Neural response to fast food commercials in adolescents predicts intake

The association between obesity severity and food reward in adolescents with obesity: a one-stage individual participant data meta-analysis

BACKGROUND

Food reward and cue reactivity have been linked prospectively to problematic eating behaviours and excess weight gain in adults and children. However, evidence to date in support of an association between degree of adiposity and food reward is tenuous. A non-linear relationship between reward sensitivity and obesity degree has been previously proposed, suggesting a peak is reached in mild obesity and decreases in more severe obesity in a quadratic fashion.

OBJECTIVE

To investigate and characterise in detail the relationship between obesity severity, body composition, and explicit and implicit food reward in adolescents with obesity.

METHODS

Data from seven clinical trials in adolescents with obesity were aggregated and analysed in an independent participant data meta-analysis. Linear and curvilinear relationships between the degree of obesity and explicit and implicit reward for sweet and high fat foods were tested in fasted and fed states with BMI-z score as a continuous and discrete predictor using clinically recognised partitions.

RESULTS

Although positive associations between obesity severity and preference for high-fat (i.e. energy dense) foods were observed when fasted, none reached significance in either analysis. Conversely, adiposity was reliably associated with lower reward for sweet, particularly when measured as implicit wanting (p = 0.012, ηp2 = 0.06), independent of metabolic state. However, this significant association was only observed in the linear model. Fat distribution was consistently associated with explicit and implicit preference for high-fat foods.

CONCLUSIONS

A limited relationship was demonstrated between obesity severity and food reward in adolescents, although a lower preference for sweet could be a signal of severe obesity in a linear trend. Obesity is likely a heterogenous condition associated with multiple potential phenotypes, which metrics of body composition may help define.

CLINICAL TRIAL REGISTRATIONS

NCT02925572: https://classic.

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gov/ct2/show/NCT02925572 . NCT03807609: https://classic.

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gov/ct2/show/NCT03807609 . NCT03742622: https://classic.

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gov/ct2/show/NCT03742622 . NCT03967782: https://classic.

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gov/ct2/show/NCT03968458 . NCT04739189: https://classic.

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gov/ct2/show/NCT04739189 . NCT05365685: https://www.

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More than a Nuisance: Implications of Food Marketing for Public Health Efforts to Curb Childhood Obesity

Fifteen years ago, public health experts urged industry, governments, and advocates to take action to dramatically improve the unhealthy food-marketing environment surrounding children in order to address the global childhood obesity crisis. Since then, research has confirmed that food marketing to children has far-reaching negative effects on their diets and health, takes advantage of adolescent vulnerabilities, and contributes to health disparities. In addition, digital marketing has profoundly changed young people's engagement with brands. Moreover, reliance on industry self-regulation as a solution has proven ineffective. Government-led policies have been more successful, but they remain limited in scope and challenging to adopt and implement. New approaches are necessary to increase public and policy maker awareness that food marketing is more than a nuisance, that it threatens the long-term health of children and adolescents worldwide, and that meaningful governmental action is urgently required to curtail industry's negative impact on young people's well-being.

Associations between maternal pre-pregnancy BMI and infant striatal mean diffusivity

BACKGROUND

It is well-established that parental obesity is a strong risk factor for offspring obesity. Further, a converging body of evidence now suggests that maternal weight profiles may affect the developing offspring's brain in a manner that confers future obesity risk. Here, we investigated how pre-pregnancy maternal weight status influences the reward-related striatal areas of the offspring's brain during in utero development.

METHODS

We used diffusion tensor imaging to quantify the microstructure of the striatal brain regions of interest in neonates (N = 116 [66 males, 50 females], mean gestational weeks at birth [39.88], SD = 1.14; at scan [43.56], SD = 1.05). Linear regression was used to test the associations between maternal pre-pregnancy body mass index (BMI) and infant striatal mean diffusivity.

RESULTS

High maternal pre-pregnancy BMI was associated with higher mean MD values in the infant's left caudate nucleus. Results remained unchanged after the adjustment for covariates.

CONCLUSIONS

In utero exposure to maternal adiposity might have a growth-impairing impact on the mean diffusivity of the infant's left caudate nucleus. Considering the involvement of the caudate nucleus in regulating eating behavior and food-related reward processing later in life, this finding calls for further investigations to define the prognostic relevance of early-life caudate nucleus development and weight trajectories of the offspring.

Food and non-alcoholic beverage marketing in children and adults: A systematic review and activation likelihood estimation meta-analysis of functional magnetic resonance imaging studies

Food marketing impacts the food behaviors of children and adults, but the underpinning neural mechanisms are poorly understood. This systematic review and meta-analysis pooled evidence from neuroimaging studies of exposure to food marketing stimuli (vs. control) on brain activations in children and adults to clarify regions associated with responding. Databases were searched for articles published to March 2022. Inclusion criteria included human functional magnetic resonance imaging (fMRI) studies employing a contrast between a food marketing stimulus and a non-food/non-exposure control, published in English in a peer-reviewed journal, reporting whole brain (not Region of Interest [ROI] only) co-ordinates. Eleven studies met inclusion criteria, of which eight were included in the quantitative synthesis (Activation Likelihood Estimation [ALE] meta-analysis). Food marketing exposures (vs. controls) produced greater activation in two clusters lying across the middle occipital gyrus, lingual gyrus, and cuneus (cluster 1), and the postcentral gyrus, precentral gyrus, and the inferior parietal lobule/supramarginal gyrus (cluster 2). Brain responses to food marketing are most consistently observed in areas relating to visual processing, attention, sensorimotor activity, and emotional processing. Subgroup analyses (e.g., adults vs. children) were not possible because of the paucity of data, and sensitivity analyses highlighted some instability in the clusters; therefore, conclusions remain tentative pending further research.

