Computer-based assessments of expected satiety predict behavioural measures of portion-size selection and food intake

Breadth of substance use is associated with the selection of a larger food portion size via elevated impulsivity

Substance use is associated with altered or elevated food consumption and disordered eating. In the present study we examined whether breadth (variety) of drug use was associated with elevated portion size in a general population sample as it was in persons in recovery from substance use disorder. Furthermore, measures of emotional eating, impulsivity, food misuse, food craving were taken as possible mediators and reward responsiveness was examined as a potential moderator of this association. 444 adults (48.6 % women, mean age of 47.8 years) completed an online study in which they were asked to make judgements of ideal portion size for 6 different foods using a validated online tool that allowed participants to adjust the portion size of images of foods. Ideal portion size has been identified as a strong predictor of actual consumption. Participants were also asked to report the number of substances used in the past and provide anthropometric information. The results confirmed that breadth of drug use was associated with selection of higher portion size. Reward responsiveness was not a moderator of this relationship. Of the tested mediators, only impulsivity mediated the association between breadth of drug use and portion size. The results show that impulsivity may underlie the association between eating and substance use.

Inhibitory control mediates the effect of high intensity interval exercise on food choice

Exercise is associated with changes in food consumption and cognitive function. The aim of this study was to examine the immediate effects of acute exercise on appetite, food choices, and cognitive processes, and the mediating role of cognitive functioning, namely inhibitory control, working memory, cognitive flexibility and decision making. We compared the effects of high-intensity interval exercise (HIIE) to a resting condition on appetite and food choices, using visual analogue rating scales and a computerised portion selection task. Mediation analysis was performed with exercise/rest condition as a predictor variable and cognitive measures were entered as mediating variables and food choice measures as outcomes. Young women with low activity levels, aged between 18 and 35 years with a body mass index (BMI) between 18 and 25 kg/m², were recruited. Participants (n = 30) demonstrated improved performance on a Stroop task following HIIE compared to the rest session, indicating enhanced attentional inhibition. Accuracy on an N-back task was significantly higher after HIIE, indicating an improvement in working memory and response times on the N-back task were shorter after HIIE, suggesting increased processing speed. Delay discounting for food (but not money) was reduced after HIEE but there were no significant effects on go/no-go task performance. On the trail-making task (a measure of cognitive flexibility), the time difference between trail B and A was significantly lower after HIIE, compared to rest. HIIE reduced rated enjoyment and ideal portion size selection for high energy dense foods. The relationship between exercise and food choices was mediated by inhibition as assessed by the Stoop task. These results suggest that HIIE leads to cognitive benefits and a reduced preference for high-calorie foods and that an enhancement of attentional inhibition may underlie this relationship.

Exploring within-meal variety to promote appeal of home-cooked meals in older adults

Undernutrition is highly prevalent in older adults and poses a major threat to physical and mental wellbeing. To foster healthy eating (and healthy aging), strategies are needed to improve dietary quality of older adults. In this study, the feasibility of increasing food variety in home-cooked meals is explored as strategy to promote meat and vegetable consumption in community dwelling older adults. Adults aged 50 years or older (N = 253) evaluated pictures of traditional Dutch dinner meals with more or less variety in the vegetable or meat component in an online questionnaire. Specifically, four different variety 'levels' were presented: (1) no variety, (2) meat variety, (3) vegetable variety, and (4) variety in both meat and vegetables (mixed). Participants indicated for each meal picture how much they would like the meal, whether it represented an ideal portion size, and whether they would be able and willing to prepare the meal. We expected that with increasing variety, liking and ideal portion size would increase, while ability and willingness to prepare the meals would decrease. Results showed that the meals with meat variety and mixed variety were liked less than meals with vegetable variety or no variety. Participants were all highly willing to prepare the meals, but they were less willing to prepare the meals with meat variety and mixed variety compared to the meals with vegetable variety and no variety. All meals were evaluated as being too large, but the meals with vegetable variety and mixed variety were evaluated as more oversized than the meals without variety and with meat variety. These results suggest that encouraging older adults to include variety in home-cooked meals might be more challenging than anticipated.

Development of Momentary Appetite Capture (MAC): A versatile tool for monitoring appetite over long periods

Understanding how an intervention impacts appetite in real-life settings and over several days remains a challenging and under-explored research question. To this end, we developed Momentary Appetite Capture (MAC), a form of ecological momentary assessment that combines automated text messaging with an online platform. Participants report their appetite using visual analogue scales (hunger, desire to eat, and fullness) and a virtual portion-size selection task. In two separate studies, we assessed the feasibility and test-retest reliability of MAC. Participants were prompted every 2 hours over a 14-hour window, and they repeated this assessment over two consecutive weekdays. For each participant, we calculated a daily time-averaged area under the curve (AUC) for each appetite measure. In Study One (N = 25) time-averaged AUC was significantly positively correlated across test days for hunger (r = 0.563, p = .003), desire to eat (r = 0.515, p = .008) and prospective portion size (r = 0.914, p < .001), but not for fullness (r = 0.342, p = .094). Participants completed 95% of MACs (380 of 400), and we used participant feedback to improve the MAC tool and study protocol for Study Two. In Study Two (N = 31), 94% of MACs were completed (468 of 496). Across days, time-averaged AUC was significantly positively correlated for hunger (r = 0.595, p = < .001), fullness (r = 0.501, p = .004), desire to eat (r = 0.585, p < .001), and prospective portion size (r = 0.757, p < .001). Together, these studies suggest that MAC could be an acceptable and reliable tool to track appetite throughout the day. In the future, MAC could be used to explore the impact of weight-loss interventions on natural fluctuations in appetite.

Food selection in a buffet scenario by persons in recovery from substance use disorder: Testing a parallel mediation model including impulsivity, food craving, and breadth of drug use

Elevated food cravings and higher food consumption and body weight have been reported in studies of people in recovery from substance use disorder (SUD). In a previous study, SUD recovery status predicted the energy from selected food images in a virtual buffet meal, most strongly in those with high reward responsiveness. The present study was conducted to determine which psychological variables might mediate the relationship between SUD recovery status and food selection and to replicate the finding that reward responsiveness moderated this relationship. In an online study, 216 women and men (109 in recovery from SUD) were asked to choose from among 16 food images in an all-you-can-eat buffet scenario. Food craving, impulsivity, "food addiction", irrational food beliefs, anhedonia, and breadth of drug use were examined as potential mediators while reward responsiveness was examined as a potential moderator. The amount of energy in the selected foods was the outcome variable. Results indicated that breadth of drug use was a mediator; being in SUD recovery predicted higher variety of drug use which predicted higher food selection. However, reward responsiveness did not moderate the relationship between SUD recovery status and energy from the selected foods. Exploratory analysis indicated that lack of premeditation, a measure of impulsivity, with food craving partially mediated the relationship between breadth of drug use and energy from selected foods and that lack of premeditation fully mediated it for sweet foods. The results confirm an association between substance use and food selection and suggest a mechanism via impulsivity.

