Modeling of food intake: a meta-analytic review

Evidence of a self-serving bias in people's attributions for their food intake

People often fail to acknowledge external influences on their food intake, but there might be some circumstances in which people are willing to report that those external factors influenced their behavior. This study examined whether participants who believed that they had overeaten would indicate that the portion size they were served influenced their food intake. Participants (119 women) ate a pasta lunch at two separate sessions, one week apart. At the second session, participants were randomly assigned to receive either a regular portion of pasta (the same portion as the first session) or a large portion of pasta (a portion that was twice the size), and to receive false feedback about their food intake indicating that they had either eaten about the same as or substantially more than they had at the previous session. Participants were then asked to indicate the extent to which the amount of food served influenced how much they ate at that second session. Compared to participants who were informed that they had eaten the same amount across the two sessions, those who were informed that they ate more at the second session reported a stronger influence of the amount of food served if they also received a large portion of pasta, but not if they received a regular portion of pasta. These findings suggest that the willingness to implicate external influences (e.g., portion size) on one's food intake may be driven by a self-serving bias, providing an "excuse" for overeating. However, the external cue must be salient enough to be a plausible explanation for one's behavior.

Social norms and young adults' self-reported meat and plant-based meal intake: Findings from two online cross-sectional studies

Plant-based eating is beneficial for human and planetary health. It is important to identify factors which may encourage people to reduce meat, and increase plant-based meal intake. Perceived social norms are associated with meat and plant-based meal intake in adults, however, less is known about the relationship between perceived social norms and young adults' own self-reported meat and plant-based eating in general, and in different social contexts. Across two online studies we examined this. In Study 1 (n = 217 young adults, aged 18-25 years, mean age = 19.50 years, SD = 1.37 years, mean BMI = 24.21, SD = 5.45, 91% cisfemale, 92.0% omnivores), perceived descriptive (the perceived behaviour of others) and injunctive (the perceived approval of others) norms were measured in general. In study 2 (n = 151 young adults aged 18-25 years, mean age = 19.62 years, SD = 1.50 years, mean BMI = 24.32, SD = 4.99, 88.8% cisfemale, 71.1% omnivore), perceived descriptive and injunctive norms were examined in a variety of social contexts. In Study 1, perceived descriptive norms about friends were associated with self-reported meat, and descriptive norms about peers and friends, and injunctive norms about friends were positively associated with self-reported plant-based meal intake. In Study 2, descriptive norms about friends were associated with self-reported meat intake in fast-food restaurants and at friends' houses, and injunctive norms about friends were associated with meat intake in restaurants. There were no other significant associations between either type of social norm and meat or plant-based meal intake. We provide the first evidence that peers and friends may be relevant for plant-based meal intake, and only friends may be relevant for meat intake. Further research is needed to examine people's actual food intake, and in longitudinal studies to rule out reverse causality.

I'll have what She's having (but not what They're having): The moderating role of group membership in the effect of social norms on food choice in an online environment

The modern food-rich environment has contributed to the rise of unhealthy diets linked to noncommunicable diseases. Previous in-person research has found that the effect of social norms on food intake is greater when set by a perceived in-group member relative to an out-group member. Given recent increased social media use, we investigated whether this effect of group membership extends to food choices and to normative information presented remotely online. Participants (N = 179 female university students, 18-32 years) viewed a Facebook page pertaining to either their university (in-group) or a rival university (out-group). They were presented with either a healthy or an unhealthy norm via a post in which a student discussed their order at a café on the relevant campus. Food choice was assessed through an online menu where participants were asked to order one main, side, and dessert dish. As predicted, participants who viewed the healthy norm ordered a higher percentage of healthy items (especially in the desserts category) relative to those who viewed the unhealthy norm. However, this effect was significant only for those in the in-group condition; there was no such pattern for participants in the out-group condition. These findings provide insight into the role of group membership in the effect of social norms, and have practical implications regarding the design of identity-based social media health campaigns to promote healthier eating behaviours.

The food and beverage cues in digital marketing model: special considerations of social media, gaming, and livestreaming environments for food marketing and eating behavior research

Digital marketing to children, teens, and adults contributes to substantial exposure to cues and persuasive messages that drive the overconsumption of energy dense foods and sugary beverages. Previous food marketing research has focused on traditional media, but less is known about how marketing techniques translate within digital platforms, such as social media, livestreaming, and gaming. Building upon previous theories and models, we propose a new model entitled food and beverage cues in digital marketing (FBCDM). The FBCDM model specifies key marking elements and marketing integration strategies that are common on digital platforms and are hypothesized to enhance the effects of advertising and incentive sensitization process. FBCDM also categorizes measurable outcomes into three domains that include brand, food, and social outcomes. Additionally, repeated marketing exposure and the resulting outcomes are hypothesized to have long term consequences related to consumer markets, consumption behavior, culture, and health. We include a discussion of what is currently known about digital marketing exposure within the outcome domains, and we highlight gaps in research including the long-term consequences of digital marketing exposure. The FBCDM model provides a conceptual framework to guide future research to examine the digital marketing of food and beverages to children and adolescents in order to inform government and industry policies that restrict the aggressive marketing of products associated with obesity and adverse diet related outcomes.

Exposure to models' negative facial expressions whilst eating a vegetable decreases women's liking of the modelled vegetable, but not their desire to eat

Introduction

Food enjoyment can be conveyed through facial expressions. Observing others' enjoyment of food has been found to influence adults' desirability of liked and disliked food. Exposing adults to other eaters enjoying nutritious foods that are typically disliked (e.g., vegetables) could enhance the consumption of vegetables by young adults. However, this remains to be examined in young adult populations. This study examined the effect of models' facial expressions towards raw broccoli on young adult women's change in liking and change in desire to eat a modelled vegetable (raw broccoli) and a non-modelled vegetable (cucumber).

Methods

Young adult women (N = 205) were randomised to watch a video of unfamiliar adult models eating raw broccoli with a positive, negative, or neutral facial expression. Participants' change in liking and change in desire to eat the modelled and non-modelled vegetable was examined.

Results

Observing models conveying negative facial expressions whilst eating raw broccoli resulted in a statistically significant reduction in liking ratings of broccoli, but not cucumber. There was no effect of models' facial expressions on the change in desire to eat foods.

Discussion

These findings suggest that watching others express a negative facial expression whilst eating a raw vegetable reduces women's liking of the modelled vegetable, in the absence of a significant change to their desire to consume these foods. This highlights the power of others' negative facial expressions on food liking. Further work is needed to establish the effect of others' facial expressions on vegetable intake.