Applying psycho-behavioural phenotyping in obesity characterization

Individual differences in obesity, beyond being explained by metabolic and medical complications, are understood by alterations in eating behaviour which underlie psychological processes. From this psychological perspective, studies have identified several potential characteristic features at the psycho-behavioural level that could additionally explain the maintenance of chronic excess weight or the unsuccessful results of current treatments. To date, despite the growing evidence, the heterogeneity of the psychological evidence associated with obesity has made it challenging to generate consensus on whether these psycho-behavioural phenotypes can be a complement to improve outcomes of existing interventions. For this reason, this narrative review is an overview focused on summarizing studies describing the psycho-behavioural phenotypes associated with obesity. Based on the literature, three psychological constructs have emerged: reward dependence, cognitive control, and mood and emotion. We discuss the clinical implications of stratifying and identifying these psycho-behavioural profiles as potential target for interventions which may ensure a better response to treatment in individuals with obesity. Our conclusions pointed out a considerable overlap between these psycho-behavioural phenotypes suggesting bidirectional interactions between them. These findings endorse the complexity of the psycho-behavioural features associated with obesity and reinforce the need to consider them in order to improve treatment outcomes.

The development of an immersive mixed-reality application to improve the ecological validity of eating and sensory behavior research

Introduction

The modern eating environment has been implicated as a driving force of the obesity epidemic. Mixed reality applications may improve traditional methodological assessments of eating behavior by improving the ecological validity of the laboratory setting.

Methods

Research experts evaluated the utility and ecological validity of a mixed reality application that allowed immersion within virtual environments through utilizing the passthrough cameras of the head mounted display to view and interact with real foods. An initial evaluation was conducted that involved three virtual environments: a traditional laboratory booth, a non-textured restaurant, and a full-textured restaurant. The feedback from the initial evaluation was used to create a new virtual restaurant environment and a subsequent evaluation was conducted.

Results

Nearly all research experts suggested adding social cues such as people and background noise to create a more authentic and ecologically valid experience. The experts scored the new virtual restaurant environment to be more acceptable than eating or conducting research in a sensory booth but scored lower when compared to conducting research in a real-world restaurant setting.

Discussion

The results of this evaluation suggest that mixed reality applications may be a new methodology to assess environmental influences of eating behavior and may be a promising direction for eating behavior and sensory science research.

Differences in child and adolescent exposure to unhealthy food and beverage advertising on television in a self-regulatory environment

BACKGROUND

Food and beverage promotion is a contributor to children's dietary behaviours, and ultimately, downstream health consequences. Broadcast television remains an important source of such advertising. The objective of this study was to examine and compare children and adolescent's exposure to food advertising on television in Canada over an entire year in a self-regulatory environment.

METHODS

Television advertising data for 57 selected food and beverage categories were licensed from Numerator for 36 stations in Toronto, for 2019. The estimated average number of advertisements viewed by children aged 2-11 and adolescents aged 12-17 was determined overall, by food category, and by marketing technique. The healthfulness of advertisements was also assessed using Health Canada's Nutrient Profile Model.

RESULTS

Overall in 2019, children viewed 2234.4 food ads/person/yr while adolescents viewed 1631.7 ads, exposure for both groups stemmed primarily from stations with general appeal, and both age groups were exposed to a range of powerful marketing techniques. Exposure to advertising for restaurants, snacks, breakfast food and candy and chocolate was high among both age groups and the healthfulness of most advertised products was considered poor. Adolescents were exposed to 36.4% more food products classified as unhealthy, had higher exposure to all marketing techniques examined, and were exposed to substantially more child-related marketing techniques compared to children.

CONCLUSION

Children and adolescents were heavily exposed to food advertisements on television in 2019. Despite current self-regulatory policies, children's exposure to unhealthy food and beverages remains high. Differences in exposure to food advertisements by food category and healthfulness may suggest that adolescents are being disproportionately targeted by food companies as a result of self-regulatory marketing restrictions.

Brain functional and structural magnetic resonance imaging of obesity and weight loss interventions

Obesity has tripled over the past 40 years to become a major public health issue, as it is linked with increased mortality and elevated risk for various physical and neuropsychiatric illnesses. Accumulating evidence from neuroimaging studies suggests that obesity negatively affects brain function and structure, especially within fronto-mesolimbic circuitry. Obese individuals show abnormal neural responses to food cues, taste and smell, resting-state activity and functional connectivity, and cognitive tasks including decision-making, inhibitory-control, learning/memory, and attention. In addition, obesity is associated with altered cortical morphometry, a lowered gray/white matter volume, and impaired white matter integrity. Various interventions and treatments including bariatric surgery, the most effective treatment for obesity in clinical practice, as well as dietary, exercise, pharmacological, and neuromodulation interventions such as transcranial direct current stimulation, transcranial magnetic stimulation and neurofeedback have been employed and achieved promising outcomes. These interventions and treatments appear to normalize hyper- and hypoactivations of brain regions involved with reward processing, food-intake control, and cognitive function, and also promote recovery of brain structural abnormalities. This paper provides a comprehensive literature review of the recent neuroimaging advances on the underlying neural mechanisms of both obesity and interventions, in the hope of guiding development of novel and effective treatments.