Does social-norm messaging influence expected satiety and ideal portion-size selection?

A person's perception of how long a food will stave off hunger (expected satiety) and the ideal amount to consume (ideal portion size) are both influenced by food-to-mealtime norms. Here, we examine whether social norms can modulate this effect, in three experimental studies. In study 1 (n = 235) participants were exposed to a social norm suggesting most people enjoyed consuming pasta for breakfast. There was a main effect of food-to-mealtime congruence for expected satiety and ideal portion size (p < 0.001) - participants selected a smaller portion of pasta for breakfast (vs. lunch) - but there were no other main effects/interactions (p ≥ 0.15). Study 2 (n = 200) followed the same approach as study 1, but sought to examine whether the typical volume of food consumed at breakfast and lunch needed to be controlled. Again, there was a main effect of congruence (the same pattern) (p ≤ 0.02) but no other main effects/interactions (p ≥ 0.73). Study 3 (n = 208) followed the same approach as study 2, but the social-norm message was changed to suggest that most people who eat pasta for breakfast found it effectively reduced their hunger. Again, there was a main effect of congruence (the same pattern) (p < 0.001) but no other main effects/interaction (p ≥ 0.26). These studies provide further evidence for the food-to-mealtime effect, but do not provide any evidence that a single, simple social-norm statement can modulate expected satiety or ideal portion size, or interact with the food-to-mealtime effect.

Effects of cueing multiple memories of eating on people's judgments about their diet

Past research shows that recalling a single positive health-related experience, such as exercising, can encourage people's subsequent healthy behaviours. In contrast, we reasoned that attempting to recall many healthy experiences might elicit a metacognitive experience of difficulty that would lead people to perceive themselves as less healthy, and perhaps to make other health-related judgments based on this perception. In two pre-registered experiments (combined N = 729), participants recalled either "few" or "many" instances of eating either healthily or unhealthily, before rating the healthiness of their diets and completing measures of their eating preferences and choices. Contrary to our predictions, our pre-registered analyses provided minimal evidence that the number of memories people retrieved affected their judgments. However, exploratory mediation analyses suggested that two counteracting effects may have occurred, whereby retrieving more (un)healthy memories led people to identify as more (un)healthy, yet also created a sense of subjective difficulty that partially or wholly negated these effects. These findings suggest that whereas probing people's dietary memories might sometimes lead to healthier self-perceptions and dietary choices, we should also consider the possibility of backfire effects.

Perceived inequality in society may not motivate increased food intake in the absence of personal socioeconomic disadvantage

BACKGROUND

Greater levels of socioeconomic inequality across societies have been associated with higher rates of obesity and cardiometabolic disease. While these relationships could be attributed to poorer quality of health services and lower access to healthier lifestyles among disadvantaged groups in societies with greater economic inequality, this explanation does not account for those who experience relative economic security in such unequal societies (e.g., the middle and upper classes). Here, we tested whether perceptions of greater disparities between social classes in one's society (i.e., perceived societal inequality) may promote eating behaviors that risk excess energy intake.

METHODS

In two studies, participants completed an experimental manipulation that situated them as middle class within a hypothetical society that was presented to have either large disparities in socioeconomic resources between classes (high inequality condition) or low disparities (low inequality condition), while keeping the participants' objective socioeconomic standing constant across conditions. In Study 1 (pre-registered), participants (n = 167) completed the perceived societal inequality manipulation before a computerized food portion selection task to measure desired portion sizes for a variety of foods. Study 2 (n = 154) involved a similar design as Study 1, but with inclusion of a neutral control condition (no awareness of class disparities) followed by ad libitum consumption of potato chips.

RESULTS

While the high inequality condition successfully elicited perceptions of one's society as having greater socioeconomic inequalities between classes, it did not generate consistent feelings of personal socioeconomic disadvantage. Across both studies, we observed no differences between conditions in average selected portion sizes or actual energy intake.

CONCLUSIONS

Taken together with prior research on the effects of subjective socioeconomic disadvantage on increased energy intake, these findings suggest that perceptions of inequality in one's society may be insufficient to stimulate heightened energy intake in the absence of personal socioeconomic disadvantage or inadequacy.

Human nutritional intelligence underestimated? Exposing sensitivities to food composition in everyday dietary decisions

The social and cultural significance of food is woven into every aspect of our dietary behaviour, and it contributes to our complex interaction with food. To find order within this complexity scientists often look for dietary 'universals' - phenomena or basic principles that guide our food choice and meal size, irrespective of wider context. One such idea is that taste characteristics provide a signal for dietary composition (e.g., sweet taste signals carbohydrate). Others have suggested that behaviour is guided by learning and is based on associations that form between the flavour of a food and its post-ingestive effects. Despite a large body of research, evidence supporting both processes is equivocal, leading some to conclude that humans are largely indifferent to food composition. Here, we argue that human abilities to gauge the nutritional composition or value of food have been underestimated, and that they can be exposed by embracing alternative methods, including cross-cultural comparisons, large nutrition surveys, and the use of virtual portion-selection tools. Our group has focused on assessments of food choice and expected satiety, and how comparisons across everyday foods can reveal non-linear relationships with food energy density, and even the potential for sensitivity to micronutrient composition. We suggest that these abilities might reflect a complex form of social learning, in which flavour-nutrient associations are not only formed but communicated and amplified across individuals in the form of a cuisine. Thus, rather than disregarding sociocultural influences as extraneous, we might reimagine their role as central to a process that creates and imbues a 'collective dietary wisdom.' In turn, this raises questions about whether rapid dietary, technological, and cultural change disrupts a fundamental process, such that it no longer guarantees a 'nutritional intelligence' that confers benefits for health.