Using Non-Violent Discipline Tools: Evidence Suggesting the Importance of Attunement

Training in non-violent discipline is important to prevent violence against children and ensure that their caregivers remain a safe base for them. This paper aims to deepen understanding of non-violent discipline by exploring attunement as a mechanism in the effectiveness of non-violent discipline tools. Attunement describes the sensitive responsiveness of caregivers towards their children and has been found to be central to the formation of secure attachment bonds and development of self-regulation. It includes understanding or being "in tune with" the child's needs and signals, matching these with appropriate responses. The objective of this paper is to explore attunement in relation to non-violent discipline. Peer-reviewed systematic reviews previously included in a systematic overview of evidence on non-violent discipline options were screened for information relevant to attunement. All reviews were published in English between 1999 and 2018 and offered evidence on at least one non-violent discipline tool. Although no reviews explicitly addressed attunement, evidence was found suggesting its importance in the use and effectiveness of discipline methods. Research directly investigating attunement in discipline is needed.

A social norm intervention increases liking and intake of whole crickets, and what this tells us about food disgust

Edible insects are healthy and sustainable but are rejected as food in Western populations due to disgust. We tested the effectiveness of written interventions to reduce disgust and increase intake of whole crickets. Cricket acceptance after reading a descriptive social norm or food preparation intervention passage was compared with a control passage, and an unfamiliar but non-disgusting food (leblebi, roasted chickpeas). Participants (N = 120) were randomised to one of four conditions (control + crickets, food preparation + crickets, social norm + crickets and control + leblebi). Outcome measures included taste pleasantness, desire to eat, food intake and, to measure disgust, self-report disgust, tactile sensitivity and latency to eat. In the control condition, crickets were rejected due to disgust and low desire to eat. In comparison, in the social norm condition, crickets were rated as tasting more pleasant, more desirable, and less disgusting, and intake was greater. The food preparation passage had a small but positive effect on cricket intake. For the first time, this study shows that a descriptive social norm can affect eating behaviour even when a food is disgusting; however, a food preparation intervention cannot overcome high disgust. The pattern of results suggested that expected and perceived taste pleasantness affects disgust. Therefore, taste quality and normalising consumption are targets for promoting acceptance of insects, and probably other novel, sustainable foods.

Changes in food cue reactivity through affective and nonaffective touch: An event-related potential study

Affective touch (gentle/slow brushing of the skin) can facilitate the allocation of processing resources to simultaneously present stimuli from different modalities. The present event-related potential (ERP) study investigated whether affective touch can enhance attention to visual cues of healthy food. Female participants (n = 117) were randomly assigned to three different groups that either received affective touch, nonaffective touch (fast brushing of the skin), or no touch during the presentation of pictures of healthy food (fruits and vegetables) and non-food. Electrocortical markers of motivated attention (frontal/parietal P300, late positive potential: LPP) and reported appetite for the depicted food items were compared between the three groups. Nonaffective touch was associated with reduced amplitudes of the frontal P300/LPP (300-1000 ms) for food pictures indexing reduced motivated attention. Affective touch did not influence food cue reactivity (P300/LPP, appetite). Effects of affective touch may be restricted to specific stimuli, e.g. those with social relevance.

Modeling Behavioral Economics Strategies in Social Marketing Messages to Promote Vegetable Consumption to Low-Resource Louisiana Residents: A Conjoint Analysis

BACKGROUND

Behavioral economics strategies implemented within social marketing campaigns improve eating behavior.

OBJECTIVE

To identify which behavioral economics strategies in social marketing messages particularly messengers, norms, and commitments will promote low-income Louisiana residents to add more vegetables to meals.

DESIGN

Full profile traditional conjoint analysis survey with single concept ratings.

PARTICIPANTS

Purposive sample of low-resource Louisiana residents (N = 213) SETTING: Online survey.

INTERVENTION

Participants rated randomized concepts that featured a messenger and a message.

MAIN OUTCOME MEASURE

Ratings (one to nine) of likelihood to add vegetables to meals.

STATISTICAL ANALYSIS

A model of ratings was generated using mixed-effects multiple regression, which accounted for repeated measurement of participants. Interactions of variables and covariates were modeled.

RESULTS

There was a significant main effect of the messenger variable (P = 0.02) and main effect of the message variable (P = 0.008). Pairwise comparisons demonstrated differences between friend (μ (predicted mean) = 6.80) and mother (μ = 7.06; P = 0.03) as well as friend and normal-weight doctor (μ = 7.03; P = 0.04). Pairwise comparisons demonstrated differences between descriptive norm (μ = 6.79) and grocery list precommitment (μ = 7.02; P = 0.05) along with descriptive norm and injunctive norm (μ = 6.98; P = 0.04). Covariate models demonstrated main effects of race (P = 0.006) and sex (P = 0.0001). There was significant variation in the message variable and frequency of vegetable intake interaction (P = 0.01).

CONCLUSIONS

Both message and messenger variables predicted the likelihood to add vegetables to meals. Race and sex influenced ratings to add vegetables. As reported vegetable consumption increased, behavioral economics messages improved the likelihood to add vegetables to meals. Behavioral economic approaches are well suited to social marketing messages that aim to promote healthy eating behavior in low-income LA residents.

Principles and Validations of an Artificial Intelligence-Based Recommender System Suggesting Acceptable Food Changes

BACKGROUND

Along with the popularity of smartphones, artificial intelligence-based personalized suggestions can be seen as promising ways to change eating habits toward more desirable diets.

OBJECTIVES

Two issues raised by such technologies were addressed in this study. The first hypothesis tested is a recommender system based on automatically learning simple association rules between dishes of the same meal that would make it possible to identify plausible substitutions for the consumer. The second hypothesis tested is that for an identical set of dietary-swaps suggestions, the more the user is-or thinks to be-involved in the process of identifying the suggestion, the higher is their probability of accepting the suggestion.

METHODS

Three studies are presented in this article, first, we present the principles of an algorithm to mine plausible substitutions from a large food consumption database. Second, we evaluate the plausibility of these automatically mined suggestions through the results of online tests conducted for a group of 255 adult participants. Afterward, we investigated the persuasiveness of 3 suggestion methods of such recommendations in a population of 27 healthy adult volunteers through a custom designed smartphone application.

RESULTS

The results firstly indicated that a method based on automatic learning of substitution rules between foods performed relatively well identifying plausible swaps suggestions. Regarding the form that should be used to suggest, we found that when users are involved in selecting the most appropriate recommendation for them, the resulting suggestions were more accepted (OR = 3.168; P < 0.0004).