The Effects of Food Advertisements on Food Intake and Neural Activity: A Systematic Review and Meta-Analysis of Recent Experimental Studies

Food advertisements are ubiquitous in our daily environment. However, the relationships between exposure to food advertising and outcomes related to ingestive behavior require further investigation. The objective was to conduct a systematic review and meta-analysis of behavioral and neural responses to food advertising in experimental studies. PubMed, Web of Science, and Scopus were searched for articles published from January 2014 to November 2021 using a search strategy following PRISMA guidelines. Experimental studies conducted with human participants were included. A random-effects inverse-variance meta-analysis was performed on standardized mean differences (SMD) of food intake (behavioral outcome) between the food advertisement and nonfood advertisement conditions of each study. Subgroup analyses were performed by age, BMI group, study design, and advertising media type. A seed-based d mapping meta-analysis of neuroimaging studies was performed to evaluate neural activity between experimental conditions. Nineteen articles were eligible for inclusion, 13 for food intake (n = 1303) and 6 for neural activity (n = 303). The pooled analysis of food intake revealed small, but statistically significant, effects of increased intake after viewing food advertising compared with the control condition among adults and children (adult SMD: 0.16; 95% CI: 0.03, 0.28; P = 0.01; I² = 0; 95% CI: 0, 95.0%; Children SMD: 0.25; 95% CI: 0.14, 0.37; P < 0.0001; I² = 60.4%; 95% CI: 25.6%, 79.0%). The neuroimaging studies involved children only, and the pooled analysis corrected for multiple comparisons identified one significant cluster, the middle occipital gyrus, with increased activity after food advertising exposure compared with the control condition (peak coordinates: 30, -86, 12; z-value: 6.301, size: 226 voxels; P < 0.001). These findings suggest that acute exposure to food advertising increases food intake among children and adults and that the middle occipital gyrus is an implicated brain region among children. (PROSPERO registration: CRD42022311357).

Food Advertisement and Dietary Choices in Adolescents: An Overview of Recent Studies

Adolescents are exposed to food marketing through many routes, including television, movies, videos, print media, online games, and social media. The interplay between exposure to unhealthy food advertisements and food choices by adolescents is a field of special interest given the ongoing evolution of social media trends and marketing strategies. The purpose of this review was to synthesize the scientific findings in the last five years (2017–2022) regarding the possible influence of nutrition-related advertisements through television, social media, or video games on the choice and consumption of unhealthy foods and drinks in adolescents. Nineteen studies were included in this review. Adolescents exposed to unhealthy food and beverage advertising showed high desire and intention to consume the advertised foods, as evidenced by the majority of included studies. The effects of advertisements are reinforced by peer pressure and influencers and interact with socioeconomic, biological, and environmental factors. Food marketing represents part of the obesogenic environment of the present time.

Differential neural reward reactivity in response to food advertising medium in children

Introduction

Food cues including food advertisements (ads) activate brain regions related to motivation and reward. These responses are known to correlate with eating behaviors and future weight gain. The objective of this study was to compare brain responses to food ads by different types of ad mediums, dynamic (video) and static (images), to better understand how medium type impacts food cue response.

Methods

Children aged 9-12 years old were recruited to complete a functional magnetic resonance imaging (fMRI) paradigm that included both food and non-food dynamic and static ads. Anatomical and functional images were preprocessed using the fMRIPrep pipeline. A whole-brain analysis and a targeted region-of-interest (ROI) analysis for reward regions (nucleus accumbens, orbitofrontal cortex, amygdala, insula, hypothalamus, ventral tegmental area, substantia nigra) were conducted. Individual neural responses to dynamic and static conditions were compared using a paired t-test. Linear mixed-effects models were then constructed to test the differential response by ad condition after controlling for age, sex, BMI-z, physical activity, and % of kcal consumed of a participant's estimated energy expenditure in the pre-load prior to the MRI scan.

Results

A total of 115 children (mean=10.9 years) completed the fMRI paradigm. From the ROI analyses, the right and left hemispheres of the amygdala and insula, and the right hemisphere of the ventral tegmental area and substantia nigra showed significantly higher responses for the dynamic food ad medium after controlling for covariates and a false discovery rate correction. From the whole-brain analysis, 21 clusters showed significant differential responses between food ad medium including the precuneus, middle temporal gyrus, superior temporal gyrus, and inferior frontal gyrus, and all regions remained significant after controlling for covariates.

Discussion

Advertising medium has unique effects on neural response to food cues. Further research is needed to understand how this differential activation by ad medium ultimately affects eating behaviors and weight outcomes.

The role of reinforcement learning and value-based decision-making frameworks in understanding food choice and eating behaviors

The obesogenic food environment includes easy access to highly-palatable, energy-dense, "ultra-processed" foods that are heavily marketed to consumers; therefore, it is critical to understand the neurocognitive processes the underlie overeating in response to environmental food-cues (e.g., food images, food branding/advertisements). Eating habits are learned through reinforcement, which is the process through which environmental food cues become valued and influence behavior. This process is supported by multiple behavioral control systems (e.g., Pavlovian, Habitual, Goal-Directed). Therefore, using neurocognitive frameworks for reinforcement learning and value-based decision-making can improve our understanding of food-choice and eating behaviors. Specifically, the role of reinforcement learning in eating behaviors was considered using the frameworks of (1) Sign-versus Goal-Tracking Phenotypes; (2) Model-Free versus Model-Based; and (3) the Utility or Value-Based Model. The sign-and goal-tracking phenotypes may contribute a mechanistic insight on the role of food-cue incentive salience in two prevailing models of overconsumption-the Extended Behavioral Susceptibility Theory and the Reactivity to Embedded Food Cues in Advertising Model. Similarly, the model-free versus model-based framework may contribute insight to the Extended Behavioral Susceptibility Theory and the Healthy Food Promotion Model. Finally, the value-based model provides a framework for understanding how all three learning systems are integrated to influence food choice. Together, these frameworks can provide mechanistic insight to existing models of food choice and overconsumption and may contribute to the development of future prevention and treatment efforts.