Imagine this: Visualising a recent meal as bigger reduces subsequent snack intake

Remembering a recent meal reduces subsequent intake of palatable snacks (i.e. the meal-recall effect), however, little is known about the factors which can potentiate this effect. The present experiment investigated whether a stronger meal-recall effect would be observed if recent consumption would be recalled in greater detail, than if it was recalled briefly. Moreover, it was investigated whether imagining a meal as bigger and more satiating than in reality could potentiate the meal-recall effect, and lead to lower intake. It was also explored whether mental visualisation tasks of a recent meal would affect the remembered portion size. Participants (N = 151) ate lunch at the laboratory, and then returned 3 h later to perform the imagination tasks and to participate in a bogus taste test (during which intake was covertly measured). Participants in the two main imagination task groups recalled the lunch meal and then either recalled the consumption episode in great detail or imagined the meal was larger and more filling than in reality. The results showed that imagining a recent meal as larger significantly reduced the quantity of biscuits eaten. However, contrary to the hypotheses, recalling a consumption episode in detail did not decrease snack intake. It was also shown that imagining a recent meal as larger than in reality did not lead participants to overestimate the true size of the meal. In fact, portion size estimations were significantly underestimated in that group. There were no significant estimation differences in any of the other groups. The results of this study suggest that the meal-recall effect can be an effective strategy to reduce food intake and may be amenable to strategic manipulation to enhance efficacy, but seems prone to disruption.

Implicit satiety goals and food-related expectations predict portion size in older adults: Findings from the BAMMBE cohort

Portion size selection is an indicator of appetite and within younger adults, is predicted by factors such as expected satiety, liking and motivations to achieve an ideal sensation of fullness (i.e., implicit satiety goals). Currently, there is limited research available on the determinants of portion size selection within older adults. Therefore, the current study aimed to examine the relationship between individual differences in implicit satiety goals, food-related expectations, and portion size selection in older adults. Free-living older adult Singaporeans (N = 115; Nmales = 62; age: M = 66.21 years, SD = 4.78, range = 60-83 years) participated as part of the Brain, Ageing, Microbiome, Muscle, Bone, and Exercise Study (BAMMBE). Participants completed questionnaires on their subjective requirements for experiencing different states of satiety and food-related expectations (i.e., liking, how filling) as well as a computerised portion size selection task. Using a multiple regression, we found that goals to feel comfortably full (B = 3.08, SE = 1.04, t = 2.96, p = .004) and to stop hunger (B = -2.25, SE = 0.82, t = -2.75, p = .007) significantly predicted larger portion size selection (R2 = 0.24, F(4,87) = 6.74, p < .001). Larger portion sizes (R2 = 0.53, F(5,90) = 20.58, p < .001) were also predicted by greater expected satiety (B = 0.47, SE = 0.09, t = 5.15, p < .001) and lower perceptions of how filling foods are (B = -2.92, SE = 0.77, t = -3.79, p < .001) but not liking (B = -0.09, SE = 0.91, t = -0.10, p = .925) or frequency (B = -18.42, SE = 16.91, t = -1.09, p = .279) of consumption of target foods. Comparing our findings to results of studies conducted with younger adults suggests the influence of factors such as satiety related goals on portion size selection may change with ageing while the influence of other factors (e.g., expected satiety/fullness delivered by foods) may remain consistent. These findings may inform future strategies to increase/decrease portion size accordingly to ensure older adults maintain an appropriate healthy weight.

Development and validation of a new methodological platform to measure behavioral, cognitive, and physiological responses to food interventions in real time

To fully understand the causes and mechanisms involved in overeating and obesity, measures of both cognitive and physiological determinants of eating behavior need to be integrated. Effectively synchronizing behavioral measures such as meal micro-structure (e.g., eating speed), cognitive processing of sensory stimuli, and metabolic parameters, can be complex. However, this step is central to understanding the impact of food interventions on body weight. In this paper, we provide an overview of the existing gaps in eating behavior research and describe the development and validation of a new methodological platform to address some of these issues. As part of a controlled trial, 76 men and women self-served and consumed food from a buffet, using a portion-control plate with visual stimuli for appropriate amounts of main food groups, or a conventional plate, on two different days, in a random order. In both sessions participants completed behavioral and cognitive tests using a novel methodological platform that measured gaze movement (as a proxy for visual attention), eating rate and bite size, memory for portion sizes, subjective appetite and portion-size perceptions. In a sub-sample of women, hormonal secretion in response to the meal was also measured. The novel platform showed a significant improvement in meal micro-structure measures from published data (13 vs. 33% failure rate) and high comparability between an automated gaze mapping protocol vs. manual coding for eye-tracking studies involving an eating test (ICC between methods 0.85; 90% CI 0.74, 0.92). This trial was registered at Clinical Trials.gov with Identifier NCT03610776.

Children's Portion Selection Is Predicted by Food Liking and Is Related to Intake in Response to Increased Portions

BACKGROUND

When children choose amounts of food to eat, it is unclear what influences the portions they select and whether their selections are related to the amounts they consume.

OBJECTIVES

Using a computer survey, we investigated the effect of food liking on portion selection in middle childhood and examined how children's selections were related to measured intake at meals in which portions of all foods were varied across 4 test days.

METHODS

Fifty-one children aged 7-10 y completed a computer survey of 20 common foods with a range of energy density. For each food, the survey presented sliding scales with 5 images varying in portion size and children indicated their liking and the amount they would eat at a specified meal or snack. On 4 test days in a randomized crossover design, children were served a meal of 6 foods from the survey with portions of 100%, 133%, 167%, or 200% of baseline amounts. Data were analyzed using random coefficients models.

RESULTS

Across the 20 foods used in the survey, portion selection ratings were predicted by food liking ratings (P < 0.0001). After accounting for liking, portion selection ratings did not vary by food energy density (P = 0.50). At the meals, intake of all 6 foods increased when larger portions were served (P = 0.002). Furthermore, the selected portion of a food on the survey was positively related both to intake of that food at the 100%-portion meal (P = 0.014) and to increased intake as larger portions were served (P < 0.0001).

CONCLUSIONS

Children aged 7-10 y were able to use a computer survey to choose food portions that predicted their measured intake in response to increased portions. The relation of liking to selection and intake indicates that to promote children's consumption of larger portions of low-energy-dense foods such as fruits and vegetables, these foods must be well liked by the children. This trial was registered at clinicaltrials.gov as NCT02759523.

Portions selected to stave off hunger are reduced when food is presented in an 'unusual' food-to-mealtime context: An implication for implicit satiety drivers

Research suggests that the role of expected satiety in influencing portion-size selection is reduced when food is presented in unusual food-to-mealtime contexts; however, the underlying mechanism has not been explored. Other research has revealed that different implicit satiety drivers (e.g., to stop momentary hunger or obtain complete fullness) are associated with different perceived levels of stomach fullness, portion-size selections and can change on instruction. The current study explored whether changes in expected satiety and ideal portions in congruous vs incongruous contexts can be explained by changes in implicit satiety drivers. Another aim was to investigate a previous exploratory finding suggesting that portions selected to stave off hunger are reduced when foods are presented in unusual food-to-mealtime contexts. At two trials (breakfast/lunch), participants (n = 40) selected a portion of typical lunch (pasta) and breakfast (porridge) foods via a psychophysical computer-based method 1) to stave off hunger for 5 h, and 2) as an ideal portion. Participants also indicated their perceived level of stomach fullness associated with 1) each portion, and 2) five implicit satiety drivers. Results revealed that a smaller average portion was selected to stave off hunger in incongruous (vs congruous) food-to-mealtime contexts (531 ± 229 vs 575 ± 236 kcal) (p = 0.008). This suggests that expected satiety is influenced by momentary context; foods are perceived to be more satiating when consumed in unusual (vs usual) contexts. Results also showed that implicit satiety drivers are malleable in regard to the portion size associated with a perceived level of stomach fullness and that this can vary contextually. These findings provide initial evidence to explain the psychological mechanism underlying the contextual differences observed in portion-size selections. Future work should explore longer-term impacts of consuming foods in unusual contexts.

