Midbrain response to milkshake correlates with ad libitum milkshake intake in the absence of hunger

Caloric labels do not influence taste pleasantness and neural responses to erythritol and sucrose

INTRODUCTION

The beneficial effects of substituting sugar with non-caloric sweeteners (NCSs) remain uncertain due to the mismatch between their rewarding sweet taste and lack of energy content. Functional magnetic resonance imaging (fMRI) studies indicate an influence of cognitive processes (e.g., beliefs, expectations) on reward system responses to NCSs, thereby changing their rewarding properties. We measured the impact of cognitive influences about the caloric content on brain responses and liking ratings to erythritol, a natural NCS with satiating properties, versus sugar (i.e., sucrose).

METHODS

We performed a within-subject, single-blind, counterbalanced fMRI study in 30 healthy males (mean ± SD: age 23 ± 0.6 years, BMI 22.5 ± 0.3 kg/m²). Concentrations of erythritol were individually titrated to match the perceived sweetness intensity of a 16 % sucrose solution. During the scan, sucrose and equisweet erythritol solutions were delivered as 1 mL sips with either correct or purposefully incorrect "low-calorie" or "high-calorie" labels. After each sip, participants rated sweetness liking. Water with a "water" label was used as the control condition.

RESULTS

A 2 × 2 ANOVA revealed lower liking ratings for erythritol than sucrose (p < 0.0001), but no main effect of the label, nor label-by-sweetener interaction. General Linear Model (GLM) analysis of brain responses at FDR q < 0.05 showed no main effect of sweetener nor label, nor a label-by-sweetener interaction. However, several patterns of brain activity mediated the differences in subjective liking ratings between the sweeteners. Moreover, different neural responses were found for sucrose vs. water in parcel-wise, SVM, and ROI-based analyses, whereas for erythritol vs. water, only the latter two showed differences. Lastly, sucrose induced a stronger craving signature response compared to erythritol, driven by the pattern specific to drug craving.

CONCLUSION

Liking ratings were lower for erythritol than sucrose, and they were unaffected by the caloric label. There were no differences in neural responses between the sweeteners and labels, except in comparisons with water.

Neural responses to oral administration of erythritol vs. sucrose and sucralose explain differences in subjective liking ratings

INTRODUCTION

High sugar intake is associated with many chronic diseases. However, non-caloric sweeteners (NCSs) might fail to successfully replace sucrose due to the mismatch between their rewarding sweet taste and lack of caloric content. The natural NCS erythritol has been proposed as a sugar substitute due to its satiating properties despite being non-caloric. We aimed to compare brain responses to erythritol vs. sucrose and the artificial NCS sucralose in a priori taste, homeostatic, and reward brain regions of interest (ROIs).

METHODS

We performed a within-subject, single-blind, counterbalanced fMRI study in 30 healthy men (mean ± SEM age:24.3 ± 0.8 years, BMI:22.3 ± 0.3 kg/m2). Before scanning, we individually matched the concentrations of both NCSs to the perceived sweetness intensity of a 10% sucrose solution. During scanning, participants received 1 mL sips of the individually titrated equisweet solutions of sucrose, erythritol, and sucralose, as well as water. After each sip, they rated subjective sweetness liking.

RESULTS

Liking ratings were significantly higher for sucrose and sucralose vs. erythritol (both pHolm = 0.0037); water ratings were neutral. General Linear Model (GLM) analyses of brain blood oxygen level-depended (BOLD) responses at qFDR<0.05 showed no differences between any of the sweeteners in a priori ROIs, but distinct differences were found between the individual sweeteners and water. These results were confirmed by Bayesian GLM and machine learning-based models. However, several brain response patterns mediating the differences in liking ratings between the sweeteners were found in whole-brain multivariate mediation analyses. Both subjective and neural responses showed large inter-subject variability.

CONCLUSION

We found lower liking ratings in response to oral administration of erythritol vs. sucrose and sucralose, but no differences in neural responses between any of the sweeteners in a priori ROIs. However, differences in liking ratings between erythritol vs. sucrose or sucralose are mediated by multiple whole-brain response patterns.

Hedonic hunger, ultra-processed food consumption, and the moderating effects of impulsivity in pregnant individuals with body mass index ≥ 25

Evidence suggests higher hedonic hunger (preoccupation with/desire to consume food for pleasure) is associated with greater ultra-processed food (UPF) consumption in non-pregnant individuals with higher, but not lower, self-report impulsivity or delay discounting. The current study tested the association between hedonic hunger and UPF consumption, and the moderating effects of self-report impulsivity and delay discounting, during pregnancy. Individuals (N = 220) with body mass index (BMI)≥25 completed the Power of Food Scale, 24-h dietary recalls, and Barratt Impulsiveness Scale-Version 11 in early-mid pregnancy. A subset enrolled in an ancillary study (n = 143) completed a Delay Discounting Task. Linear regression and moderation models covaried for age, gestational age, pre-pregnancy BMI, and socioeconomic status. The association between hedonic hunger and UPF consumption was nonsignificant (p = 0.47). Self-report impulsivity was not a significant moderator (p = 0.11), but delay discounting was (p = 0.01). Simple slopes analysis revealed a one-unit increase in hedonic hunger was associated with 7% lower UPF intake among participants with lower (M+1SD) delay discounting (p = 0.01) and 1% higher UPF intake among those with higher (M-1SD) delay discounting (p = 0.57). Findings contrast those from research with non-pregnant samples and indicate lower delay discounting may serve as a protective factor, associated with reduced UPF consumption at higher levels of hedonic hunger, during pregnancy.