Who Likes Unhealthy Food with a Strong Flavour? Influence of Sex, Age, Body Mass Index, Smoking and Olfactory Efficiency on Junk Food Preferences

Background. Unhealthy food is an important element in the development of diseases of civilisation. The aim of this study was to determine how sex, age, body mass index, smoking and olfactory efficiency influence the consumption of such foods. Methods. A total of 283 people living in the Silesian Voivodeship in Poland took part in the study. They were aged 18−82. An interview and olfactory tests were conducted together with assessments of food preferences from 25 types of food products. The extent to which sex, age, body mass index, tobacco addiction and sense of smell influence unhealthy food consumption was assessed. Results. Using the VARIMAX factor analysis, a coherent group of ‘unhealthy food with a strong flavour’ products was selected: crisps, salty snacks, fast food, sugary carbonated drinks and sour products. Unhealthy food was liked more by people who were younger (B = −0.04; PU = −0.05, −0.03; t = −7.43, eta2 = 0.17; p < 0.001) and who had a higher BMI (B = 0.03; PU ≤ 0.01, 0.06; t = 1.92, eta2 = 0.01; p = 0.056). The efficiency of the sense of smell does not play a significant role in the preference for the ‘unhealthy food’ group as a whole. The analysis of each type of unhealthy food separately showed that young people liked crisps, salty snacks, fast food and sugary carbonated drinks more, men liked fast food and sugary carbonated drinks more than women, and people with a good sense of smell liked sour products. Conclusion. According to the food preferences stated, dietary education should be targeted at young people, especially young men, to prevent the development of overweight and obesity.

Dissecting ultra-processed foods and drinks: Do they have a potential to impact the brain?

Ultra-processed foods and drinks (UPF) are formulation of ingredients, mostly of exclusive industrial use, that result from a series of industrial processes. They usually have a low nutrient but high energy density, with a high content of saturated and trans fats, and added sugars. In addition, they have characteristic organoleptic properties, and usually contain sophisticated additives, including artificial sweeteners, to intensify their sensory qualities and imitate the appearance of minimally processed foods. In addition, recent research has warned about the presence of chemicals (e.g., bisphenol) and neo-formed contaminants in these products. UPF production and consumption growth have been spectacular in the last decades, being specially consumed in children and adolescents. UPF features have been associated with a range of adverse health effects such as overeating, the promotion of inflammatory and oxidative stress processes, gut dysbiosis, and metabolic dysfunction including problems in glucose regulation. The evidence that these UPF-related adverse health effects may have on the neural network implicated in eating behavior are discussed, including the potential impact on serotonergic and dopaminergic neurotransmission, brain integrity and function. We end this review by placing UPF in the context of current food environments, by suggesting that an increased exposure to these products through different channels, such as marketing, may contribute to the automatic recruitment of the brain regions associated with food consumption and choice, with a detrimental effect on inhibitory-related prefrontal cortices. While further research is essential, preliminary evidence point to UPF consumption as a potential detrimental factor for brain health and eating behavior.

Efficacy of a combined food-response inhibition and attention training for weight loss

This Current Opinion in Behavioral Sciences article reviews trials that evaluated an obesity treatment that combines response-inhibition training with high-calorie foods and training designed to reduce attention for high-calorie foods. Two randomized controlled trials suggest that food-response inhibition and attention training produced significant body-fat loss, along with a reduction in valuation of, and reward-region response to, high-calorie foods. However, these effects did not emerge in a third trial, potentially because this trial used more heterogeneous food images, which reduced inhibition learning and attentional learning. Collectively, results suggest that food-response inhibition and attention training can devalue high-calorie foods and result in weight loss, but only if a homogeneous set of high-calorie and low-calorie food images is used.

Longitudinal Evidence of a Vicious Cycle Between Nucleus Accumbens Microstructure and Childhood Weight Gain

PURPOSE

Pediatric obesity is a growing public health concern. Previous work has observed diet to impact nucleus accumbens (NAcc) inflammation in rodents, measured by the reactive proliferation of glial cells. Recent work in humans has demonstrated a relationship between NAcc cell density-a proxy for neuroinflammation-and weight gain in youth; however, the directionality of this relationship in the developing brain and association with diet remains unknown.

METHODS

Waist circumference (WC) and NAcc cell density were collected in a large cohort of children (n > 2,000) participating in the Adolescent Brain Cognitive Development (ABCD) Study (release 3.0) at baseline (9-10 y) and at a Year 2 follow-up (11-12 y). Latent change score modeling (LCSM) was used to disentangle contributions of baseline measures to two-year changes in WC percentile and NAcc cellularity. In addition, the role of NAcc cellularity in mediating the relationship between diet and WC percentile was assessed using dietary intake data collected at Year 2.

RESULTS

LCSM indicates that baseline WC percentile influences change in NAcc cellularity and that baseline NAcc cell density influences change in WC percentile. NAcc cellularity was significantly associated with WC percentile at Year 2 and mediated the relationship between dietary fat consumption and WC percentile.

CONCLUSIONS

These results implicate a vicious cycle whereby NAcc cell density biases longitudinal changes in WC percentile and vice versa. Moreover, NAcc cell density may mediate the relationship between diet and weight gain in youth. These findings suggest that diet-induced inflammation of reward circuitry may lead to behavioral changes that further contribute to weight gain.