CONCLUSIONS

This work indicates that food recommendation algorithms can gain efficiency by taking into account the consumption context and user engagement in the recommendation process. Further research is warranted to identify nutritionally relevant suggestions.

Modelling population responses to workplace minimum dietary standards introduced as workers return after social lockdowns

BACKGROUND

Diet norms are the shared social behaviours and beliefs about diets. In many societies, including the UK, these norms are typically linked to unhealthy diets and impede efforts to improve food choices. Social interactions that could influence one another's food choices, were highly disrupted during the lockdowns in response to the COVID-19 pandemic. A return to workplaces and re-establishment of eating networks may present an opportunity to influence dietary norms by introducing minimum dietary standards to in workplaces, which could then spread through wider home and workplace networks.

METHODS

An agent-based model was constructed to simulate a society reflecting the structure of a city population (1000 households) to explore changes in personal and social diet-related norms. The model tracked individual meal choices as agents interact in home, work or school settings and recorded changes in diet quality (range 1 to 100). Scenarios were run to compare individuals' diet quality with the introduction of minimum dietary standards with degrees of working from home.

RESULTS

The more people mixed at work the greater the impact of minimum standards on improving diet norms. Socially isolated households remained unaffected by minimum standards, whereas household members exposed directly, in workplaces or schools, or indirectly, influenced by others in the household, had a large and linear increase in diet quality in relation to minimum standards (0.48 [95% CI 0.34, 0.62] per unit increase in minimum standards). Since individuals regressed to the new population mean, a small proportion of diets decreased toward lower population norms. The degree of return to work influenced the rate and magnitude of change cross the population (-2.4 points [-2.40, -2.34] in mean diet quality per 20% of workers isolating).

CONCLUSIONS

These model results illustrate the qualitative impact social connectivity could have on changing diets through interventions. Norms can be changed more in a more connected population, and social interactions spread norms between contexts and amplified the influence of, for example, workplace minimum standards beyond those directly exposed. However, implementation of minimum standards in a single type of setting would not reach the whole population and in some cases may decrease diet quality. Any non-zero standard could yield improvements beyond the immediate adult workforce and this could spill between social contexts, but would be contingent on population connectivity.

Arranging the fruit basket: A computational approach towards a better understanding of adolescents' diet-related social media communications

This study investigated the contents and linguistic styles that adolescents use in their dietary communications on social media. The main aim of the study was to describe adolescents' social media communication practices with regards to diet, in order to better understand dietary social influences and how to effectively intervene in them. The current study made use of an online communication dataset (N = 72,384 messages) of adolescents in primary and secondary school (N = 1038, 9-16 y/o). We analyzed the message content using tailor-made diet- and health-related dictionaries and LDA topic modeling. The linguistic style of the messages was investigated by assessing the sentiment and underlying psychological dimensions. Further, we used multivariate linear regressions to test how each message dimension was related to message liking, which was considered as an indicator of a message's influence potential regarding peers' dietary behaviors. The results confirmed that adolescents show a preference to discuss neutral-to-unhealthy dietary items most often. No association emerged between message content (i.e., message healthiness and topics) and the number of likes that a message received, while messages with more positive sentiment and higher subjectivity received slightly more likes. Also, our findings confirm that visual dietary content is more often liked than textual descriptions alone. The findings indicate that the content and the healthiness of a message does not explain its popularity among adolescents. Rather, the way how diet-related content is formulated (i.e., in a positive and subjective tone) emerged as a more important predictor for message liking.

Extending the Together, We Inspire Smart Eating Curriculum to Intergenerational Nutrition Education: A Pilot Study

The COVID-19 pandemic has made accessing nutritious foods difficult for older adults and children living in low-income households. The evidence-based preschool nutrition education curriculum Together, We Inspire Smart Eating (WISE) can be used to encourage children to try healthy foods. Written as a single generation curriculum, inviting older adult community members to WISE programming for an intergenerational experience may provide further supports and mutual benefits as participants cooperate towards a common goal. While creators have evaluated implementation of WISE, research has yet to explore factors that influence WISE adoption within an intergenerational setting. We conducted a pilot study using the implementation evaluation framework to explore WISE implementation within single generation and intergenerational settings by measuring five implementation outcomes (fidelity, acceptability, appropriateness, feasibility, and sustainability) through three methods: (1) direct assessment of program fidelity via video coding; (2) indirect assessment of stakeholders’ perceptions of WISE implementation, and (3) a directed qualitative content analysis on annual interview data. Fidelity scores were comparable between the two settings and stakeholder ratings of appropriateness, acceptability, and feasibility of WISE were high. Qualitative data revealed that aspects of WISE are less appropriate for older participants and reiterated known logistical barriers of intergenerational programming that may challenge program sustainability.

Development of Novel Eating Error Scoring Tool to Evaluate Adult Eating Behavior Anomalies Among the United Arab Emirates Population

Introduction Maladaptive eating behaviors are emerging as the most significant determinants of obesity with a promising role in intervention. In the absence of a standardized tool to assess eating variations, an Eating Error Score (EES) tool was devised which comprised five zones for evaluating the severity of obesogenic behaviors as well as the specific area(s) with the highest susceptibility. This pilot study was aimed at evaluating the effectiveness of the EES in quantitating the eating behavior errors associated with excess weight and identifying the most affected zones. Methods The EES questionnaire was designed to explore potential disturbances in five zones of eating behavior related to the impetus to eat (Munger), meal choices and attentiveness to cravings (Impulsive), consumption speed (Speed feeding), cues to stop ingestion (Indulgent) and the social aspect of eating (Relationship). The questionnaire was conducted on adults with varying body mass index (BMI) attending governmental outpatient clinics. The correlation between EES and BMI was determined through Pearson Coefficient. Results A total of 204 participants completed the EES questionnaire. There were 72 males and 132 females with a mean BMI of 27.63 ± 6.16 kg/m2 and with nearly equal distribution between normal weight (37.2%), overweight (32.4%), and obese (29.4%) individuals. Nearly 75% of our cohort had a moderate total EES, and the remainder was equally distributed between the mild and severe ranges. A weak but significant correlation was observed between total EES and BMI (r=0.275, p<0.001) suggesting increasing obesogenic styles in participants with excess weight. In addition, a similar weak but significant correlation was noted between Body Mass Index and the Munger and Impulsive zones (r=0.266 and 0.258 and p<0.001, respectively) suggesting more severe maladaptive eating behaviors in these areas. No correlation was found with the Speed feeding, Indulgent, and Relationship zones. Conclusion The EES may be a useful tool for assessing the extent of maladaptive eating behaviors, which predispose individuals to weight gain and sabotage their weight loss efforts. Undoubtedly, the utility of the tool needs to be corroborated in large population studies. Further, identifying the specific operant zones may show promise as many of these habits are potentially modifiable and can be targeted for weight control, most notably those associated with the Munger and Impulsive zones.

