48), participants responded to images of a range of foods. Each food was photographed in a series of different portions and loaded into an ‘image carousel’ that would allow participants to change the size of the displayed portion by moving a slider left-to-right. Using this image carousel, participants selected their ideal portion size. They also completed measures of expected satiety and expected satiation and self-reported their age and body mass index (BMI). A non-parametric correlation matrix was used to explore associations between ideal portion size and identified predictors of food intake. Results Supporting convergent validity of this measure, ideal portion size was significantly correlated with expected satiety (rs = .480) and expected satiation (rs = −.310) after controlling for effects of baseline hunger and fullness, consistent with past research. Similarly, supporting divergent validity of this measure, ideal portion size was not significantly correlated with age (rs = −.032) or BMI (rs = −.111,). Conclusions Pilot results support the validity of this web-based portion size selection tool used to measure ideal portion size, though further research is needed to validate use with comparisons to actual food intake.

Food Purchases in an Online Virtual Restaurant

Objectives Food is commonly purchased at fast-food restaurants and improving food choices at these establishments may be a key contributor to improving the nation's diet. A better understanding of the barriers to dietary change when purchasing foods at fast-food restaurants may aid the development of new interventions to improve dietary choices. The objective of this study is to determine the costs and benefits of choosing a lower calorie meal in a 3D virtual representation of a fast-food restaurant. Methods In this ongoing study, a 3D model of a fast-food restaurant was created and accessed by participants through the internet. The foods on the menu, their nutritional content and price were based on foods served at popular fast-food restaurants. After completing a demographic questionnaire, participants were placed at the entrance of a 3D virtual restaurant where the rated their subjective appetite and rated the expected palatability and satiety of the foods on the menu. Participants were then randomized to one of two conditions: free-choice or goal-orientated (asked to choose a meal that was 700kcal). The participant could then view all menu items on a representation of an electronic ordering kiosk in the store and was asked to ‘purchase’ a meal. After the meal was selected, participants were asked to rate the palatability and expected satiety of that meal. The cost and nutritional content of the meal was determined. Results Preliminary data are presented but as the study is in progress statistical analysis has not currently been performed. Twenty-three participants have currently completed the study. The energy purchased in the free condition is 941kcal while in the constrained condition it is 722 kcal. The cost of the constrained meal is $6.93 and the free meal is $7.16. People in the free condition have taken 65.2 seconds to order whereas people in the constrained condition have taken 72.3 seconds. Conclusions This ongoing study illustrated the potential for collecting data about food choices using virtual worlds. This approach may provide new insights into how people make food decisions. Funding Sources This project received no funding.

Fat and Carbohydrate Interact to Potentiate Food Reward in Healthy Weight but Not in Overweight or Obesity

Prior work suggests that actual, but not estimated, energy density drives the reinforcing value of food and that energy from fat and carbohydrate can interact to potentiate reward. Here we sought to replicate these findings in an American sample and to determine if the effects are influenced by body mass index (BMI). Thirty participants with healthy weight (HW; BMI 21.92 ± 1.77; M ± SD) and 30 participants with overweight/obesity (OW/OB; BMI 29.42 ± 4.44) rated pictures of common American snacks in 120-kcal portions for liking, familiarity, frequency of consumption, expected satiety, healthiness, energy content, energy density, and price. Participants then completed an auction task where they bid for the opportunity to consume each food. Snacks contained either primarily carbohydrate, primarily fat, or roughly equal portions of fat and carbohydrate (combo). Replicating prior work, we found that participants with HW bid the most for combo foods in linear mixed model analyses. This effect was not observed among individuals with OW/OB. Additionally, in contrast with previous reports, our linear regression analyses revealed a negative relationship between the actual energy density of the snacks and bid amount that was mediated by food price. Our findings support altered macronutrient reinforcement in obesity and highlight potential influences of the food environment on the regulation of food reward.