Playing with fruit: An experimental study to test the effectiveness of an online memory advergame to promote children's fruit consumption

OBJECTIVE

Literature on food marketing targeting young people reveals that in the last years, sophisticated marketing techniques have been developed to market predominantly unhealthy food products. Much research has been conducted to test the impact of these techniques on subsequent product selection and intake. Less is known about the effects of promoting healthier foods, although the health-related benefits of eating more fruit and vegetables for children are important. The main aim of the present experiment was to examine if an online advergame promoting a fruit brand with food products increased subsequent fruit intake by children.

METHODS

We used a randomized between-subject design with 123 children (age: 7-13 years) who played an advergame that promoted fruit (n = 43), non-food products (n = 40), or were in the control condition (n = 40). Subsequently, we measured the free intake of fruit as main outcome.

RESULTS

Playing the advergame promoting fruit did not stimulate the subsequent intake of fruit. Children in the advergame with fruit ate similar amounts of fruit than children in the control condition. No moderation effects of BMI, hunger, sex and game attitude were found. In addition, Bayesian analyses have been conducted that support the null hypothesis.

DISCUSSION

Previous research has shown that marketing of unhealthy products via advergames affects subsequent intake of the promoted product, but the same effect is not found for healthier foods. We suggest that future research should examine if longer exposure or different forms of novel food marketing are effective in increasing the intake of healthier foods. Until now, it is unclear if advergames as a marketing technique for healthy foods have the same effectiveness on the intake of healthier food products.

Conceptualizing and Measuring Appetite Self-Regulation Phenotypes and Trajectories in Childhood: A Review of Person-Centered Strategies

This review uses person-centered research and data analysis strategies to discuss the conceptualization and measurement of appetite self-regulation (ASR) phenotypes and trajectories in childhood (from infancy to about ages 6 or 7 years). Research that is person-centered provides strategies that increase the possibilities for investigating ASR phenotypes. We first examine the utility of examining underlying phenotypes using latent profile/class analysis drawing on cross-sectional data. The use of trajectory analysis to investigate developmental change is then discussed, with attention to phenotypes using trajectories of individual behaviors as well as phenotypes based on multi-trajectory modeling. Data analysis strategies and measurement approaches from recent examples of these person-centered approaches to the conceptualization and investigation of appetite self-regulation and its development in childhood are examined. Where relevant, examples from older children as well as developmental, clinical and educational psychology are drawn on to discuss when and how person-centered approaches can be used. We argue that there is scope to incorporate recent advances in biological and psychoneurological knowledge about appetite self-regulation as well as fundamental processes in the development of general self-regulation to enhance the examination of phenotypes and their trajectories across childhood (and beyond). The discussion and conclusion suggest directions for future research and highlight the potential of person-centered approaches to progress knowledge about the development of appetite self-regulation in childhood.

Neural Vulnerability Factors That Predict Future Weight Gain

PURPOSE OF REVIEW

The current article discusses five neural vulnerability theories for weight gain and reviews evidence from prospective studies using imaging and behavioral measures reflecting neural function, as well as randomized experiments with humans and animals that are consistent or inconsistent with these theories.

RECENT FINDINGS

Recent prospective imaging studies examining predictors of weight gain and response to obesity treatment, and repeated-measures imaging studies before and after weight gain and loss have advanced knowledge of etiologic processes and neural plasticity resulting from weight change. Overall, data provide strong support for the incentive sensitization theory of obesity and moderate support for the reward surfeit theory, inhibitory control deficit theory, and dynamic vulnerability model of obesity, which attempted to synthesize the former theories into a single etiologic model. Data provide little support for the reward deficit theory. Important directions for future studies are delineated.

Brain Responses to High-Calorie Visual Food Cues in Individuals with Normal-Weight or Obesity: An Activation Likelihood Estimation Meta-Analysis

Overconsumption of high-calorie or unhealthy foods commonly leads to weight gain. Understanding people’s neural responses to high-calorie food cues might help to develop better interventions for preventing or reducing overeating and weight gain. In this review, we conducted a coordinate-based meta-analysis of functional magnetic resonance imaging studies of viewing high-calorie food cues in both normal-weight people and people with obesity. Electronic databases were searched for relevant articles, retrieving 59 eligible studies containing 2410 unique participants. The results of an activation likelihood estimation indicate large clusters in a range of structures, including the orbitofrontal cortex (OFC), amygdala, insula/frontal operculum, culmen, as well as the middle occipital gyrus, lingual gyrus, and fusiform gyrus. Conjunction analysis suggested that both normal-weight people and people with obesity activated OFC, supporting that the two groups share common neural substrates of reward processing when viewing high-calorie food cues. The contrast analyses did not show significant activations when comparing obesity with normal-weight. Together, these results provide new important evidence for the neural mechanism underlying high-calorie food cues processing, and new insights into common and distinct brain activations of viewing high-calorie food cues between people with obesity and normal-weight people.

A narrative review of reward sensitivity, rash impulsivity, and food addiction in adolescents

Adolescence represents a neurodevelopmental period characterised by heightened reward drive and weaker inhibitory control that may increase vulnerability to compulsive overconsumption of highly-palatable foods and food addiction. This narrative review aimed to summarise research investigating the presence of food addiction in adolescents and establish the role that impulsivity traits (i.e., reward sensitivity and rash impulsivity), previously linked to substance and behavioural addictions, play in contributing to food addiction in this cohort. It was found that the prevalence of food addiction was typically higher in studies that recruited adolescents who were overweight/obese or from clinical populations. Overall, impulsivity was found to be more consistently associated with food addiction, while the relationships between measures of reward sensitivity and food addiction were mixed. Findings of this review suggest trait impulsivity may contribute to food addiction in adolescents, however, further longitudinal and prospective research is recommended to confirm these findings and to investigate the potential interactive effects of reward sensitivity and rash impulsivity.