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.

Testing the relationship between inhibitory control and soda consumption: An event-related potential (ERP) study

The intake of sugar-sweetened beverages (SSB) may detrimentally influence health outcomes. Drinking less soda may help manage SSB consumption, as soft drinks are a top contributor to SSB intake. One cognitive factor that may influence soda consumption is inhibitory control, or the ability to withhold a dominant response in order to correctly respond to one's environment. Increased inhibitory control plays a role in decreasing consumption of high-calorie foods, and strengthening inhibitory control may help individuals manage their food intake. However, neural response to soda beverages versus traditional non-sweetened beverages, such as water, and how it relates to soda consumption is unknown. In a sample of 116 healthy individuals (M = 20.56; SD = 2.08; 47.4% female), we measured soda consumption and tested event-related potential (ERP) measures of inhibitory control, including the N2 and P3 components, during soda-specific and neutral comparison go/no-go tasks. Female participants consumed less soda on average than males, and as participants got older, they consumed less soda. Participants showed faster response times and higher accuracy on the soda-specific compared to neutral go/no-go . ERP results indicated inhibitory control was greater when individuals withheld dominant responses to soda stimuli rather than neutral stimuli. Neither N2 no-go amplitude on the soda-specific go/no-go nor P3 no-go amplitude on the soda-specific predicted measures of soda intake. Results suggest greater inhibitory control resources are required when withholding responses to soda beverages compared to neutral stimuli, but inhibitory control ERPs did not predict day-to-day soda intake.

The influence of experimental confederate peers on children's food intake: A systematic review and meta-analysis

Confederates influence eating behaviour. Systematic reviews and meta-analyses have been conducted on this topic, however, the majority have examined adults, or a combination of adults and children, therefore, an up-to-date meta-analysis is needed to examine the impact of confederate peers on children's food intake. We systematically reviewed and meta-analysed the influence of confederate peers on children's food intake in research using present and remote-confederates. Six publications summarising findings from seven studies were included in this review. One publication was excluded from the meta-analysis because it was not possible to extract the required data. The meta-analysis showed that children were influenced by confederate peers; eating more when exposed to a high-intake compared to a no or low-intake confederate. Larger effects were observed when children were exposed to a remote-than a present-confederate, and for studies using healthy snacks compared to high fat high sugar (HFHS) snacks. No difference in effect size was observed when children were exposed to a high-vs. low-intake confederate compared to a high-vs. no-intake confederate. In the narrative synthesis, confederate intake influenced children's eating behaviour 24-h later, and possible moderators and a potential mechanism underlying the influence of confederates were identified. Caution is needed when interpreting the results, as the sub-groups were not compared statistically due to high heterogeneity, and a small number of studies were included in this review. Furthermore, all studies using the present-confederate design examined HFHS snack intake, therefore, it is unclear whether observed differences in effect sizes between present- and remote-confederates may be due to confederate or food type. Research is needed to further examine the influence of confederate peers on children's food intake and to examine mechanisms and moderators.

Associations between Perceived Social Eating Norms and Initiation and Maintenance of Changes in Dietary Habits during the First COVID-19 Lockdown in France

Changes in dietary habits of the French population have been reported during the national lockdown that was enforced due to the COVID-19 pandemic. This study investigated whether perceived social eating norms were associated with the initiation and maintenance of dietary changes that took place as a result of lockdown. An online study collected information on (1) changes in consumption implemented during the lockdown and the maintenance of these changes, and (2) perceptions about changes in consumption implemented during lockdown by household members, relatives out of home, and the general population. The changes in consumption were classified as foods to increase or to decrease according to French national recommendations. The perception of changes to dietary habits by household members and relatives out of home was related to the changes made by individuals for each of the food categories (all p < 0.05) but not to the perception of changes made the general population. Increased consumption of foods to increase was more likely to be maintained when there was a positive perception of the changes made by household members (p = 0.03). These results highlight the influence of the perception of social eating norms, especially by household members and relatives, on the implementation of dietary changes during lockdown and suggest that social eating norms can have a lasting influence.

Can Social Cognitive Theory Influence Breakfast Frequency in an Institutional Context: A Qualitative Study

Breakfast is considered an important meal, especially for people who are about to commence a long or demanding workday, and for roles that may involve physical tasks and a requirement to remain alert and vigilant in potentially high-risk situations. This study looks at breakfast consumption influences within two workplace institutional settings, namely military and mining. Semi-structured interviews were conducted with military personnel (n = 12) and mining employees (n = 12) to understand their breakfast consumption behaviour at work and at home, and the associated behavioural influences. The interview questions were framed by social cognitive theory. Overall, cognitive and environmental influences were the most prominent influences on breakfast consumption, less evident were behavioural influences. A negative stereotype of workplace institutional food services emerged as one of the most significant barriers to breakfast consumption for those already at work. Considerations of environmental influences on behaviour may need to be broadened beyond physical barriers and social influences, to include perceptions of the behavioural environment. Programs that aim to increase breakfast consumption must create areas where their employees want to go. Food systems need to ensure nutritious, quality, and appealing food is available. Interventions need to increase participants’ knowledge, improve their attitudes, and create positive expectations for breakfast.

Social reward from giving food to others affects food craving and brain potentials: An imagery-based event-related potential study

The interactions between social and eating behaviors can be quite pronounced and are mediated by overlapping neural circuits. The present event-related potential study tested whether the imagery of a specific prosocial behavior (giving chocolates to grateful children) can influence food cue reactivity. A total of 92 females (mean age = 23.5 years) were randomly assigned to one of three guided imagery conditions. The participants listened to an audio recording and were instructed to imagine one of three possible scenes; giving 30 M&Ms to children, eating 30 M&Ms, or sorting 30 marbles. Directly after the imagery task, the participants were presented with images of M&Ms and marbles while their electroencephalogram was recorded. We examined the Late Positive Potential (LPP) across a fronto-central and a parieto-occipital cluster, M&M craving, and subsequent consumption of (real) M&Ms. The mental imagery of offering M&Ms to children was associated with lower M&M craving and higher fronto-central LPP amplitudes (300-600 ms after picture onset) compared to the other imagery conditions. The consumption of M&Ms did not differ between the groups. The LPP is sensitive to the implementation of craving regulation strategies. Furthermore, heightened LPPs are reliably observed in response to motivationally significant stimuli, conflict, and social context. Future studies are needed to specify the specific psychological processes that are associated with the observed LPP effect. In conclusion, this study demonstrated that mental imagery of receiving a social reward from giving food to others can change components of food cue reactivity in healthy females.