Testing an online measure of ideal portion size: A pilot study

Portion size is known to be a key driver of food intake. As consumed portions are often pre-planned, ‘ideal portion size’ – an individual’s preferred meal size selected prior to eating – has been identified as a strong predictor of actual consumption. However, assessments of ideal portion size have predominantly relied on laboratory-based computer tasks, limiting use online. Therefore, this study sought to pilot test the validity of a web-based tool to measure ideal portion size. In an online study (N = 48), participants responded to images of a range of foods. Each food was photographed in a series of different portions, and loaded into an ‘image carousel’ that would allow participants to change the size of the displayed portion by moving a slider left-to-right. Using this image carousel, participants selected their ideal portion size. They also completed measures of expected satiety and expected satiation, and self-reported their age and body mass index (BMI). A non-parametric correlation matrix was used to explore associations between ideal portion size and identified predictors of food intake. Supporting convergent validity of this measure, ideal portion size was significantly correlated with expected satiety and expected satiation (after controlling for effects of baseline hunger and fullness), consistent with past research. Similarly, supporting divergent validity of this measure, ideal portion size was not significantly correlated with age or BMI. Pilot results support the validity of this web-based tool to measure ideal portion size, though further research is needed to validate use with comparisons to actual food intake.

Fat and carbohydrate interact to potentiate food reward in healthy weight but not in overweight or obesity

Prior work suggests that actual, but not estimated, energy density drives the reinforcing value of food [1,2] and that energy from fat and carbohydrate can interact to potentiate reward [2]. Here we sought to replicate these findings in an American sample and to determine if the effects are influenced by body mass index (BMI). Thirty participants with healthy weight (HW; BMI 21.92 ± 1.77; M ± SD) and 30 participants with overweight/obesity (OW/OB; BMI 29.42 ± 4.44) rated pictures of common American snacks in 120-kcal portions for liking, familiarity, frequency of consumption, expected satiety, healthiness, energy content, energy density, and price. Participants then completed an auction task where they bid for the opportunity to consume each food. Snacks contained either primarily carbohydrate, primarily fat, or roughly equal portions of fat and carbohydrate (combo). Replicating prior work, we found that participants with HW bid the most for combo foods in linear mixed model analyses. This effect was not observed among individuals with OW/OB. Additionally, in contrast with previous reports [1,2], our linear regression analyses revealed a negative relationship between the actual energy density of the snacks and bid amount that was mediated by food price. Our findings support altered macronutrient reinforcement in obesity and highlight potential influences of the food environment on the regulation of food reward.

Experience of Using an Online Pre-Ordering System for A Workplace Canteen That Offers Lower-Energy Swaps: A Think-Aloud Study

Online systems that allow employees to pre-order their lunch may help reduce energy intake. We investigated the acceptability of a pre-ordering website for a workplace canteen that prompts customers to swap to lower-energy swaps and the factors influencing swap acceptance. Employees (n = 30) placed a hypothetical lunch order through a pre-ordering website designed for their canteen while thinking aloud. Semi-structured interview questions supported data collection. Data were analysed using thematic analysis. Acceptability was generally high, but potentially context dependent. Practical considerations, such as reminders to pre-order, user-friendliness, provision of images of menu items and energy information while browsing, an ability to reserve pre-ordered meals, and a swift collection service facilitated acceptability. The restrictive timeframe within which orders could be placed, a lack of opportunity to see foods before ordering, and prompts to swap being perceived as threatening autonomy were barriers to acceptability. Swap acceptance was facilitated by the provision of physical activity calorie equivalents (PACE) information, and swap similarity in terms of taste, texture, and expected satiety as well as the perception that alternatives provided meaningful energy savings. Online canteen pre-ordering systems that prompt lower-energy swaps may be an acceptable approach to help reduce energy intake in the workplace.

Do Consumers Change Their Perception of Liking, Expected Satiety, and Healthiness of a Product If They Know It Is a Ready-to Eat Meal?

A ready-to-eat meal is a prepared meal within a container or package that requires little preparation or heating before consumption. Despite ready-to-eat meals being widely consumed, to date, little information is available on the consumers’ perceptions of such products in comparison to a homemade meal. Thus, three groups of eighty participants took part in the present study; each group evaluated five ready-to-eat meals (Pasta, Meatballs, Salad, Beans, and a Sandwich) using one of the following conditions: (i) observation of the packaging, (ii) observation of the meal on a plate (photographs), and (iii) tasting the ready-to-eat product with the packaging being presented alongside the meal. Consumers were asked about their liking, satiety, and healthiness perception. The results showed that both the ready-to-eat pack and sensory quality of the product highly impact liking and healthiness perceptions. Being a ready-to-eat meal in a pack has a negative impact on liking expectations of the meal; however, the sensory quality can either counteract these effects or increase them. Expected satiety of meals depends on the type of meal and varies slightly according to the evaluation condition.