Structural Connectivity between Olfactory Tubercle and Ventrolateral Periaqueductal Gray Implicated in Human Feeding Behavior

The olfactory tubercle (TUB), also called the tubular striatum, receives direct input from the olfactory bulb and, along with the nucleus accumbens, is one of the two principal components of the ventral striatum. As a key component of the reward system, the ventral striatum is involved in feeding behavior, but the vast majority of research on this structure has focused on the nucleus accumbens, leaving the TUB's role in feeding behavior understudied. Given the importance of olfaction in food seeking and consumption, olfactory input to the striatum should be an important contributor to motivated feeding behavior. Yet the TUB is vastly understudied in humans, with very little understanding of its structural organization and connectivity. In this study, we analyzed macrostructural variations between the TUB and the whole brain and explored the relationship between TUB structural pathways and feeding behavior, using body mass index (BMI) as a proxy in females and males. We identified a unique structural covariance between the TUB and the periaqueductal gray (PAG), which has recently been implicated in the suppression of feeding. We further show that the integrity of the white matter tract between the two regions is negatively correlated with BMI. Our findings highlight a potential role for the TUB-PAG pathway in the regulation of feeding behavior in humans.

Prebiotic diet changes neural correlates of food decision-making in overweight adults: a randomised controlled within-subject cross-over trial

OBJECTIVE

Animal studies suggest that prebiotic, plant-derived nutrients could improve homoeostatic and hedonic brain functions through improvements in microbiome-gut-brain communication. However, little is known if these results are applicable to humans. Therefore, we tested the effects of high-dosed prebiotic fibre on reward-related food decision-making in a randomised controlled within-subject cross-over study and assayed potential microbial and metabolic markers.

DESIGN

59 overweight young adults (19 females, 18-42 years, body mass index 25-30 kg/m2) underwent functional task MRI before and after 14 days of supplementary intake of 30 g/day of inulin (prebiotics) and equicaloric placebo, respectively. Short chain fatty acids (SCFA), gastrointestinal hormones, glucose/lipid and inflammatory markers were assayed in fasting blood. Gut microbiota and SCFA were measured in stool.

RESULTS

Compared with placebo, participants showed decreased brain activation towards high-caloric wanted food stimuli in the ventral tegmental area and right orbitofrontal cortex after prebiotics (preregistered, family wise error-corrected p <0.05). While fasting blood levels remained largely unchanged, 16S-rRNA sequencing showed significant shifts in the microbiome towards increased occurrence of, among others, SCFA-producing Bifidobacteriaceae, and changes in >60 predicted functional signalling pathways after prebiotic intake. Changes in brain activation correlated with changes in Actinobacteria microbial abundance and associated activity previously linked with SCFA production, such as ABC transporter metabolism.

CONCLUSIONS

In this proof-of-concept study, a prebiotic intervention attenuated reward-related brain activation during food decision-making, paralleled by shifts in gut microbiota.

TRIAL REGISTRATION NUMBER

NCT03829189.

The effects of an 8-week mindful eating intervention on anticipatory reward responses in striatum and midbrain

Introduction

Accumulating evidence suggests that increased neural responses during the anticipation of high-calorie food play an important role in the tendency to overeat. A promising method for counteracting enhanced food anticipation in overeating might be mindfulness-based interventions (MBIs). However, the neural mechanisms by which MBIs can affect food reward anticipation are unclear. In this randomized, actively controlled study, the primary objective was to investigate the effect of an 8-week mindful eating intervention on reward anticipation. We hypothesized that mindful eating would decrease striatal reward anticipation responses. Additionally, responses in the midbrain-from which the reward pathways originate-were explored.

Methods

Using functional magnetic resonance imaging (fMRI), we tested 58 healthy participants with a wide body mass index range (BMI: 19-35 kg/m2), motivated to change their eating behavior. During scanning they performed an incentive delay task, measuring neural reward anticipation responses to caloric and monetary cues before and after 8 weeks of mindful eating or educational cooking (active control).

Results

Compared with the educational cooking intervention, mindful eating affected neural reward anticipation responses, with reduced caloric relative to monetary reward responses. This effect was, however, not seen in the striatum, but only in the midbrain. The secondary objective was to assess temporary and long-lasting (1 year follow-up) intervention effects on self-reported eating behavior and anthropometric measures [BMI, waist circumference, waist-to-hip-ratio (WHR)]. We did not observe effects of the mindful eating intervention on eating behavior. Instead, the control intervention showed temporary beneficial effects on BMI, waist circumference, and diet quality, but not on WHR or self-reported eating behavior, as well as long-lasting increases in knowledge about healthy eating.

Discussion

These results suggest that an 8-week mindful eating intervention may have decreased the relative salience of food cues by affecting midbrain but not striatal reward responses, without necessarily affecting regular eating behavior. However, these exploratory results should be verified in confirmatory research.The primary and secondary objectives of the study were registered in the Dutch Trial Register (NTR): NL4923 (NTR5025).

Do eating behavior traits predict energy intake and body mass index? A systematic review and meta-analysis

At present, it is unclear whether eating behavior traits (EBT) predict objectively measured short-term energy intake (EI) and longer-term energy balance as estimated by body mass index (BMI). This systematic review examined the impact of EBT on BMI and laboratory-based measures of EI in adults ( ≥ 18 years) in any BMI category, excluding self-report measures of EI. Articles were searched up until 28th October 2021 using MEDLINE, PsycINFO, EMBASE and Web of Science. Sixteen EBT were identified and the association between 10 EBT, EI and BMI were assessed using a random-effects meta-analysis. Other EBT outcomes were synthesized qualitatively. Risk of bias was assessed with the mixed methods appraisal tool. A total of 83 studies were included (mean BMI = 25.20 kg/m² , mean age = 27 years and mean sample size = 70). Study quality was rated moderately high overall, with some concerns in sampling strategy and statistical analyses. Susceptibility to hunger (n = 6) and binge eating (n = 7) were the strongest predictors of EI. Disinhibition (n = 8) was the strongest predictor of BMI. Overall, EBT may be useful as phenotypic markers of susceptibility to overconsume or develop obesity (PROSPERO: CRD42021288694).