Watching a remote-video confederate eating facilitates perceived taste and consumption of food

People eat more when their eating confederates eat a lot. However, it was not clear whether participants' eating is changed by a remote-video confederate. We compared three types of silent videos: 1) a stranger eating potato chips, 2) the stranger calling on the phone, or 3) only objects (food and cellphone). Participants perceived popcorn to taste better only when they watched the video of others eating. Watching others eating induced the participants to eat more than when watching the other two videos. This study indicates that remote-video confederates enhance not only food intake but also the perceived taste of food.

The Relationship between Music and Food Intake: A Systematic Review and Meta-Analysis

Food intake has been shown to be related to several environmental factors including the presence of music. However, previous findings of the relationship between music and food intake are inconsistent. In the present study, a systematic review and meta-analysis was conducted to quantitatively review the extent to which music is associated with food intake as well as to investigate potential moderators that might have contributed to the heterogeneity of the existing findings. Literature was searched on four databases (i.e., PsycINFO, Web of Science, PubMed, and ProQuest Dissertations and Theses) and Google Scholar. Nine articles published from 1989 to 2020 met our inclusion criteria. A meta-analysis was carried out via a three-level random-effects model. The overall effect size (i.e., Hedges' g) was 0.19 (95% Confidence Interval: -0.003, 0.386; SE = 0.10, t = 1.99, p = 0.054), indicating a marginally significant but small effect size. Body Mass Index (F(1, 21) = 5.11, p = 0.035) was found to significantly contribute to the heterogeneity of effect sizes, with larger positive effects of music on food intake for individuals with higher BMI. However, music-related features did not significantly moderate the relationship between music and food intake. More experimental studies are needed to update the current meta-analysis and get a better understanding of this topic.

Resources in women's social networks for food shopping are more strongly associated with better dietary quality than people: A cross-sectional study

When healthy people are part of an individual's social network, those individuals will have better dietary quality. Little, however, is known about whether social networks for food shopping, including both people and resources (e.g. recipes, weight loss programmes and food advertisements) are associated with dietary quality. The aim of this study was to explore the relationship between social networks for food shopping and dietary quality, and whether this differs for people and resources, among women aged 18-45 years. A total of 129 participants completed a cross-sectional questionnaire including an ego-centric Social Network Exposure tool and short Food Frequency Questionnaire. Associations between dietary quality and type of network member, perceived healthiness and support for healthy shopping choices were explored using linear regression models. Analyses revealed that participants who nominated people in their food shopping social network that eat healthily or support healthy food shopping had better dietary quality (β = 0.16 SD per 1-point change on a 4-point scale, 95%CI -0.06, 0.39; β = 0.20, 95%CI -0.07, 0.46, respectively). Resources in participants' food shopping social networks which promote healthy eating or support healthy shopping were associated with better dietary quality. These associations remained robust after adjustment for confounding variables identified using a directed acyclic graph (β = 0.31 SD per 1-point change on a 4-point scale, 95%CI 0.03, 0.58; β = 0.44, 95%CI 0.09, 0.79 respectively). The results were strengthened when the outcome was multiplied by frequency of contact (β = 0.33, 95%CI 0.05, 0.61; β = 0.47, 95%CI 0.11, 0.83 respectively). This study suggests that resources which promote healthy eating and healthy food shopping have a stronger association with dietary quality than social support from people. Further research is required in a larger sample, including multiple time-points, to confirm these findings.

What Is Commensality? A Critical Discussion of an Expanding Research Field

Commensality (the act of eating together) is studied in a range of disciplines and often considered important for social communion, order, health and well-being, while simultaneously being understood as in decline (especially the family meal). However, such claims are also contested in various ways. In this paper, we discuss the expanding field of commensality research and critically reflect on the debates surrounding its social functions, including its role in public health. We illuminate the deep social and cultural significance of commensality, through time and space, and conclude that whether or not commensality is the preferred social form of eating for any given individual, it is difficult to escape its sociocultural desirability and idealization. As a cross-cultural phenomenon in both past, present, and future, we suggest that commensality deserves further research. This includes commensality as a research topic in itself and as an entry point to unveil different dimensions of social relations between people, as well as interactions between humans and material objects.

Social Modeling and Eating Behavior-A Narrative Review

Social modeling of eating is the adjustment of the amount of food eaten to the intake of the accompanying person. In this paper we provide a narrative review of literature on social modeling of eating with a particular focus on recent studies. Firstly, we describe the structure of a typical modeling experiment. Secondly, we present a variety of research in this field: experiments with various types of confederates, experiments aimed at the evaluation of the influence of gender, partner’s body weight, type of food, hunger, personal characteristics, etc. Thirdly, we present practical implications of this knowledge. The common conclusion is that social modeling of eating occurs in different situations and consumption is adapted to the standards established by the eating partner, but is not their direct reflection. Social influence of eating is not restricted to "artificial" laboratory situations; social modeling and social norms manipulations may be used to change people’s dietary practices, especially in children and young adults. Within the home environment parental modeling has been shown to promote children’s snacking and fruit and vegetable consumption. Social modeling may be used in nutrition interventions aimed at the improvement of children’s diet and in obesity prevention programs.

Social modeling of food choices in real life conditions concerns specific food categories

The social context of eating has a profound effect on consumption choices. Social modeling, that involves using others' behavior as a guide for appropriate consumption, has been well documented for food intake, but less is known about social modeling of food choices. Moreover, social modeling has mainly been studied in laboratory settings. We conducted an observational study in a self-service canteen to examine whether the food choices of an individual were influenced by the choice of the person ahead in the queue. We recorded food choices of 546 individuals (333 men and 211 women) and those of the person in front of them in the queue along a linear buffet. Starters were sub-categorized into salads, mixed starters (e.g. avocado shrimp mayonnaise), and cold meat starters, and desserts were sub-categorized into fruits, dairy products and pastries. There was a significantly higher probability of taking a starter in general (OR = 1.65, IC = 1.06-2.57, p = 0.03), a salad (OR = 1.78, CI = 1.08-2.93, p = 0.02), a mixed starter (OR = 2.98, CI = 1.42-6.05, p < 0.01), but not a cold meat, if the person ahead in the queue also took one compared to when the person ahead did not take one. No significant modelling was found for desserts which may be because almost all participants took a dessert. These results highlight that social modeling influences food choices, and that this phenomenon can be observed in a real life setting. These data also suggest that some food categories, such as starters, could be more susceptible to social modeling than are others. Finally, we observed modeling both between familiar and unfamiliar participants, which suggests that social norms could be used to promote healthier eating in a range of settings including friendship groups.