The Impact of Social Crowding on Consumers' Online Mobile Shopping: Evidence from Behavior and ERPs

Purpose

Social crowding refers to the extent of social presence and proximity to others. A large number of studies have explored the effect of social crowding on consumers' feelings and behaviours in real shopping scenes, whereas few studies have examined the potential marketing effect of social crowding on online mobile consumption behaviour despite mobile commerce's increasing popularity in recent years. The current intends to explore the effect of social crowding on online mobile purchase and its underlying neural basis.

Methods

The current study employed a questionnaire survey and an implicit panic buying experiment, in which the participants were asked to press the button as soon as possible to buy the showed product. A 2-level social crowding (low vs high) × 2-level feedback of panic buying (success vs fail) design was employed to test the negative impact of social crowding on consumers' online mobile purchase intention by using electroencephalogram (EEG) recordings.

Results

Behaviorally, participants showed higher purchase intention in low social crowding environment compared with the high crowding condition. The event-related potentials (ERPs) results indicated that consumers had a higher affective/motivational evaluation (reflected in a smaller feedback-related negativity (FRN) amplitude) regarding the successful rather than the failing feedback in the low social crowding condition. However, this difference was not detected in the high social crowding condition. Meanwhile, more attentional resources (reflected in a greater P300 amplitude) were directed toward processing the feedback outcomes in the low rather than the high social crowding condition.

Conclusion

The current study provided neurophysiological response that social crowding negatively influences consumers' online purchase intention. Some implications for theory and practice were also discussed.

Reward-related neural correlates in adolescents with excess body weight

The functional and connectivity reward processing in adults with excessive body weight is well documented, though is relatively less researched during adolescence. Given that reward and inhibition may be highly malleable during adolescence, it is unknown how impulsive behaviors, potentially stemming from impaired inhibitory control and heightened sensitivity to rewarding cues, relate to increases in body weight in adolescents. Adolescents (N = 76; mean age = 14.10 years, SD = 1.92) with varied body mass index (BMI) performed a child-friendly monetary incentive delay task during functional magnetic resonance imaging, to study reward processing during the anticipation of rewards (cue) and reactions to feedback about rewards (feedback). Our results show that adolescents with greater BMI z-score show neural activation and ventral striatum connectivity alterations in networks implicated in reward, salience detection, and inhibitory control. These bottom-up reward and top-down inhibitory control networks, as well as interactions between these networks were prevalent during the anticipation period (when the cue is presented) as well as when receiving feedback about whether one has received a reward. Specifically, our results were mainly driven by failure to receive a reward in the feedback period, and the anticipation of a potential reward in the anticipation period. Overall, we provide evidence for heightened reward salience as well as inhibitory control deficits that, in combination, may contribute to the impulsive behaviors that lead to higher BMI in adolescents.

The association of adolescents' television viewing with Body Mass Index percentile, food addiction, and addictive phone use

Television (TV) viewing remain a popular forms of screen time for adolescents. Greater TV viewing is associated with a number of negative consequences for adolescent health. In a changing media landscape, it is important to understand adolescents' overall and commercial TV exposure, and how TV viewing is linked to health risks (e.g., obesity, food addiction, and phone addiction). The purpose of this study was to: 1) examine differences by age, gender, race/ethnicity, and parental education in overall TV and commercial TV viewing and 2) investigate whether adolescents who watch more overall TV and commercial TV programming were more likely to have a higher BMI percentile, more addictive eating, and more addictive phone use. A sample of 190 adolescents (13-16 years of age) completed Time-Use Diaries (TUDs) in 2015-2017. We found that girls had more overall weekday TV time than males. No other gender differences were detected for weekend TV time or commercial TV time. Higher BMI percentile was not correlated with greater overall or commercial TV viewing. However, we did identify a positive association between overall TV viewing and commercial TV viewing with addictive-eating and addictive phone use. This effect was mainly driven by boys. To our knowledge, this is the first study to investigate patterns of television viewing and addictive-like eating and addictive phone use. We conclude that adolescents, particularly boys, with higher TV viewing may be more likely to present with problems with addictive eating behavior and phone use. Our findings add to the research on the behavioral health correlates of TV viewing among adolescents.

In Search of the Most Reproducible Neural Vulnerability Factors that Predict Future Weight Gain: Analyses of Data from Six Prospective Studies

We tested if we could replicate the main effect relations of elevated striatum and lateral orbitofrontal cortex (OFC) response to high-calorie food stimuli to weight gain reported in past papers in six prospective datasets that used similar fMRI paradigms. Participants in Study 1 (N = 37; M age = 15.5), Study 2 (N = 160; M age = 15.3), Study 3 (N = 130; M age = 15.0), Study 4 (N = 175; M age = 14.3), Study 5 (N = 45; M age = 20.8), and Study 6 (N = 49; M age = 31.1) completed fMRI scans at baseline and had their BMI and body fat (Studies 4 and 6 only) measured at baseline and over follow-ups. Elevated striatal response to palatable food images predicted BMI gain in Studies 1 and 6 and body fat gain in Study 6. Lateral OFC activation did not predict weight gain in any of the six studies. Results provide limited support for the hypothesis that elevated reward region responsivity to palatable food images predicts weight gain. Factors that make replication difficult are discussed and potential solutions considered.

Neural Mechanisms of Food Decision-Making in Children

PURPOSE OF REVIEW

The goal of the current paper is to review the literature on the neural and behavioral factors involved in food decision-making in youth.