Consumption of low-calorie sweetened drinks is associated with 'sweet satiation', but not with 'sweet-taste confusion': A virtual study

Originating from studies on rats, the 'taste confusion' hypothesis predicts that exposure to low-calorie sweeteners (LCS) will impair compensatory responses to sugar intake, resulting in increased overall calorie intake. We conducted a virtual study in which young adult human participants (n = 332), who differed in their history of exposure to sweet drinks (e.g., drank 'diet' (LCS) soft drinks or 'regular' (sugar-sweetened) soft drinks), imagined consuming a cheese sandwich and two-thirds of a 500 ml drink (still water, sparkling water, diet Coca Cola, regular Coca Cola, or semi-skimmed milk), or no drink, as a hypothetical lunch-time meal. They then used a screen-based tool to select the amount of a sweet snack (chocolate M&M's) or savoury snack (salted peanuts) that they would eat immediately with the remaining third of their drink (i.e., a total of 12 drink and snack combinations per participant). The results were inconsistent with the predictions of the taste confusion hypothesis; specifically, the extent to which consumption of sugar cola compared with water (still or sparkling) reduced snack intake did not differ between habitual diet (LCS) and habitual sugar soft-drink consumers. Other results showed a 'sweet satiation' effect (i.e., lower sweet versus savoury snack intake when the drink accompanying the meal was sweet compared with when it was water), and negligible compensation in snack food intake for the difference in the energy content of diet versus sugar cola.

The Effects of Acute Social Media Exposure on Body Dissatisfaction and Eating Behavior of Male and Female Students

Introduction: Experimental research has examined the effect of social media on body dissatisfaction, but little attention has been given to the impact on eating behavior. Across two studies, we tested the causal relationship between acute social media use, body dissatisfaction and eating behavior. Methods: In Study 1, 80 female participants (age: M = 20.75 years; BMI: M = 21.3) viewed their own Facebook account or a news website before completing a portion size selection task. In Study 2 (pre-registered), 148 participants (81 females; age: M = 20.92 years; BMI: M = 22.19), viewed their own or an experimenter-curated Instagram profile before consuming potato chips ad-libitum. Results: In Study 1, body dissatisfaction was significantly higher in participants who viewed Facebook (compared to a news website) and significantly mediated the effect of condition on portion size selection. In Study 2, regardless of condition females reported significantly smaller ideal body sizes and higher body dissatisfaction compared to males. When females reported a thinner body size as ideal, females in the personal Instagram consumed significantly less potato chips than those in the control Instagram condition. When males reported a smaller actual body size, males in the personal Instagram condition consumed significantly less potato chips than males in the control Instagram condition. Discussion: Findings suggest brief bouts of social media use may produce immediate disruptions to body image of both sexes, and restrained snack intake of females endorsing thin ideals.

Current appetite influences relative differences in the expected satiety of foods for momentary, but not hypothetical, expected satiety assessments

Research has shown that expected satiety is highly associated with portion-size selection and can vary (kcal-for-kcal) significantly between foods. However, research has not adequately investigated whether current appetite influences relative differences in the expected satiety of foods. This is important to explore to better understand how current motivational state influences food choice and portion selection. This study used 'hypothetical' and 'momentary' expected-satiety assessments to understand whether methods requiring a reflection on current motivational state [momentary] versus more hypothetical considerations when assessing expected satiety can influence the interpretation of results. It was hypothesised that current appetite would only influence relative differences in expected satiety between foods for momentary, but not hypothetical, expected satiety assessments. Participants (n = 54) were shown images of twelve foods, once when hungry and once when full. In each case, they selected a portion for each food to 1) match the expected satiety of a fixed-portion 'standard' food [hypothetical], and 2) stave off hunger until their next meal [momentary]. Results showed that the relative between-food comparison of expected satiety was stable for hypothetical (p=.73) but not momentary assessments (p<.001) suggesting that while current motivational state may influence food choice and portion selection in the moment, more generalised comparisons of the satiating abilities of foods (learned over a longer period) remain stable. This is important 1) for methods in future studies, as immediate dietary intake does not appear to influence hypothetical expected satiety, thus dietary control is not necessary before participants undertake these assessments, and 2) as it confirms that difficulties associated with dietary regulation may not be due to inaccurate hypothetical judgements about foods, but instead appear to be influenced by contextual nuances that occur in the moment.

Subjective socioeconomic disadvantage is indirectly associated with food portion selection through perceived disruption of personal resources during a nationwide COVID-19 stay-at-home order

In addition to its public health implications, the global COVID-19 pandemic has also produced significant disruptions to individuals' socioeconomic resources and opportunities. Prior research has suggested that low subjective socioeconomic status (SSES) may stimulate appetite and motivate increased energy intake. Here, we tested whether individuals experiencing lower levels of SSES (SSES disadvantage) during a nationwide stay-at-home order for COVID-19 exhibited preferences for larger food portion sizes through perceived disruptions to personal financial and material resources. Data was collected near the conclusion of a nationwide partial lockdown (Singapore's “Circuit-Breaker” from April to June 2020). Participants (N = 295) completed an online survey involving a measure of SSES, the Coronavirus Impacts Questionnaire, and a food portion selection task where participants estimated the portion size they prefer to consume for a range of common foods. SSES disadvantage was associated with selection of smaller average portion sizes. Yet, a significant indirect effect of coronavirus impact was observed in this relationship, such that participants experiencing greater SSES disadvantage selected larger portion sizes through the effect of greater perceived impacts of COVID-19 to one's financial/material resources (controlling for one's actual level of income). These findings further support the idea that perceived deprivation and insecurity of important resources (financial, social, material) may influence intentions to consume greater amounts of energy. Consequently, systematic societal disruptions to such resources may reinforce and perpetuate potentially obesogenic eating behaviors of populations that are especially vulnerable to such shocks (i.e., people experiencing SSES disadvantage).