Eating self-efficacy: validation of a new brief scale

PURPOSE

Eating self-efficacy (ESE) is the belief in one's ability to self-regulate eating. Social and emotional situations may be differently challenging depending on the individual eating habits, body mass index and affects. Several ESE scales have been developed but most of them focus on weight management, dieting or healthy eating. The aim of the study was to validate a new brief scale assessing ESE in situations in which people face social or emotional pressures for excessive food intake.

METHODS

Study 1: A sample of 412 volunteer females (age M = 25.44 ± 5.03) completed a first 25-item version of the scale. Exploratory factor analysis (EFA) was conducted for selecting a subgroup of items composing the ESE brief scale (ESEBS). Study 2 assessed its psychometric properties through a Confirmatory Factor Analysis (CFA), analyzing the responses of 410 volunteer adults (273 females, 137 males).

RESULTS

EFA of Study 1 evidenced a bifactorial structure. Four items for each factor were selected, explaining 63% of the variance. Study 2 confirmed the good fit of the bifactorial model (CFI = 0.9589; χ² (19) = 62.852, p < 0.001; RMSEA = 0.075; SRMR = 0.040) and provided support for the measurement invariance of the scale across gender. The internal consistency was as follows: Social (α = 0.786), Emotional (α = 0.820). The concurrent validity of the subscales was demonstrated by significant latent negative correlations with measures of eating disorders and emotional eating.

CONCLUSIONS

The 8-items ESEBS appears as a valid and reliable instrument to assess eating self-efficacy related to social and emotional situations. Future studies should evaluate its potential use in non-clinical and clinical research and interventions.

LEVEL OF EVIDENCE

Level V, descriptive cross-sectional study.

A nudge in the right direction: the role of food choice architecture in changing populations' diets

Populations' diets typically fall short of recommendations. The implication of this on ill health and quality of life is well established, as are the subsequent health care costs. An area of growing interest within public health nutrition is food choice architecture; how a food choice is framed and its influence on subsequent food selection. In particular, there is an appeal to manipulating the choice architecture in order to nudge individuals' food choice. This review outlines the current understanding of food choice architecture, theoretical background to nudging and the evidence on the effectiveness of nudge strategies, as well as their design and implementation. Interventions emphasising the role of nudge strategies have investigated changes to the accessibility, availability and presentation of food and the use of prompts. Empirical studies have been conducted in laboratories, online and in real-world food settings, and with different populations. Evidence on the effectiveness of nudge strategies in shifting food choice is encouraging. Underpinning mechanisms, not yet fully explicated, are proposed to relate to salience, social norms and the principle of least effort. Emerging evidence points to areas for development including the effectiveness of choice architecture interventions with different and diverse populations, and the combined effect of multiple nudges. This, alongside further examination of theoretical mechanisms and guidance to engage and inspire across the breadth of food provision, is critical. In this way, the potential of choice architecture to effect meaningful change in populations' diets will be realised.

Modeling of food intake among restrained and unrestrained eaters

The Theory of Normal Eating suggests that how much others eat sets an upper limit for how much it is appropriate to eat. This study tested the hypothesis that restrained eaters, who typically eat less than they want to, would be more responsive to a high-intake norm than would unrestrained eaters. Data were combined from 8 experimental studies (total N = 735 female participants; 305 restrained eaters, 430 unrestrained eaters). Each study: (a) included a low-intake norm, a high-intake norm, and a no-norm control condition; (b) measured participants' food intake; and (c) included the Restraint Scale as a measure of dietary restraint. There were no differences between restrained unrestrained eaters in the no-norm control condition or in the magnitude of the inhibition effect (i.e., the difference between the low-intake norm condition and the control condition). There was, however, a restraint difference in the magnitude of the augmentation effect (i.e., the difference between the high-intake norm condition and the control condition). Restrained eaters showed a larger augmentation effect (d = 0.58; 95% CI = 0.29, 0.87) than did unrestrained eaters (d = 0.20; 95% CI = -0.05, 0.45). Social norms provide an upper limit for acceptable food intake, with high-intake norms permitting (but not requiring) individuals to indulge themselves. The fact that restrained eaters were more responsive to the high-intake norm than were unrestrained eaters suggests that the high-intake norm gives restrained eaters permission to indulge when they typically eat less than they want to.

Siblings of Individuals With Eating Disorders: A Review of the Literature

Eating disorders (EDs) are serious psychopathologies characterized by a persistent disturbance in eating or eating-related behavior. Studies have shown EDs' detrimental consequences not only for patients, but also for their families. Nevertheless, a specific group that has so far been neglected, in both the research and clinical fields, are siblings of individuals with EDs. In an effort to identify this population's needs, and to facilitate effective prevention and treatment, this paper aims to review the existing literature on the subject, and examine siblings' personal experience, ways of coping, and levels of psychopathology. PubMed and PsycNet databases were searched with no publication date restrictions, yielding 26 relevant papers. Studies were categorized according to common themes they addressed, and subsequently summarized by highlighting common features, as well as information unique to each study. Several themes emerged, including emotional well-being, psychopathology, social consequences, family dynamics, and coping strategies. Results show that EDs experienced by one individual have significant effects on one's siblings, such as a decrease in quality of life, social isolation, and elevated familial strain. In several studies siblings were found to have elevated levels of psychopathology and EDs related symptoms. Nevertheless, findings' nature and magnitude were highly varied. The review indicates the need for further studies that will examine possible intra- and interpersonal moderating factors for EDs' impact on well-being among siblings, and take into consideration the substantial heterogeneity in studies conducted thus far. Additionally, this review highlights the need for novel and effective interventions, specifically targeting this at-risk group.

Behaviour change during dietary Type 2 diabetes remission: a longitudinal qualitative evaluation of an intervention using a very low energy diet

AIM

To understand the process of behaviour change through the experiences of people with Type 2 diabetes engaged in an 8-month diabetes remission intervention including a 2-month weight loss phase with the use of a very low energy diet (VLED), and a 6-month, structured weight maintenance phase.