Olfactory decoding is positively associated with ad libitum food intake in sated humans

The role of olfaction in eating behavior and body weight regulation is controversial. Here we reanalyzed data from a previous functional magnetic resonance imaging study to test whether central olfactory coding is associated with hunger/satiety state, food intake, and change in body weight over one year in healthy human adults. Since odor quality and category are coded across distributed neural patterns that are not discernible with traditional univariate analyses, we used multi-voxel pattern analyses to decode patterns of brain activation to food versus nonfood odors. We found that decoding accuracies in the piriform cortex and amygdala were greater in the sated compared to hungry state. Sated decoding accuracies in these and other regions were also associated with post-scan ad libitum food intake, but not with weight change. These findings demonstrate that the fidelity of olfactory decoding is influenced by meal consumption and is associated with immediate food intake, but not longer-term body weight regulation.

Food cue reactivity: Neurobiological and behavioral underpinnings

The modern obesogenic environment contains an abundance of food cues (e.g., sight, smell of food) as well cues that are associated with food through learning and memory processes. Food cue exposure can lead to food seeking and excessive consumption in otherwise food-sated individuals, and a high level of food cue responsivity is a risk factor for overweight and obesity. Similar food cue responses are observed in experimental rodent models, and these models are therefore useful for mechanistically identifying the neural circuits mediating food cue responsivity. This review draws from both experimental rodent models and human data to characterize the behavioral and biological processes through which food-associated stimuli contribute to overeating and weight gain. Two rodent models are emphasized - cue-potentiated feeding and Pavlovian-instrumental transfer - that provide insight in the neural circuits and peptide systems underlying food cue responsivity. Data from humans are highlighted that reveal physiological, psychological, and neural mechanisms that connect food cue responsivity with overeating and weight gain. The collective literature identifies connections between heightened food cue responsivity and obesity in both rodents and humans, and identifies underlying brain regions (nucleus accumbens, amygdala, orbitofrontal cortex, hippocampus) and endocrine systems (ghrelin) that regulate food cue responsivity in both species. These species similarities are encouraging for the possibility of mechanistic rodent model research and further human research leading to novel treatments for excessive food cue responsivity in humans.

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.

Sensory cue reactivity: Sensitization in alcohol use disorder and obesity

Neuroimaging techniques to measure the function of the human brain such as electroencephalography (EEG), positron emission tomography (PET), and functional magnetic resonance imaging (fMRI), are powerful tools for understanding the underlying neural circuitry associated with alcohol use disorder (AUD) and obesity. The sensory (visual, taste and smell) paradigms used in neuroimaging studies represent an ideal platform to investigate the connection between the different neural circuits subserving the reward/executive control systems in these disorders, which may offer a translational mechanism for novel intervention predictions. Thus, the current review provides an integrated summary of the recent neuroimaging studies that have applied cue-reactivity paradigms and neuromodulation strategies to explore underlying alterations in neural circuitry as well in treatment strategies in AUD and obesity. Finally, we discuss literature on mechanisms associated with increased alcohol sensitivity post-bariatric surgery (BS) which offers guidance for future research to use sensory percepts in elucidating the relation of reward signaling in AUD development post-BS.

Test-retest reliability of functional MRI food receipt, anticipated receipt, and picture tasks

BACKGROUND

Functional MRI (fMRI) tasks are increasingly being used to advance knowledge of the etiology and maintenance of obesity and eating disorders. Thus, understanding the test-retest reliability of BOLD signal contrasts from these tasks is important.

OBJECTIVES

To evaluate test-retest reliability of responses in reward-related brain regions to food receipt paradigms (palatable tastes, anticipated palatable tastes), food picture paradigms (high-calorie food pictures), a monetary reward paradigm (winning money and anticipating winning money), and a thin female model picture paradigm (thin female model pictures).

METHOD

We conducted secondary univariate contrast-based analyses in data drawn from 4 repeated-measures fMRI studies. Participants (Study 1: N = 60, mean [M] age = 15.2 ± 1.1 y; Study 2: N = 109, M age = 15.1 ± 0.9 y; Study 3: N = 39, M age = 21.2 ± 3.7 y; Study 4: N = 62, M age = 29.7 ± 6.2 y) completed the same tasks over 3-wk to 3-y test-retest intervals. Studies 3 and 4 included participants with eating disorders and obesity, respectively.

RESULTS

Test-retest reliability of the food receipt and food picture paradigms was poor, with average ICC values ranging from 0.07 to 0.20. The monetary reward paradigm and the thin female model picture paradigm also showed poor test-retest reliability: average ICC values 0.21 and 0.12, respectively. Although several regions demonstrated moderate to good test-retest reliability, these results did not replicate across studies using similar paradigms. In Studies 3 and 4, but not Study 1, test-retest reliability in visual processing regions was moderate to good when contrasting single conditions with a low-level baseline.

CONCLUSIONS

Results underscore the importance of examining the temporal reliability of fMRI tasks and call for the development and use of well-validated standardized fMRI tasks in eating- and obesity-related studies that can provide more reliable measures of neural activation. The trials were registered at clinicaltrials.gov as NCT02084836, NCT01949636, NCT03261050, and NCT03375853.

Basal ganglia lateralization in different types of reward

Reward processing is a fundamental human activity. The basal ganglia are recognized for their role in reward processes; however, specific roles of the different nuclei (e.g., nucleus accumbens, caudate, putamen and globus pallidus) remain unclear. Using quantitative meta-analyses we assessed whole-brain and basal ganglia specific contributions to money, erotic, and food reward processing. We analyzed data from 190 fMRI studies which reported stereotaxic coordinates of whole-brain, within-group results from healthy adult participants. Results showed concordance in overlapping and distinct cortical and sub-cortical brain regions as a function of reward type. Common to all reward types was concordance in basal ganglia nuclei, with distinct differences in hemispheric dominance and spatial extent in response to the different reward types. Food reward processing favored the right hemisphere; erotic rewards favored the right lateral globus pallidus and left caudate body. Money rewards engaged the basal ganglia bilaterally including its most anterior part, nucleus accumbens. We conclude by proposing a model of common reward processing in the basal ganglia and separate models for money, erotic, and food rewards.