RECENT FINDINGS

Recent neuroimaging studies that employ passive viewing paradigms have found that exposure to food-related cues activate reward, motor planning, and attentional salience signals in children. Greater activations of reward signals and/or lower activations of control signals are associated with overeating and weight gain. Neuroimaging studies with decision-making paradigms have found the reward network in the brain activates during food choices, while control network activates less strongly. Findings suggest that exposure to food cues activates reward/valuation network, but activation of control network tends to be relatively weaker in children. Hedonic aspects of foods are predominantly considered in children's food choices, and their dietary self-control is not matured yet. The increased activation in reward network and the decreased activation in control network are associated with risk of developing obesity.

Episodic memory for food and non-food cues in females with obesity

Episodic memory is typically thought of as the memory system that makes possible mental time travel through subjective time. This may serve an important function in allowing us to use recent dietary information to predict future food needs and integrate this information with current food availability to adapt motivation accordingly. Growing evidence has suggested that episodic memory influences and is influenced by obesity. However, there is limited available evidence on the characteristics of episodic memory for food and non-food cues in people with obesity. The present study attempts to address this association and apply an episodic memory task to evaluate item memory and source memory for food and non-food cues in females with obesity. Participants were 26 females with obesity and 30 females with healthy weight, who were undergraduate students aged 17-24 years. They completed the Dutch Eating Behavior Questionnaire, hunger visual analog scale, fullness visual analog scale, desire-to-eat visual analog scale, and an episodic memory task including item memory and source memory. Results showed that the episodic memory patterns of females with and without obesity changed according to the type of stimuli. Specifically, females with obesity outperformed females with healthy weight in item memory for food cues, but showed deficits in item memory for non-food cues and source memory for both food and non-food cues. Taken together, based on the obesity and suboptimal food-related decision theoretical model, these findings are of great theoretical and clinical significance to explore episodic memory pattern differences between people with and without obesity.

Promoting Resilience to Food Commercials Decreases Susceptibility to Unhealthy Food Decision-Making

Children are vulnerable to adverse effects of food advertising. Food commercials are known to increase hedonic, taste-oriented, and unhealthy food decisions. The current study examined how promoting resilience to food commercials impacted susceptibility to unhealthy food decision-making in children. To promote resilience to food commercials, we utilized the food advertising literacy intervention intended to enhance cognitive skepticism and critical thinking, and decrease positive attitudes toward commercials. Thirty-six children aged 8–12 years were randomly assigned to the food advertising literacy intervention or the control condition. Eighteen children received four brief intervention sessions via video over 1 week period. In each session, children watched six food commercials with interspersed embedded intervention narratives. While watching food commercials and narratives, children were encouraged to speak their thoughts out loud spontaneously (“think-aloud”), which provided children's attitudes toward commercials. Eighteen children in the control condition had four control sessions over 1 week, and watched the same food commercials without intervention narratives while thinking aloud. The first and last sessions were held in the laboratory, and the second and third sessions were held at the children's homes. Susceptibility to unhealthy food decision-making was indicated by the decision weights of taste attributes, taste perception, food choices, ad libitum snacking, and cognitive and affective attitudes toward food commercials. As hypothesized, the intervention successfully decreased susceptibility to unhealthy food decision-making evidenced by reduced decision weights of the taste in food decisions, decreased tasty perception of unhealthy foods, and increased cognitive skepticism and critical thinking toward food commercials. In addition, as children's opinions assimilated to intervention narratives, their cognitive skepticism and critical thinking toward commercials increased. The aforementioned results were not shown in the control condition. However, this brief intervention was not enough to change actual food choices or food consumption. Results of this study suggest that promoting resilience to food commercials by enhancing cognitive skepticism and critical thinking effectively reduced children's susceptibility to unhealthy food-decision making.

Food Addiction and Psychosocial Adversity: Biological Embedding, Contextual Factors, and Public Health Implications

The role of stress, trauma, and adversity particularly early in life has been identified as a contributing factor in both drug and food addictions. While links between traumatic stress and substance use disorders are well documented, the pathways to food addiction and obesity are less established. This review focuses on psychosocial and neurobiological factors that may increase risk for addiction-like behaviors and ultimately increase BMI over the lifespan. Early childhood and adolescent adversity can induce long-lasting alterations in the glucocorticoid and dopamine systems that lead to increased addiction vulnerability later in life. Allostatic load, the hypothalamic-pituitary-adrenal axis, and emerging data on epigenetics in the context of biological embedding are highlighted. A conceptual model for food addiction is proposed, which integrates data on the biological embedding of adversity as well as upstream psychological, social, and environmental factors. Dietary restraint as a feature of disordered eating is discussed as an important contextual factor related to food addiction. Discussion of various public health and policy considerations are based on the concept that improved knowledge of biopsychosocial mechanisms contributing to food addiction may decrease stigma associated with obesity and disordered eating behavior.

Brain Responses to Food Odors Associated With BMI Change at 2-Year Follow-Up

The understanding of food cue associated neural activations that predict future weight variability may guide the design of effective prevention programs and treatments for overeating and obesity. The current study investigated the association between brain response to different food odors with varied energy density and individual changes of body mass index (BMI) over 2 years. Twenty-five participants received high-fat (chocolate and peanut), low-fat (bread and peach) food odors, and a nonfood odor (rose) while the brain activation was measured using functional magnetic resonance imaging (fMRI). BMIs were calculated with participant’s self-reported body weight and height collected at the time of the fMRI scan and again at 2 years later. Regression analyses revealed significant negative correlations between BMI increase over 2 years and brain activation of the bilateral precuneus and the right posterior cingulate cortex (PCC) in response to high-fat vs. low-fat food odors. Also, brain activation of the right supplementary motor area (SMA) in response to food vs. non-food odor was negatively correlated to subsequent BMI increase over 2 years. Taken together, the current findings suggest that individual differences in neural responsivity to (high calorie) food odors in brain regions of the default mode and motor control network serve as a neural marker for future BMI change.