METHODS

Data were collected in three semi-structured interviews at baseline, week 8 (end of the weight loss phase), and month 8 (end of the weight maintenance phase). Longitudinal inductive thematic analysis was used to analyse participants' narratives and identify change over time.

RESULTS

Eleven of 18 participants completed all three interviews. The following themes of change were identified in their narratives: (1) 'Building behavioural autonomy' as a process of growing confidence to engage in health behaviours that are independent of those of other people; (2) 'Behavioural contagion' describing how one's new health behaviours tend to affect those of other people; (3) 'From rigid to flexible restraint', reflecting the changes in attitudes and behaviours required for a successful adaptation from weight loss to weight maintenance; and (4) 'Shift in identity', representing changes in the participants' perceptions of themselves.

CONCLUSIONS

This longitudinal qualitative study provided new insights into how behaviour change is experienced by people with Type 2 diabetes engaged on a weight management intervention using VLED, contributing to theoretical and practical understanding of weight management behaviours. The themes identify potential areas in which individuals can be supported in achieving dietary diabetes remission and long-term maintenance of weight loss.

Gender norms and social norms: differences, similarities and why they matter in prevention science

Two streams of theory and practice on gender equity have begun to elide. The first is work conducted to change social norms, particularly using theory that emerged from studies in social psychology. The second is work done on gender norms, emerging historically from feminist scholars working to counter gender inequality. As these two streams of work intersect, conceptual clarity is needed to understand differences and similarities between these two traditions. Increased clarity will improve efforts to address harmful norms and practices. In this article, we review similarities and differences between social and gender norms, reviewing the history of the concepts and identifying key tension points of contrast. We identified six areas of comparison that might be helpful for practitioners working for the promotion of global health as they make sense of social and gender norms. We then offer a definition of gender norms for practitioners and researchers working at the intersection between these two theories. Our definition draws from the two different streams of thought of how norms influence people's actions, acknowledging the double nature of gender norms: beliefs nested in people's minds and embedded in institutions that profoundly affect health-related behaviours and shape differential access to health services.

Office cake culture

Purpose

The purpose of this paper is to explore the characteristics of office cake (OC) consumption and the associated attitudes and behaviours among UK office workers to gain insight into the implications for workplace health.

Design/methodology/approach

A cross-sectional online questionnaire was completed by 940 respondents. Data were analysed using descriptive statistics and cross-tabulation withχ2tests for between-group difference.

Findings

Respondents reported both positive social and negative health-related consequences of OC. OC influenced eating behaviour through increased salience and availability, and the effects of social influencing. Almost all (94.8 per cent) reported ideal OC frequency to be once/week or less. Gender and age significantly affected attitudes and behaviour.

Research limitations/implications

The questionnaire was not validated so data accuracy could have been diminished or biased. Portion size was not examined and consumption data were self-reported which could have resulted in under-reporting. Only office workers were investigated therefore results may not be applicable to other workplaces.

Practical implications

OC appears to influence both the workplace eating environment and employee eating behaviour. It could therefore affect employee health and workplace health promotion programme efficacy. However the findings suggest that nudge-based initiatives could reduce OC consumption to make workplaces healthier while retaining social benefits.

Originality/value

The present study provides the first data on OC culture and insights on how to address it sensitively. It also highlights that sweet treats used for celebration and employee recognition should be considered a relevant part of workplace food provision alongside canteens and vending.

A systematic review and meta-analysis of the social facilitation of eating

BACKGROUND

Research suggests that people tend to eat more when eating with other people, compared with when they eat alone, and this is known as the social facilitation of eating. However, little is known about when and why this phenomenon occurs.

OBJECTIVES

This review aimed to quantify the evidence for social facilitation of eating and identify moderating factors and underlying mechanisms.

METHODS

We systematically reviewed studies that used experimental and nonexperimental approaches to examine food intake/food choice as a function of the number of co-eaters. The following databases were searched during April 2019: PsychInfo, Embase, Medline, and Social Sciences Citation Index. Studies that used naturalistic techniques were narratively synthesized, and meta-analyses were conducted to synthesize results from experimental studies.

RESULTS

We reviewed 42 studies. We found strong evidence that people select and eat more when eating with friends, compared with when they eat alone [Z = 5.32; P < 0.001; standardized mean difference (SMD) = 0.76; 95% CI: 0.48, 1.03]. The meta-analysis revealed no evidence for social facilitation across studies that had examined food intake when participants ate alone or with strangers/acquaintances (Z = 1.32; P = 0.19; SMD = 0.21, 95% CI: -0.10, 0.51). There was some evidence that the social facilitation of eating is moderated by gender, weight status, and food type. However, this evidence was limited by a lack of experimental research examining the moderating effect of these factors on the social facilitation of eating among friends. In 2 studies, there was evidence that the effect of the social context on eating may be partly mediated by longer meal durations and the perceived appropriateness of eating.

CONCLUSIONS

Findings suggest that eating with others increases food intake relative to eating alone, and this is moderated by the familiarity of co-eaters. The review identifies potential mechanisms for the social facilitation of eating and highlights the need for further research to establish mediating factors. Finally, we propose a new theoretical framework in which we suggest that the social facilitation of eating has evolved as an efficient evolutionary adaptation.

The effectiveness of a social media intervention for reducing portion sizes in young adults and adolescents

Objective

Adolescents 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.

Methods

Two 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.

Results

In 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.

Conclusions

These 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.

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.

Advertising models in the act of eating: How the depiction of different eating phases affects consumption desire and behavior

In print advertising, the use of static pictures depicting models eating food is common practice. However, less is known about how the depiction of models in different phases of consumption (holding food, moving food to mouth, taking a bite, chewing on food) affects consumers. Theories have proposed that not only do individuals mimic actions, but they also adopt the goals and the motivational patterns underlying these actions by observing others. Building on this view, we hypothesized that consumers' desire to eat a food product and their actual consumption of a food product would be greater when the model in the picture was close to engaging in consumption and that desire and actual consumption would be reduced when the model was shown in the process of finishing consumption. In two studies, we found that the participants experienced an increased desire to eat the depicted food (Study 1) and ate more of the advertised food (Study 2) when the model was shown to engage in eating food compared with when the model was shown during completion of a consumption episode. In addition, the results of Study 1 suggest that even subtle differences such as holding food compared with putting food into the mouth might affect consumers' desire to eat. Overall, our results suggest that advertisements may affect consumers' motivation to engage in food intake differently depending on which consumption state they show with the depiction of a model close to engagement in food consumption being most likely to trigger a desire for consumption and an actual engagement in food intake.