The effects of nutrition and health claims on the nutrient composition of single and subsequent meal servings

Nutrition and health claims (NHCs) can help individuals make better food choices. While NHCs have been found to influence consumer perceptions and consumption, there has been less focus on how claims influence the nutritional composition of servings. There has also been little attention paid to longer term or compensatory effects of claims on subsequent food selection. This manuscript details two studies considering these matters. Study 1 (n = 60) was a within-subjects experiment to measure the impact of NHCs on food selection and nutritional composition at single meal servings. Participants served from three fake food buffet meal stations (breakfast, hot meal, snacks) with NHCs present or absent. Study 2 (n = 55) was a within-subjects experiment to examine the impact of NHCs on food selection and nutritional composition at a subsequent meal. Participants served from a fake food buffet breakfast with or without NHCs followed by a lunch without NHCs. In study 1, while results varied for different meals, the presence of claims was found to significantly reduce the amount of energy, fat, saturated fat, sugar, carbohydrates, and sodium, and increase the amount of protein in meals that were served. Results for fibre were mixed. In addition, NHCs increased the quantity of food served in the snacks condition. There was no evidence of claims at breakfast impacting the nutritional composition of subsequent lunch servings in study 2. Despite claims potentially increasing serving quantities, the nutritional composition of chosen servings was more encouraging and claims may help individuals to meet recommended nutritional daily guidelines. These findings have wider implications in terms of government policy, food reformulation, and the continuing debate around the use of nutrient profiling regulations for products carrying claims.

Gender, Age, Hunger, and Body Mass Index as Factors Influencing Portion Size Estimation and Ideal Portion Sizes

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.

Influence of social-normative information on the modeling of food-related decisions

Social modeling is a powerful influence on people's food intake: When there is a clear and consistent norm, people eat more when eating with someone who eats a lot and eat less when eating with someone who eats only a little. In three studies, the present research examined how clear versus ambiguous social-normative information influences the modeling of food-related decisions. Using a novel online decision-making paradigm, female participants (total N = 1042) were provided with information about how many cookies previous participants had supposedly selected (no information was provided in the control condition), and then decided how many cookies they would choose for a snack. When there was a clear and consistent norm, the typical social modeling effect was observed. When there was a small number of "dissenters" whose responses conflicted with the norm set by the majority, participants' cookie selection still conformed to the behaviour of the majority (Studies 1 and 2). It was only when the behaviour of the previous participants was highly ambiguous that participants behaved as if they had been given no normative information (Study 3). By demonstrating that, except in extreme cases, people use the available information to discern a social norm that influences their behaviour, these findings highlight the power of social norms related to food-related decisions.

Micronutrients and food choice: A case of 'nutritional wisdom' in humans?

Many reports show that non-human animals have the ability to select foods based on their micronutrient composition. However, it is unclear whether humans also have this ability, and we have lacked appropriate methods to investigate this question. In response to this challenge, we developed an approach that derives evidence from patterns of choices across a range of food images. In two studies (Study 1, N = 45; Study 2, N = 83) adults selected one of two pairs of fruits and vegetables in a series of trials (N = 210). Consistent with variety seeking, they preferred 'varied' over 'monotonous' pairs (same-food pairs were less attractive). However, and even after controlling for explicit nutritional knowledge (Study 2) and food energy density (Study 1 and 2), we observed a significant tendency to select pairings that offered: i) greater total micronutrient intake and ii) greater 'micronutrient complementarity' (MC), i.e., a broader range of micronutrients. In a separate analysis, a similar pattern was observed in two-component meals (e.g., steak and fries) drawn from a large national nutrition survey in the UK (1086 records). Specifically, the MC of these meals was greater than would be predicted by chance (p < .0001) and when a meal provided an excess of micronutrients (>100% daily recommended amount) then this occurred less often than by chance (p < .0001), i.e., 'micronutrient redundancy' was avoided. Together, this work provides new evidence that micronutrient composition influences food choice (a form of 'nutritional wisdom') and it raises questions about whether nutritional requirements are otherwise met through dietary 'variety seeking'. In turn, it also exposes the potential for a complexity in human dietary decision making that has not been recognised previously.

The Universal Eating Monitor (UEM): objective assessment of food intake behavior in the laboratory setting

The Universal Eating Monitor was a term used to describe a device used in a laboratory setting that enabled investigators to measure, with the same instrument, the rate of eating either solids or liquids, hence the term “universal”. It consisted of an electronic balance placed in a false panel under a table cloth on which could be placed a food reservoir that contained either solid or liquefied food. The device was created in order to determine whether rates of eating differed in pattern between solid and liquid foods. An acceptable mixture of foods of identical composition that could be served as either solid or blended as a liquid was used to test the hypothesis that eating rate and intake were affected by physical composition. A best-fitting mathematical function (intake was quadratic function of time, with coefficients varying among foods used and experimental conditions), quantified intake rates. The device was used to test a variety of mechanisms underlying food intake control. Eating rates were linear when solid foods were used, but negatively accelerated with liquids. Overall, intake did not differ between solid and liquefied food of identical composition. Satiation on a calorie for calorie basis was different among foods, but physical composition interacted with energy density. Hormones and gastric distension were strong influences on food intake and rate of eating. Individuals with bulimia nervosa and binge eating disorder ate more than individuals without these disturbances. Intake in social and individual contexts was identical, but the rate of eating was slower when two individuals dined together. The eating monitor has been a useful instrument for elucidating controls of food intake and describing eating pathology.

Does labelling a food as 'light' vs. 'filling' influence intake and sensory-specific satiation?

Although several studies have investigated the influence of nutrition labelling on food intake, the effect of labels indicating a food's satiating power on food intake and sensory-specific satiation (SSS) is poorly understood. We investigated whether providing information about the satiating power of a meal affects intake and SSS. Participants (19 men and 18 women) consumed the same test meal of pasta salad ad libitum on two occasions, once described as 'light' and once as 'filling'. SSS was determined as the change in liking of the flavor and desire to eat the test meal before and after consumption, compared to seven uneaten foods. As hypothesized, intake increased by a mean (±SD) of 31 ± 59 g and 42 ± 81 kcal when the meal was labelled 'light' as opposed to 'filling' (p < 0.01). After eating, ratings for both liking and desire to eat decreased significantly more for the test meal than for the uneaten control foods (p < 0.001), demonstrating SSS. These relative changes in liking and desire to eat did not differ between the label conditions, despite differences in intake. Furthermore, accounting for amount consumed, the magnitude of SSS did not differ between the label conditions, which suggests that it did not explain the effect of the labels on intake. This study shows that labels indicating the satiating power of a meal can affect intake, warranting caution in the use of such labels on products intended to reduce intake.