Common and distinct neural correlates of music and food-induced pleasure: A coordinate-based meta-analysis of neuroimaging studies

Neuroimaging studies have shown that, despite the abstractness of music, it may mimic biologically rewarding stimuli (e.g., food) in its ability to engage the brain's reward circuitry. However, due to the lack of research comparing music and other types of reward, it is unclear to what extent the recruitment of reward-related structures overlaps among domains. To achieve this goal, we performed a coordinate-based meta-analysis of 38 neuroimaging studies (703 subjects) comparing the brain responses specifically to music and food-induced pleasure. Both engaged a common set of brain regions, including the ventromedial prefrontal cortex, ventral striatum, and insula. Yet, comparative analyses indicated a partial dissociation in the engagement of the reward circuitry as a function of the type of reward, as well as additional reward type-specific activations in brain regions related to perception, sensory processing, and learning. These results support the idea that hedonic reactions rely on the engagement of a common reward network, yet through specific routes of access depending on the modality and nature of the reward.

A Systematic Review and Activation Likelihood Estimation Meta-Analysis of fMRI Studies on Sweet Taste in Humans

BACKGROUND

The reward value of palatable foods is often cited as an important influence on eating behaviors, including intake of sugars. However, human neuroimaging studies have generated conflicting evidence on the basic neural representation of taste and reward responses to caloric sweeteners (sucrose and glucose), and most relevant studies have used small subject numbers.

OBJECTIVE

We conducted a systematic review and a coordinate-based meta-analysis of studies reporting brain responses to oral sugar solutions.

METHODS

A systematic search of MEDLINE, Scopus, and PsycINFO through October 2019 identified fMRI studies (in healthy human adults, including those with overweight or obesity) assessing differences in responses to purified sweet and nonsweet taste stimuli. Data were extracted with the primary objective of quantifying evidence for the activation of brain regions associated with caloric sweet taste sensation. We used activation likelihood estimation meta-analysis methods. We also performed multiple sensitivity analyses to assess the generality of effects.

RESULTS

Of 455 unique articles, 15 met the criteria for inclusion. These contributed to 2 primary meta-analyses: 1) sucrose (13 experiments, 179 coordinates, n = 241) and 2) sucrose + glucose (16 experiments, 209 coordinates, n = 262). Consistent activation was apparent in primary taste areas: insula (69.2% of studies) and opercular cortex (76.9% of studies), precentral gyri (53.9% of studies), and globus pallidus and postcentral gyrus (30.8% of studies for each). Evidence of reward activity (caudate) was seen in the primary analyses (30.8% of studies) but not in sensitivity analysis.

CONCLUSIONS

We confirm the importance of primary taste areas for gustatory processing in human adults. We also provide tentative evidence for reward-related caudate activity in relation to the sweet taste of caloric sugars. A number of factors affect the observation and interpretation of brain responses, including reward-related activity. Firm conclusions require confirmation with large data set studies.

INVESTIGATION OF INFLUENCE OF TECHNOLOGICAL FACTORS ON CONSUMPTION PROPERTIES FORMATION IN MILK-CHERRY SMOOTHIE

The aim of our work is to study the structure of the food system of milk-cherry smoothie with given high consumption indices (increased content of macronutrients and easily-assimilated protein); it allows to widen the assortment of healthy beverages at enterprises of restaurant economy. The effectiveness of functioning of restaurant economy enterprises is, in the first turn, determined by the extent, to which their strategic actions correspond to long-term market requirements. A market condition in the field of restaurant economy is a driver for developing innovative products and technologies for getting culinary products. At developing aerated products, the main factor of getting a high-quality one is technological regimes for getting an aerated structure. An influence of temperature and shaking time on the foam-forming ability of a food system and smoothie form stability, including milk whey, cherry juice, apple pectin and collagen hydrolysate, was studied. It has been established, that most foam-formation (62 %) is attained at shaking smoothie under the following conditions: temperature – 10 °С, shaking time – 90 seconds. The maximal number of air bubbles in smoothie has the diameter d=(0,32±0,01) mm. High multiplicity indices of the smoothie foam structure (250 %) characterize the high product stability index. The obtained data as to the development of the technological process of getting the aerated smoothie structure give a possibility to recommend the developed technology for producing smoothie at restaurant economy enterprises.

Food cue reactivity in food addiction: A functional magnetic resonance imaging study

BACKGROUND

While neuroimaging studies have revealed that reward dysfunction may similarly contribute to obesity and addiction, no prior studies have examined neural responses in individuals who meet the "clinical" food addiction phenotype.

METHODS

Women (n = 44) with overweight and obesity, nearly half of whom (n = 20) met criteria for moderate-to-severe Yale Food Addiction Scale 2.0 (YFAS 2.0) food addiction, participated in a functional magnetic resonance imaging cue reactivity task. Participants viewed images of highly processed foods, minimally processed foods, and household objects while thinking about how much they wanted each item. Differences in neural responses by YFAS 2.0 food addiction to highly processed and minimally processed food cues were investigated.

RESULTS

There was a significant interaction between participant group and neural response in the right superior frontal gyrus to highly versus minimally processed food cues (r = 0.57). Individuals with YFAS 2.0 food addiction exhibited modest, elevated responses in the superior frontal gyrus for highly processed food images and more robust, decreased activations for minimally processed food cues, whereas participants in the control group showed the opposite responses in this region. Across all participants, the household items elicited greater activation than the food cues in regions associated with interoceptive awareness and visuospatial attention (e.g., insula, inferior frontal gyrus, inferior parietal lobe).