Brain responses to watching food commercials compared with nonfood commercials: a meta-analysis on neuroimaging studies

OBJECTIVE

This study aimed to identify and meta-analyse the neuroimaging data and hence synthesise a brain map showing the neural correlates of watching food commercials.

DESIGN

Published studies were retrieved and included into the analysis if they evaluated brain responses to food commercials with functional MRI and reported results based on whole-brain analysis in standard brain coordinates.

SETTING

No additional restriction was placed on the search, such as the publication year and age of participants.

PARTICIPANTS

Seven papers that composed of a total of 442 participants fulfilled the inclusion criteria. All of them recruited children or adolescents.

RESULTS

Food commercials caused larger brain responses than nonfood counterparts in the cuneus on both hemispheres, which played a role in dietary self-control and modulation of food craving. Other brain regions involved in food commercials processing included the left culmen, left middle occipital gyrus and the right superior parietal lobule, which could be related to reward, emotional responses and habit formation.

CONCLUSION

These neural correlates may help explain the food choice and eating behaviours of children and adolescents that might be relevant to the development of obesity.

Weight-Related Differences in Salience, Default Mode, and Executive Function Network Connectivity in Adolescents

OBJECTIVE

The current study examined whether adolescents with weight status ranging from lean to obesity showed weight-related differences in the default mode network (DMN), the executive function network (EFN), and the salience network (SN).

METHODS

One hundred sixty-four adolescents participated in a resting-state functional connectivity scan. A general linear model was used to examine differences in scan patterns among adolescents with lean weight, overweight, and obesity.

RESULTS

Adolescents with obesity compared with those with lean weight showed stronger within-SN connectivity among the medial orbitofrontal cortex, olfactory tubercle, and pallidum; however, they showed lower connectivity between the amygdala and SN regions (nucleus accumbens, thalamus, putamen). Those with obesity also showed lower connectivity between SN (amygdala, caudate) and DMN (parahippocampus, hippocampus, precuneus) regions. Adolescents with obesity compared with those with lean weight showed lower connectivity between SN (medial orbitofrontal cortex) and EFN (ventrolateral prefrontal cortex) regions.

CONCLUSIONS

Obesity appears to be related to stronger connectivity within and between regions implicated in determining the salience of stimuli, which may have implications for reward processing. Lower connectivity between SN and EFN regions may suggest that executive-control efforts are going "off-line" when salience and reward-processing regions are engaged in adolescents who have obesity.

Adolescents' Addictive Phone Use: Associations with Eating Behaviors and Adiposity

Concerns have been raised about excessive or "addictive" phone use among adolescents, and the impact that addictive phone use (APU) can have on adolescent development and health. Most research on the physical health correlates of smartphone use has been limited to sleep health, whereas other outcomes, such as eating behaviors and obesity risk have not received as much attention. To address this gap in the literature, we examined the association between APU and emotion regulation difficulties, impulsivity, maladaptive eating behaviors, and adiposity in a sample of 111 adolescents. We found that APU is associated with greater emotion regulation difficulties, dysregulated eating, restrained eating, food addiction, and higher percent body fat. Further, we found that emotion regulation difficulties mediated the association between APU and dysregulated eating, restrained eating, and food addiction. Findings suggest that addictive phone use may confer increased risk for obesogenic eating behaviors and food addiction via challenges in regulating emotions.

See, Like, Share, Remember: Adolescents' Responses to Unhealthy-, Healthy- and Non-Food Advertising in Social Media

Media-saturated digital environments seek to influence social media users’ behaviour, including through marketing. The World Health Organization has identified food marketing, including advertising for unhealthy items, as detrimental to health, and in many countries, regulation restricts such marketing and advertising to younger children. Yet regulation rarely addresses adolescents and few studies have examined their responses to social media advertising. In two studies, we examined adolescents’ attention, memory and social responses to advertising posts, including interactions between product types and source of posts. We hypothesized adolescents would respond more positively to unhealthy food advertising compared to healthy food or non-food advertising, and more positively to ads shared by peers or celebrities than to ads shared by a brand. Outcomes measured were (1a) social responses (likelihood to ‘share’, attitude to peer); (1b) brand memory (recall, recognition) and (2) attention (eye-tracking fixation duration and count). Participants were 151 adolescent social media users (Study 1: n = 72; 13–14 years; M = 13.56 years, SD = 0.5; Study 2: n = 79, 13–17 years, M = 15.37 years, SD = 1.351). They viewed 36 fictitious Facebook profile feeds created to show age-typical content. In a 3 × 3 factorial design, each contained an advertising post that varied by content (healthy/unhealthy/non-food) and source (peer/celebrity/company). Generalised linear mixed models showed that advertisements for unhealthy food evoked significantly more positive responses, compared to non-food and healthy food, on 5 of 6 measures: adolescents were more likely to wish to ‘share’ unhealthy posts; rated peers more positively when they had unhealthy posts in their feeds; recalled and recognised a greater number of unhealthy food brands; and viewed unhealthy advertising posts for longer. Interactions with sources (peers, celebrities and companies) were more complex but also favoured unhealthy food advertising. Implications are that regulation of unhealthy food advertising should address adolescents and digital media.