Multi-component food-items and eating behaviour: What do we know and what do we need to know?

Multi-component food-items are single food products that comprise more than one food class, brought together usually via some form of processing. Importantly, individual components of the food-item remain discernible and sensorially distinguishable from each other (e.g., chocolate chip cookies or 'choc ice'). Despite a sizable research literature on the formulation of such products, there lacks a concomitant research literature on the effect(s) of multi-component food-items (compared to single component food-items) on eating behaviour. Considerable previous research has investigated the effect of multiple separate food items on food intake, portion size selection and palatability. However, studies rarely use test foods that capture the physical or chemical interactions between components that are characteristic of multi-component foods. Nevertheless, previous research and relevant theory allow us to generate hypotheses about how multi-component foods may affect eating behaviour; consideration of food variety and perceived sensory complexity suggest that consumption of multi-component foods are likely to increase perceived palatability of such foods, self-selected portion size and food intake. Moreover, many (but not all) multi-component foods would be considered ultra-processed, which is a driver of food intake in and of itself. One possibility is that food components brought together as part of a multi-component food-item interact to strongly drive eating behaviour. To explore this idea, researchers will need to work across disciplines to address various practical and methodological barriers including the technical preparation of test foods.

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.

Socioeconomic position, energy labelling and portion size selection: An online study comparing calorie and physical activity calorie equivalent (PACE) labelling in UK adults

Limited research has examined the impact of energy labelling on portion size selection. It is also unclear whether physical activity calorie equivalent (PACE) is more effective than standard kilocalorie (kcal) energy labelling in promoting healthier dietary behaviour and whether effectiveness varies based on socioeconomic position (SEP). In the present online study, 1667 UK adults of lower and higher SEP made virtual portion size selections for 18 common main meal foods under one of four conditions: kcal labelling only, PACE labelling only, kcal and PACE labelling, no labelling. Contrary to predictions, participants in the kcal labelling condition (+55 kcal, p < 0.001) chose larger portion sizes compared to the no labelling condition, whereas the PACE labelling (−17 kcal, p = 0.065) and no labelling condition did not significantly differ. The presence of PACE information on labels was associated with selection of significantly smaller portions when compared to labels that only included kcal information. Effects of labels on portion size selection were not moderated by participant SEP in primary analyses. The present study of virtual portion size selections suggests that kcal labelling resulted in larger portion size selections than no labelling, but this counter-intuitive effect was attenuated when kcal and PACE labelling were combined. Further research examining the impact of PACE labelling on real-world food selection in participants of lower and higher SEP is now warranted.

Recalled and momentary virtual portions created of snacks predict actual intake under laboratory stress condition

Virtual portion tasks have been used to predict food intake in healthy individuals, severity of illness in individuals with anorexia nervosa, and weight loss in bariatric surgery patients. Whether portion creation in response to a recalled interpersonal stress ("recalled stress portions") could be used as a proxy for ad lib intake, after a stressor, remains untested, and the mechanism supporting this relationship is unclear. The present study's goals were: 1) to validate virtual portion tasks as proxies for actual food intake in a stressful context and 2) to test a causal pathway in which these virtual stress portions predict ad lib intake after stress. We proposed that this relationship is mediated by virtual portions created the moment after laboratory stress or rest manipulation (momentary portions), and before the participant actually ate food. At screening, 29 healthy undergraduate white women created virtual portions of eight snacks (apples, olives, potato chips, pretzels, caramel popcorn, milk chocolate) that they typically eat and also portions they recall eating in response to a stressful interpersonal situation. In addition, after a Trier Social Stress Test, or a rest period, on separate days in counterbalanced order, participants created 'momentary' virtual portions of the same snacks presented during screening, and then were given potato chips, mini golden Oreos, and M&Ms to eat. Recalled stress (b = 0.07 ± 0.02, p = 0.003), and momentary stress (b = 0.12 ± 0.02, p = 0.00001), portions of milk chocolate accounted for 29% and 51%, respectively, of the variance in ad lib stress intake of M&Ms. Typical (b = 0.15 ± 0.07, p = 0.03), and momentary rest (b = 0.21 ± 0.06, p = 0.002), portions of chips accounted for 16% and 31%, respectively, of the variance in ad lib rest intake of chips. The causal pathway from recalled stress portion to ad lib stress snack intake was completely mediated by momentary stress portion for milk chocolate and M&Ms (β = 0.04 ± 0.02, z = 2.4, p = 0.0154). These findings illustrate the planning and recall components of eating in response to stress, but not necessarily under rest conditions. This recalled stress virtual portion paradigm has clinical and research value in that it can detect those who overconsume in response to stress.

Development of a Simplified Portion Size Selection Task

Portion size is an important determinant of energy intake and the development of easy to use and valid tools for measuring portion size are required. Standard measures, such as ad libitum designs and currently available computerized portion selection tasks (PSTs), have several limitations including only being able to capture responses to a limited number of foods, requiring participants’ physical presence and logistical/technical demands. The objective of the current study was to develop and test robust and valid measures of portion size that can be readily prepared by researchers and be reliably utilized for remote online data collection. We developed and tested two simplified PSTs that could be utilized online: (1) portion size images presented simultaneously along a horizontal continuum slider and (2) multiple-choice images presented vertically. One hundred and fifty participants (M = 21.35 years old) completed both simplified PSTs, a standard computerized PST and a series of questionnaires of variables associated with portion size (e.g., hunger, food item characteristics, Three Factor Eating Questionnaire). We found average liking of foods was a significant predictor of all three tasks and cognitive restraint also predicted the two simplified PSTs. We also found significant agreement between the standard PST and estimated portion sizes derived from the simplified PSTs when accounting for average liking. Overall, we show that simplified versions of the standard PST can be used online as an analogue of estimating ideal portion size.

When do children learn how to select a portion size?

The reduction of portion sizes supports weight-loss. This study looks at whether children have a conceptual understanding of portion size, by studying their ability to manually serve a portion size that corresponds to what they eat. In a clinical setting, discussion around portion size is subjective thus a computerised portion size tool is also trialled, with the portion sizes chosen on the screen being compared to amounts served manually. Children (n = 76) age 5-6, 7-8 and 10-11 were asked to rate their hunger (VAS scale), liking (VAS scale) and 'ideal portion size for lunch' of eight interactive meal images using a computerised portion size tool. Children then manually self-served and consumed a portion of pasta. Plates were weighed to allow for the calculation of calories served and eaten. A positive correlation was found between manually served food portions and the amount eaten (r = 0.53, 95%CI [0.34, 0.82, P < .001), indicating that many children were able to anticipate their likely food intake prior to meal onset. A regression model demonstrates that age contributes to 9.4% of the variance in portion size accuracy (t(68) = -2.3, p = .02). There was no relationship between portion size and either hunger or liking. The portion sizes chosen on the computer at lunchtime correlated to the amount manually served overall (r = .34, 95%CI [0.07, 0.55], p < .01), but not in 5-6-year-old children. Manual portion-size selection can be observed in five-year olds and from age seven, children's 'virtual' responses correlate with their manual portion selections. The application of the computerised portion-size tool requires further development but offers considerable potential.