CONCLUSIONS

Women with overweight or obesity and YFAS 2.0 food addiction, compared to those with only overweight or obesity, exhibited differential responses to highly and minimally processed food cues in a region previously associated with cue-induced craving in persons with a substance-use disorder. Overall, the present work provides further support for the utility of the food addiction phenotype within overweight and obesity.

Neural vulnerability factors for obesity

Multiple theories identify neural vulnerability factors that may increase risk for overeating and weight gain. Early cross-sectional neuroimaging studies were unable to determine whether aberrant neural responsivity was a risk factor for or a consequence of overeating. More recent obesity risk, prospective, repeated-measures, and experimental neuroimaging studies with humans have advanced knowledge of etiologic processes and neural plasticity resulting from overeating. Herein, we review evidence from these more rigorous human neuroimaging studies, in conjunction with behavioral measures reflecting neural function, as well as experiments with animals that investigated neural vulnerability theories for overeating. Findings provide support for the reward surfeit theory that posits that individuals at risk for obesity initially show hyper-responsivity of reward circuitry to high-calorie food tastes, which theoretically drives elevated intake of such foods. However, findings provide little support for the reward deficit theory that postulates that individuals at risk for obesity show an initial hypo-responsivity of reward circuitry that motives overeating. Further, results provide support for the incentive sensitization and dynamic vulnerability theories that propose that overconsumption of high-calorie foods results in increased reward and attention region responsivity to cues that are associated with hedonic reward from intake of these high-calorie foods via conditioning, as well as a simultaneous decrease in reward region responsivity to high-calorie food tastes. However, there is little evidence that this induced reduction in reward region response to high-calorie food tastes drives an escalation in overeating. Finally, results provide support for the theory that an initial deficit in inhibitory control and a bias for immediate reward contribute to overconsumption of high-calorie foods. Findings imply that interventions that reduce reward and attention region responsivity to food cues and increase inhibitory control should reduce overeating and excessive weight gain, an intervention theory that is receiving support in randomized trials.

A low-cost open-architecture taste delivery system for gustatory fMRI and BCI experiments

BACKGROUND

Tasting is a complex process involving chemosensory perception and cognitive evaluation. Different experimental designs and solution delivery approaches may in part explain the variability reported in literature. These technical aspects certainly limit the development of taste-related brain computer interface devices.

NEW METHOD

We propose a novel modular, scalable and low-cost device for rapid injection of small volumes of taste solutions during fMRI experiments that gathers the possibility to flexibly increase the number of channels, allowing complex multi-dimensional taste experiments. We provide the full description of the hardware and software architecture and illustrate the application of the working prototype in single-subject event-related fMRI experiments by showing the BOLD responses to basic taste qualities and to five intensities of tastes during the course of perception.

RESULTS

The device is shown to be effective in activating multiple clusters within the gustatory pathway and a precise time-resolved event-related analysis is shown to be possible by the impulsive nature of the induced perception.

COMPARISON WITH EXISTING METHOD(S)

This gustometer represents the first implementation of a low-cost, easily replicable and portable device that is suitable for all kinds of fMRI taste experiments. Its scalability will boost the experimental design of more complex multi-dimensional fMRI studies of the human taste pathway.

CONCLUSIONS

The gustometer represents a valid open-architecture alternative to other available devices and its spread and development may contribute to an increased standardization of experimental designs in human fMRI studies of taste perception and pave the way to the development of novel taste-related BCIs.

Neural predictors of eating behavior and dietary change

Recently, there has been an increase in the number of human neuroimaging studies seeking to predict behavior above and beyond traditional measurements such as self-report. This trend has been particularly notable in the area of food consumption, as the percentage of people categorized as overweight or obese continues to rise. In this review, we argue that there is considerable utility in this form of health neuroscience, modeling the neural bases of eating behavior and dietary change in healthy community populations. Further, we propose a model and accompanying evidence indicating that several basic processes underlying eating behavior, particularly reactivity, regulation, and valuation, can be predictive of behavior change. We also discuss future directions for this work.

A narrative review of the construct of hedonic hunger and its measurement by the Power of Food Scale

INTRODUCTION

The term 'hedonic hunger' refers to one's preoccupation with and desire to consume foods for the purposes of pleasure and in the absence of physical hunger. The Power of Food Scale (PFS) was developed as a quantitative measure of this construct in 2009. Since then, over 50 published studies have used the PFS to predict appetite-related outcomes including neural, cognitive, behavioural, anthropometric and clinical measures.

OBJECTIVE

This narrative review evaluates how closely the PFS captures the construct it was originally presumed to assess and to more clearly define hedonic hunger itself.

METHODS

The measure's relationship to four domains is reviewed and summarized: motivation to consume palatable foods; level of actual consumption of such foods; body mass; and subjective loss-of-control over one's eating behaviour. Findings are synthesized to generate a more accurate understanding of what the PFS measures and how it may relate to the broader definition of hedonic hunger.

RESULTS

Results suggest that the PFS is closely related to motivation to consume palatable foods and, in extreme cases, occurrence of loss-of-control eating episodes. PFS scores are not consistently predictive of amount of food consumed or body mass.

CONCLUSIONS

Implications of these findings are discussed in the context of behavioural health, and avenues for further inquiry are identified.