Correlation and temporal variability of urinary biomarkers of chemicals among couples: Implications for reproductive epidemiological studies

BACKGROUND

Exposure to some environmental chemicals is ubiquitous and linked to a variety of adverse outcomes, including children's health. While few studies have assessed the contribution of both male and female exposures to children's health, understanding the patterns of couple's exposure is needed to understand their joint effects.

OBJECTIVE

We assessed the correlation patterns between male and female partners' concentrations of 37 environmental chemical biomarkers. We also assessed the temporal reliability of the biomarkers within couples.

METHODS

We calculated Spearman pairwise correlations between specific gravity adjusted urinary biomarker concentrations and hair mercury concentrations among 380 couples enrolled in the Environment and Reproductive Health (EARTH) study at the Massachusetts General Hospital Fertility Center (2004-2017). We calculated intra-class correlation coefficients (ICCs) for couple's biomarkers to assess the temporal variability of these exposures within a couple using multiple paired-samples from couples.

RESULTS

All biomarkers were positively correlated within couples (range: 0.05 for tert-butylphenyl phenyl phosphate to 0.66 for triclosan). In general, the biomarkers with the highest within couple correlation were those of chemicals for which diet (e.g., di(2-ethylhexyl) phthalate), personal care products use (e.g., triclosan, benzophenone-3), and the indoor environment (e.g., 2,5-dichlorophenol) are considered primary exposure sources. Most other biomarkers were moderately correlated (0.3-<0.6). Similar patterns of temporal reliability were observed across biomarkers.

CONCLUSIONS

Urinary concentrations of several biomarkers were mostly moderately correlated within couples, suggesting similar exposure sources. Future epidemiological studies should collect samples from both partners to be able to accurately determine the contribution of maternal and paternal exposures to offspring health.

Two observational studies examining the effect of a social norm and a health message on the purchase of vegetables in student canteen settings

There is some evidence from laboratory-based studies that descriptive social-norm messages are associated with increased consumption of vegetables, but evidence of their effectiveness in real-world settings is limited. In two observational field studies taking an ecological approach, a vegetable-related social norm (e.g. "Did you know that most students here choose to eat vegetables with their meal?"), and a health message (e.g. "Did you know that students who choose to eat vegetables have a lower risk of heart disease?") were displayed in two different student canteens. Purchases were observed during three stages: baseline, intervention (when the posters were displayed) and immediate post-intervention (when the posters had been removed). Study 1 (n = 7598) observed the purchase of meals containing a portion of vegetables and Study 2 (n = 4052) observed the purchase of side portions of vegetables. In Study 1, relative to baseline, the social-norms intervention was associated with an increase in purchases of vegetables (from 63% to 68% of meals; OR = 1.24, CI = 1.03-1.49), which was sustained post-intervention (67% of meals; OR = 0.96, CI = 0.80-1.15). There was no effect of the health message (75% of meals at baseline, and 74% during the intervention; OR = 0.98, CI = 0.83-1.15). In Study 2, relative to baseline, there was an effect of both the social norm (22.9% of meals at baseline, rising to 32.5% during the intervention; OR = 1.62, CI = 1.27-2.05) and health message (rising from 43.8% at baseline to 52.8%; OR = 0.59, CI = 0.46-0.75). The increase was not sustained post-intervention for the social norm intervention (22.1%; OR = 0.59, CI = 0.46-0.75), but was sustained for the health intervention (48.1%; OR = 0.83, CI = 0.67-1.02). These results support further testing of the effectiveness of such messages in encouraging healthier eating and indicate the need for larger-scale testing at multiple sites using a randomised-controlled design.

Contextual correlates of energy-dense snack food and sweetened beverage intake across the day in African American women: An application of ecological momentary assessment

This study examined relationships between contextual factors and within-person variations in snack food and sweetened beverage intake in African American women (n = 79), aged 25-65 years living in metropolitan Chicago. For seven days, participants wore a global positioning system (GPS) logger and were signaled five times per day to complete an ecological momentary assessment (EMA) survey assessing behaviors and environmental, social, and other contextual factors via smartphones. Within-person associations between snack food and beverage intake and contextual factors were analyzed using three-level logistic regressions. Participants reported consuming a snack food at 38.4% of signals and a sweetened beverage at 17.9% of signals. Fast food restaurant and convenience store density within the daily activity space was not associated with either snack food or sweetened beverage intake. However, perceptions of close proximity to fast food restaurants and convenience stores making it easier to eat/drink, while accounting for one's usual proximity, were associated with increased odds of snack intake (O.R. 2.1; 95% C.I. 1.4, 3.0) but not sweetened beverage. We also found engaging in activities such as watching television (O.R. 1.8; 95% C.I. 1.2, 2.7) and talking (O.R. 1.7; 95% C.I. 1.1, 2.6) while eating were associated with higher snack intake. These factors were not related to sweetened beverage intake. Public health interventions addressing fast food restaurant and convenience store accessibility and food offerings and marketing within these outlets may help reduce snack food intake. Additionally, to reduce concurrent activities while eating, real-time interventions using smart technology could be used to enhance attentive eating in this population.

Theory and practice of social norms interventions: eight common pitfalls

BACKGROUND

Recently, Global Health practitioners, scholars, and donors have expressed increased interest in "changing social norms" as a strategy to promote health and well-being in low and mid-income countries (LMIC). Despite this burgeoning interest, the ability of practitioners to use social norm theory to inform health interventions varies widely.

MAIN BODY

Here, we identify eight pitfalls that practitioners must avoid as they plan to integrate a social norms perspective in their interventions, as well as eight learnings. These learnings are: 1) Social norms and attitudes are different; 2) Social norms and attitudes can coincide; 3) Protective norms can offer important resources for achieving effective social improvement in people's health-related practices; 4) Harmful practices are sustained by a matrix of factors that need to be understood in their interactions; 5) The prevalence of a norm is not necessarily a sign of its strength; 6) Social norms can exert both direct and indirect influence; 7) Publicising the prevalence of a harmful practice can make things worse; 8) People-led social norm change is both the right and the smart thing to do.

CONCLUSIONS

As the understanding of how norms evolve in LMIC advances, practitioners will develop greater understanding of what works to help people lead change in harmful norms within their contexts. Awareness of these pitfalls has helped several of them increase the effectiveness of their interventions addressing social norms in the field. We are confident that others will benefit from these reflections as well.