The serving temperature effect: Food temperature, expected satiety, and complementary food purchases

We show that the temperature at which foods and beverages are served impacts consumers' complementary purchases, defined as additional foods and beverages purchased for a consumption episode. Across a series of studies, including field studies and controlled laboratory experiments, we show that consumers choose more complementary food items when they consume or intend to consume a food or beverage served cold rather than hot. This occurs because cold consumables are expected to be less satiating compared to hot consumables. Serving temperatures that increase complementary purchasing may enhance the firm's bottom line, but could add unnecessary calories to the meal, and thus is of interest to both consumers and managers.

Development of MacroPics: A novel food picture set to dissociate the effects of carbohydrate and fat on eating behaviors

Emerging evidence suggests that fat and carbohydrate interact to potentiate the reward value of food (DiFeliceantonio et al., 2018). The primary goal of the current study was to develop a novel picture set to facilitate research into the effects of macronutrient composition on food choice and eating behavior. Toward this aim, we developed "MacroPics." In Experiment 1, we photographed 120-kcal portions of 60 snack foods falling into one of the three macronutrient categories: (1) mostly carbohydrate, (2) mostly fat, or (3) a combination of fat and carbohydrate. Sixty-one participants rated the images for liking, familiarity, frequency of consumption, healthiness, estimated energy content (in kcal), and expected satiation. A subset of these images consisting of 36 items was then selected in an iterative process to minimize differences in ratings between the macronutrient categories while simultaneously ensuring similar within-category variability on a number of food characteristics (e.g., energy density, portion size, retail price) and visual properties (e.g., color, complexity, visual area). In Experiment 2, an independent sample of 67 participants rated the pictures of the final 36-item MacroPics. Both experiments reveal similar participant ratings across categories for item liking, familiarity, frequency, healthiness, and estimated energy content. Protein content was higher in the fat compared to the carbohydrate and combination categories, leading to higher ratings of estimated satiety and energy density for fatty foods. Item and macronutrient category characteristics of the final MacroPics set are reported.

Reliability and responsiveness of virtual portion size creation tasks: Influences of context, foods, and a bariatric surgical procedure

Food portion size influences energy intake and sustained high-energy intake often leads to obesity. Virtual portion creation tasks (VPCTs), in which a participant creates portions of food on a computer screen, predict intake in healthy individuals. The objective of this study was to determine whether portions created in VPCTs are stable over time (test-retest reliability) and responsive to factors known to influence food intake, such as eating contexts and food types, and to determine if virtual portions can predict weight loss. Patients with obesity scheduled for bariatric surgery (n = 29), and individuals with a normal BMI (18.5-24.9 kg/m2, controls, n = 29), were instructed to create virtual portions of eight snack foods, which varied in energy density (low and high) and taste (sweet and salty). Portions were created in response to the following eating situations, or "contexts": What they would a) eat to stay healthy (healthy), b) typically eat (typical), c) eat to feel comfortably satisfied (satisfied), d) consider the most that they could tolerate eating (maximum), and e) eat if nothing was limiting them (desired). Tasks were completed before, and 3 months after, surgery in patients, and at two visits, 3 months apart, in controls. Body weight (kg) was recorded at both visits. Virtual portions differed significantly across groups, visits, eating contexts, energy densities (low vs. high), and tastes (sweet vs. salty). Portions created by controls did not change over time, while portions created by patients decreased significantly after surgery, for all contexts except healthy. For patients, desired and healthy portions predicted 3-month weight loss. VPCTs are replicable, responsive to foods and eating contexts, and predict surgical weight loss. These tasks could be useful for individual assessment of expectations of amounts that are eaten in health and disease and for prediction of weight loss.

Snack Portion Sizes for Preschool Children Are Predicted by Caregiver Portion Size, Caregiver Feeding Practices and Children's Eating Traits

Caregivers are mostly responsible for the foods young children consume; however, it is unknown how caregivers determine what portion sizes to serve. This study examined factors which predict smaller or larger than recommended snack portion sizes in an online survey. Caregivers of children aged 2 to 4 years were presented with 10 snack images, each photographed in six portion sizes. Caregivers (n = 659) selected the portion they would usually serve themselves and their child for an afternoon snack. Information on child eating traits, parental feeding practices and demographics were provided by caregivers. Most caregivers selected portions in line with recommended amounts for preschool children, demonstrating their ability to match portion sizes to their child's energy requirements. However, 16% of caregivers selected smaller than recommended low energy-dense (LED, e.g., fruits and vegetables) snacks for their child which was associated with smaller caregiver's own portion size, reduced child food liking and increased satiety responsiveness. In contrast, 28% of caregivers selected larger than recommended amounts of high energy-dense (HED, e.g., cookies, crisps) snacks for their child which were associated with larger caregiver's own portion size, greater frequency of consumption, higher child body mass index (BMI), greater pressure to eat and lower child food liking. These findings suggest that most caregivers in this study select portions adjusted to suit their child's age and stage of development. Future interventions could provide support to caregivers regarding the energy and nutrient density of foods given the relatively small portion sizes of LED and large portions of HED snacks offered to some children.

Served Portion Sizes Affect Later Food Intake Through Social Consumption Norms

Portion sizes of commercially available foods have increased, and there is evidence that exposure to portion sizes recalibrates what is perceived as 'normal' and subsequently, how much food is selected and consumed. The present study aims to explore the role of social (descriptive and injunctive) and personal portion size norms in this effect. Across two experiments, participants were either visually exposed to (Study 1, N = 329) or actually served (Study 2, N = 132) a smaller or larger than normal food portion. After 24 h, participants reported their intended consumption (Study 1) or served themselves and consumed (Study 2) a portion of that food and reported perceived portion size norms. In Study 1, visual exposure to portion size did not significantly affect intended consumption and perceived portion size norms. In Study 2, participants consumed a smaller portion of food when they were served a smaller rather than a larger portion the previous day, which was mediated by perceived descriptive and injunctive social (but not personal) portion size norms. Results suggest that being served (but not mere visual exposure to) smaller (relative to larger) portions changes perceived social norms about portion size and this may reduce future consumption of that food.