Elevated Thalamic Response to High-Sugar Milkshake in Ethnic and Racial Minorities

In the USA, Hispanics and African-Americans show elevated obesity, yet little is known about possible ethnic/racial differences in brain response during intake of palatable foods. To examine potential differences between non-Hispanic white (nHW) and racial/ethnic minority individuals, we used functional magnetic resonance imaging (fMRI) to assess brain response to intake of eucaloric milkshakes that were either high-sugar or high-fat and a calorie-free, tasteless control solution. Our sample included healthy-weight adolescents who identified as African-American and/or Hispanic (minority, n = 27) and non-Hispanic white (nHW, n = 106). Minority participants showed elevated response in the pre-/postcentral gyrus, precuneus, and left thalamus in response to the high-sugar milkshake compared to high-fat milkshake. To confirm these effects were not driven by differences in body mass or a function of unequal cell sizes, we performed the same analyses in minority participants and a randomly selected subsample of nHW participants (n = 27) that were matched on BMI percentile. Similar to the full sample, we observed an elevated ventral posterior thalamic response to high-sugar milkshake in minority participants. This effect held after controlling for self-reported sugar and fat intake. These results suggest that African-American and Hispanic groups may have elevated response to specifically high-sugar foods in regions of the brain associated with sensory processing, providing novel information regarding the possible neural underpinnings of the disproportional risk for obesity seen in African-American and Hispanic populations.

Contextual factors associated with eating in the absence of hunger among adults with obesity

Eating in the absence of hunger (EAH) is under-explored in adults with obesity. In this study, 50 adults with obesity recorded eating episodes and theoretically-relevant environmental, perceptual, and emotional correlates in the natural environment for 2weeks via ecological momentary assessment (EMA). Generalized linear models and mixed models were used to characterize correlates and consequences of EAH vs. non-EAH episodes/tendencies (within-subjects and between-subjects effects, respectively), time of day, and time of day×EAH interactions. Approximately 21% of EMA-recorded eating episodes involved EAH, and 70% of participants reported at least 1 EAH episode. At the within-person level, participants' EAH episodes were associated with greater self-labeled overeating than their non-EAH episodes. At the between-person level, participants who tended to engage in more EAH reported less self-labeled overeating than those who engaged in less EAH. Across EAH and non-EAH episodes, eating in the evening was associated with overeating, expecting eating to be more rewarding, greater alcoholic beverage consumption, eating alone, eating because others are eating, and eating while watching television. Significant EAH×time of day interactions were also observed but the pattern of findings was not consistent. Findings suggest that EAH may be a relevant target for reducing food intake in individuals with obesity given its high prevalence and association with perceptions of overeating, although results should be extended using objective measures of food intake. Associations between evening eating episodes and perceptual and environmental factors should be further explored.

Reorganization of brain connectivity in obesity

Global brain connectivity (GBC) identifies regions of the brain, termed "hubs," which are densely connected and metabolically costly, and have a wide influence on brain function. Since obesity is associated with central and peripheral metabolic dysfunction we sought to determine if GBC is altered in obesity. Two independent fMRI data sets were subjected to GBC analyses. The first data set was acquired while participants (n = 15 healthy weight and 15 obese) tasted milkshake and the second with participants at rest (n = 33 healthy weight and 28 obese). In the resting state and during milkshake consumption GBC is consistently decreased in the ventromedial and ventrolateral prefrontal cortex, insula and caudate nucleus, and increased in brain regions belonging to the dorsal attention network including premotor areas, superior parietal lobule, and visual cortex. During milkshake consumption, but not at rest, additional decreases in GBC are observed in feeding-related circuitry including the insula, amygdala, anterior hippocampus, hypothalamus, midbrain, brainstem and somatomotor cortex. Additionally, GBC differences were not accounted for by age. These results demonstrate that obesity is associated with decreased GBC in prefrontal and feeding circuits and increased GBC in the dorsal attention network. We therefore conclude that global brain organization is altered in obesity to favor networks important for external orientation over those monitoring homeostatic state and guiding feeding decisions. Furthermore, since prefrontal decreases are also observed at rest in obese individuals future work should evaluate whether these changes are associated with neurocognitive impairments frequently observed in obesity and diabetes. Hum Brain Mapp 38:1403-1420, 2017. © 2016 Wiley Periodicals, Inc.

Hedonic Hunger Is Related to Increased Neural and Perceptual Responses to Cues of Palatable Food and Motivation to Consume: Evidence from 3 Independent Investigations

BACKGROUND

The Power of Food Scale (PFS) seeks to identify individuals who experience high appetitive drive in response to food cues, which is a construct termed "hedonic hunger."

OBJECTIVE

The purpose of this study was to assess cross-sectional correlates and predictive power of PFS scores to probe the construct of hedonic hunger.

METHODS

Separate data from 3 studies (study 1, n = 44; study 2, n = 398; study 3, n = 100) were used to evaluate the construct of hedonic hunger. We examined the correlations between the PFS and neural responsivity during intake and anticipated intake of palatable foods, behavioral food reinforcement, perceptual hedonic ratings of food images, and change in body mass index (BMI) and binge eating over time.

RESULTS

Hedonic hunger was strongly related to bilateral brain response in regions implicated in oral somatosensory processing during cue-elicited anticipation of food intake (study 1; right postcentral gyrus: r = 0.67, P < 0.001; left postcentral gyrus: r = 0.64, P < 0.001), and was correlated with behavioral food reinforcement (study 2; r = 0.31, P = 0.03) and perceptual hedonic ratings (study 3; r = 0.24, P = 0.02). Hedonic hunger was not associated with baseline BMI (studies 1-3: P = 0.14, 0.21, and 0.37, respectively) or change in BMI over the 2-y follow-up (studies 1 and 2: P = 0.14 and 0.37, respectively) but was significantly correlated with baseline binge eating in 2 samples (study 1: r = 0.58, P = 0.001; study 2: r = 0.31, P = 0.02; and study 3: P = 0.02).

CONCLUSIONS

Hedonic hunger was not predictive of weight regulation. However, individuals who report high hedonic hunger are likely to show increased neural and perceptual responses to cues of palatable foods, increased motivation to consume such foods, and a greater likelihood of current binge eating.

Power of Food Scale in association with weight outcomes and dieting in a nationally representative cohort of U.S. young adults

Food reward sensitivity may influence susceptibility to overeating in a permissive food environment, contributing to unintended weight gain and intentional weight loss behavior. This study examined associations of food reward sensitivity, assessed by the Power of Food Scale (PFS), with weight outcomes and dieting in a nationally representative cohort of U.S. emerging adults. Wave 5 (W5, 5th year of follow-up) respondents from the NEXT Generation Health Study were included (N = 2202, W5 age = 20.3 ± 0.02 years). Baseline and W5 BMI, W5 weight status (normal weight = 18.5 ≤ BMI < 25, overweight = 25 ≤ BMI < 30, obese = BMI ≥ 30), BMI change (W5-baseline BMI) and onset of overweight or obesity (OWOB) were calculated from self-reported height and weight. PFS (aggregate and 3 domain scores: food available, present, and tasted) and dieting for weight-loss were assessed at W5. Adjusted linear regressions estimated associations of PFS with W5 BMI and BMI change. Log-binomial regressions estimated associations of high W5 BMI (≥25), OWOB onset and dieting with PFS. Post hoc analyses estimated associations of PFS with W5 perceived weight status (overweight vs. about right or underweight). W5 BMI = 25.73 ± 0.32 kg/m(2), and OWOB onset occurred in 27.7% of participants. The PFS-food available score was associated with BMI change, β ± SE = 0.41 ± 0.19. Other PFS scores were not associated with weight outcomes. Dieting prevalence was higher in participants with high versus low W5 BMI (61% versus 32%), and was positively associated with all PFS scores except the PFS-food tasted score, e.g., relative risk (RR) of dieting for PFS-aggregate = 1.13, 95%CI [1.01-1.26]. Post-hoc analyses indicated perceived overweight was positively associated with PFS-food available, 1.12, [1.01-1.24], and PFS-food present, 1.13, [1.03-1.24]. PFS was positively related to dieting and perceived overweight, but not concurrent or change in weight status in a representative cohort of U.S. emerging adults.

Neural vulnerability factors that increase risk for future weight gain

Theorists have proposed several neural vulnerability factors that may increase overeating and consequent weight gain. Early cross-sectional imaging studies could not determine whether aberrant neural responsivity was a precursor or consequence of overeating. However, recent prospective imaging studies examining predictors of future 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. The present article 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 5 neural vulnerability theories for excessive weight gain. Extant 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. However, existing data provide only minimal support for the reward deficit theory. Findings are synthesized into a new working etiologic model that is based on current scientific knowledge. Important directions for future studies, which have the potential to support or refute this working etiologic model, are delineated. (PsycINFO Database Record

Neural systems implicated in obesity as an addictive disorder: from biological to behavioral mechanisms

Contributing factors to obesity have been identified, yet prevention and treatment efforts have had limited long-term success. It has recently been suggested that some individuals may experience an addictive-like response to certain foods, such as losing control over consumption and continued consumption despite negative consequences. In support, shared biological and behavioral features seem to exist between "food addiction" and traditional substance-use disorders. "Food addiction" may be another important contributor to obesity. The current chapter reviews existing literature regarding neural systems implicated similarly in obesity and addiction, discusses unique considerations for addictive-like eating, and proposes directions for future research regarding "food addiction" as an emerging construct for addiction medicine.

A potential role for the midbrain in integrating fat-free mass determined energy needs: An H2 (15) O PET study

Little is known on how sensing of energy needs is centrally represented, integrated, and translated into the behavioral aspects of energy homeostasis. Fat free mass (FFM) is the major determinant of energy expenditure. We investigated how interindividual variances in FFM relate to neuronal activity in humans. Healthy adults (n = 64, 21F/43M; age 31.3 ± 9.1y; percentage of body fat [PFAT] 25.6 ± 10.7%; BMI 30.4 ± 9) underwent a 36h fast and subsequent H(2) (15) O positron emission tomographic (PET) measurement of regional cerebral blood flow (rCBF). Multiple variable regression analysis revealed significant associations of FFM with rCBF within the midbrain [including parts of the periaqueductal gray (PAG), ventral tegmental area (VTA), thalamic and hypothalamic regions], the bilateral parahippocampal region, left anterior cingulate, left insular cortex, right cerebellum, and distinct regions within the temporal and occipital cortex. In contrast, no significant associations were found for fat mass (FM). We investigated the potential functional-anatomical link between FFM and central regulation of food intake by performing a conjunction analysis of FFM and the perceived hunger feelings. This showed a significant overlap within the midbrain PAG. Mediation analysis demonstrated a significant indirect effect of FFM on hunger with PAG rCBF as mediator. Most regions we found to be associated with FFM form part in ascending homeostatic pathways and cortical circuitries implicated in the regulation of basic bodily functions indicating a potential role of these central networks in the integration of FFM determined energy needs.

Opposing relationships of BMI with BOLD and dopamine D2/3 receptor binding potential in the dorsal striatum

Findings from clinical and preclinical studies converge to suggest that increased adiposity and/or exposure to a high fat diet are associated with alterations in dorsal striatal (DS) circuitry. In humans there is a reliable inverse relationship between body mass index (BMI) and response to palatable food consumption in the dorsal striatum (DS). Positron emission tomography (PET) studies also suggest altered DS dopamine type 2/3 receptor (D2R/D3R) availability in obesity; however, the direction of the association is unclear. It is also not clear whether dopamine receptor levels contribute to the lower blood oxygen level dependent (BOLD) response because PET studies have targeted the morbidly obese and, functional magnetic resonance imaging (fMRI) studies rarely include individuals with BMIs in this range. Therefore we examined whether the fMRI BOLD response in the DS to milkshake is associated with D2R/D3R availability measured with [(11) C]PHNO and PET in individuals with BMI ranging from healthy weight to moderately obese. Twenty-nine subjects participated in the fMRI study, 12 in the [(11) C]PHNO PET study, 8 of whom also completed the fMRI study. As predicted there was a significant negative association between DS BOLD response to milkshake and BMI. In contrast, BMI was positively associated with D2R/D3R availability. Dorsal striatal BOLD response was unrelated to D2R/D3R availability. Considered in the context of the larger literature our results suggest the existence of a non-linear relationship between D2R/D3R availability and BMI. Additionally, the altered BOLD responses to palatable food consumption observed in obesity are not clearly related to D2R/D3R receptor availability. Using [(11) C]PHNO and PET brain imaging techniques we show that body mass index was positively associated with D2R/D3R availability in the dorsal striatum, but that functional MR BOLD response was unrelated to D2R/D3R availability. These results suggest the existence of a nonlinear relationship between D2R/D3R availability and body mass index and that the altered BOLD responses to food consumption seen in obesity are not directly related to D2R/D3R availability.