Health, pleasure, and fullness: changing mindset affects brain responses and portion size selection in adults with overweight and obesity

BACKGROUND

Increased portion size is an essential contributor to the current obesity epidemic. The decision of how much to eat before a meal begins (i.e. pre-meal planning), and the attention assigned to this task, plays a vital role in our portion control.

OBJECTIVE

We investigated whether pre-meal planning can be influenced by a shift in mindset in individuals with overweight and obesity in order to influence portion size selection and brain activity.

DESIGN

We investigated the neural underpinnings of pre-meal planning in 36 adults of different weight groups (BMI < 25 kg/m² and BMI ≥ 25 kg/m²) by means of functional magnetic resonance imaging. To examine the important role of attentional focus, participants were instructed to focus their mindset on the health effects of food, expected pleasure, or their intention to stay full until dinnertime, while choosing their portion size for lunch.

RESULTS

We observed that participants of all weight groups reduced their portion size when adopting a health mindset, which was accompanied by enhanced activation of the self-control network (i.e. left prefrontal cortex). Fullness and pleasure mindsets resulted in contrasting reward responses in individuals with overweight and obesity compared to normal-weight individuals. Under the pleasure mindset, persons with overweight and obesity showed heightened activity in parts of the taste cortex (i.e. right frontal operculum), while the fullness mindset caused reduced activation in the ventral striatum, an important component of the reward system. Moreover, participants with overweight and obesity did not modify their behaviour under the pleasure mindset and selected larger portions than the normal-weight group.

CONCLUSIONS

We were able to identify specific brain response patterns as participants made a final choice of a portion size. The results demonstrate that different brain responses and behaviours during pre-meal planning can inform the development of effective strategies for healthy weight management.

Lower socioeconomic status is associated with higher intended consumption from oversized portions of unhealthy food

Socioeconomic status is one of the strongest predictors of obesity, and of living in deprived neighbourhoods with unhealthy food environments. Little is known, however, about the psychological processes that translate features of such environments into socioeconomic differences in eating behaviour. One important feature of unhealthy food environments is the prevalence of oversized portions of unhealthy food. The present study tested whether individuals with lower socioeconomic status intend to consume more from large portions than those with higher socioeconomic status, and examined the psychological processes underlying this effect. A large-scale online experiment was conducted in which participants (N = 511) indicated how much they would eat from small and large portions of healthy and unhealthy snacks. The mediating effects of trait impulsivity and perceptions of how much was considered appropriate to eat were also assessed. Participants with lower socioeconomic status intended to eat more from the large portions than from the small portions of the unhealthy snacks, which would equate to a potential 15-22% increase in energy intake. These effects were partially mediated by trait impulsivity and perceptions of how much is appropriate to eat. These findings point to a significant health burden of low socioeconomic status: when exposed to unhealthy food environments, specific psychological processes might increase the amount of unhealthy food those with lower socioeconomic intend to consume. This study critically informs the emerging understanding of the psychology of socioeconomic status and eating behaviour.

Preschoolers exhibit conformity to computer-simulated food portion selection behaviors of remote peers

Children have been found to rely on others for food choice and food intake cues, but it is unclear whether a similar type of social modeling occurs for food portion selection, especially among young children. Given that portion size predicts energy intake, it is important to understand the role of social influence on portion selection behavior early in life. The present study aimed to determine preschoolers' conformity to food portion selection patterns of remote peers using a computerized Portion Selection Task and examined the role of parents' feeding styles in children's susceptibility to others' food portion choices. Seventy-five 3-6 year old Singaporean children (M = 62 ± 0.72 months) were asked to make food portion selections of high-energy-density (ED) foods and low-ED foods both independently and after having viewed remote peers' portion selections of the same foods. In the unhealthy peers condition, children saw peers choose large portions of high-ED foods and small portions of low-ED foods, while in the healthy peers condition, children saw peers select large portions of low-ED foods and small portions of high-ED foods. Parents were surveyed about their child feeding practices. Results revealed that participants exhibited conformity to the portion sizes of remote peers for both high-ED and low-ED foods under the healthy peers condition, but only marginally for high-ED foods under the unhealthy peers condition. Parents' higher restriction of foods for child's health was marginally associated with lower conformity to peers' portion selections of unhealthy foods and higher conformity to peers' portion selections of healthy foods. This study provides support for social modeling of food portion selection among young children, but the extent of social modeling may be contingent on characteristics of the food.

Food portion size influences accompanying beverage selection in adults

When trying to reduce food portion size, it is important that meal satisfaction is, as far as possible, preserved. Otherwise, individuals may select accompaniments to the meal (e.g., snacks, beverages) to achieve satisfaction and, in doing so, negate any benefit of the original portion size reduction. This study investigated whether varying portion sizes of food would influence choice of accompanying beverages. That is, when presented with a food portion size that is smaller or larger than their ideal, an individual may compensate by choosing a beverage based on its satiating and/or orosensory properties to balance the expected satiation and satisfaction of a meal. Data from an online interactive study (n = 93) was analysed using multilevel ordinal logistic regression models. Food portion size (100, 300, 500, 700, or 900 kcal) predicted beverage choice (water, low-energy sweetened beverage, high-energy sweetened beverage). For example, the sweetened beverages were more likely to be selected with small food portion sizes (p < .001). Participant ideal food portion size did not interact with this relationship. Participants appear to have recognised that sweetened beverages provide flavour and/or energy, and used them to compensate for a smaller meal. While switching to a low-energy beverage with an increased food portion size is advantageous for energy balance, choosing a high-energy beverage with a decreased food portion size is likely to be detrimental for those attempting to reduce energy intake and body weight.

The Cognitive Control of Eating and Body Weight: It's More Than What You "Think"

Over the past decade, a great deal of research has established the importance of cognitive processes in the control of energy intake and body weight. The present paper begins by identifying several of these cognitive processes. We then summarize evidence from human and nonhuman animal models, which shows how excess intake of obesity-promoting Western diet (WD) may have deleterious effects on these cognitive control processes. Findings that these effects may be manifested as early-life deficits in cognitive functioning and may also be associated with the emergence of serious late-life cognitive impairment are described. Consistent with these possibilities, we review evidence, obtained primarily from rodent models, that consuming a WD is associated with the emergence of pathophysiologies in the hippocampus, an important brain substrate for learning, memory, and cognition. The implications of this research for mechanism are discussed within the context of a “vicious-cycle model,” which describes how eating a WD could impair hippocampal function, producing cognitive deficits that promote increased WD intake and body weight gain, which could contribute to further hippocampal dysfunction, cognitive decline, and excess eating and weight gain.