Increased brain response to appetitive tastes in the insula and amygdala in obese compared with healthy weight children when sated

Objective

There is evidence of altered neural taste response in female adolescents who are obese, and in adolescents who are at risk for obesity. To further understand risk factors for the development of overeating and obesity, we investigated response to tastes of sucrose and water in 23 obese and healthy weight children.

Methods and design

Thirteen healthy weight (HW) and 10 obese (OB) 8–12 year old children underwent functional magnetic resonance imaging while tasting sucrose and water. Additionally, children completed an eating in the absence of hunger paradigm and a sucrose liking task.

Results

A region of interest analysis revealed an elevated BOLD response to taste (sucrose and water) within the bilateral insula and amygdala in OB children relative to HW children. Whole brain analyses revealed a group by condition interaction within the paracingulate, medial frontal, middle frontal gyri, and right amygdala: post hoc analyses suggested an increased response to sucrose for OB relative to HW children, whereas HW children responded more strongly to water relative to sucrose. In addition, OB children, relative to HW, tended to recruit the right putamen as well as medial and lateral frontal and temporal regions bilaterally.

Conclusion

This study showed increased reactivity in the amygdala and insula in the OB compared to HW children, but no functional differentiation in the striatum, despite differences in the striatum previously seen in older samples. These findings support the concept of the association between increased neural processing of food reward in the development of obesity, and raise the possibility that emotional and interoceptive sensitivity could be an early vulnerability in obesity.

The effects of energy balance, obesity-proneness and sex on the neuronal response to sweet taste

We have previously shown that propensity for weight gain, energy balance state and sex are important determinants of the neuronal response to visual food cues. It is not clear, though, whether these factors also impact the neuronal response to taste. The objective of this study was to examine the neuronal response to sweet taste during energy imbalance in men and women recruited to be obesity-prone (OP) or obesity-resistant (OR). OP (13 men and 12 women) and OR (12 men and 12 women) subjects were studied after 1 day of eucaloric, overfed and underfed conditions in a randomized crossover design. On each test day, fMRI was performed in the respective acute fed state while subjects received in random order 60 trials each of 1M sucrose solution (SU), or artificial saliva (AS) following a visual cue predicting the taste. The neuronal response to SU versus AS expectation was significantly greater in the amygdala, orbitofrontal cortex, putamen and insula in OR versus OP; SU receipt was not different between groups. There were also sex-based differences with men having greater neuronal response to SU versus AS receipt in the caudate than women. The results, however, were not impacted by the state of energy balance. In summary, response to expectation but not receipt of basic sweet taste was different in OR compared to OP, highlighting the importance of learning and conditioning in the propensity to gain weight. Response to sucrose taste receipt was stronger in men than women, raising questions about the effect of sex hormones on brain response to food.

A functional neuroimaging review of obesity, appetitive hormones and ingestive behavior

Adequate energy intake is vital for the survival of humans and is regulated by complex homeostatic and hedonic mechanisms. Supported by functional MRI (fMRI) studies that consistently demonstrate differences in brain response as a function of weight status during exposure to appetizing food stimuli, it has been posited that hedonically driven food intake contributes to weight gain and obesity maintenance. These food reward theories of obesity are reliant on the notion that the aberrant brain response to food stimuli relates directly to ingestive behavior, specifically, excess food intake. Importantly, functioning of homeostatic neuroendocrine regulators of food intake, such as leptin and ghrelin, are impacted by weight status. Thus, data from studies that evaluate the effect on weight status on brain response to food may be a result of differences in neuroendocrine functioning and/or behavior. In the present review, we examine the influence of weight and weight change, exogenous administration of appetitive hormones, and ingestive behavior on BOLD response to food stimuli.

Neural responsivity during soft drink intake, anticipation, and advertisement exposure in habitually consuming youth

OBJECTIVE

Although soft drinks are heavily advertised, widely consumed, and have been associated with obesity, little is understood regarding neural responsivity to soft drink intake, anticipated intake, and advertisements.

DESIGN AND METHODS

Functional MRI was used to assess examine neural response to carbonated soft drink intake, anticipated intake and advertisement exposure as well as milkshake intake in 27 adolescents that varied on soft drink consumer status.

RESULTS

Intake and anticipated intake of carbonated Coke® activated regions implicated in gustatory, oral somatosensory, and reward processing, yet high-fat/sugar milkshake intake elicited greater activation in these regions vs. Coke intake. Advertisements highlighting the Coke product vs. nonfood control advertisements, but not the Coke logo, activated gustatory and visual brain regions. Habitual Coke consumers vs. nonconsumers showed greater posterior cingulate responsivity to Coke logo ads, suggesting that the logo is a conditioned cue. Coke consumers exhibited less ventrolateral prefrontal cortex responsivity during anticipated Coke intake relative to nonconsumers.

CONCLUSIONS

Results indicate that soft drinks activate reward and gustatory regions, but are less potent in activating these regions than high-fat/sugar beverages, and imply that habitual soft drink intake promotes hyper-responsivity of regions encoding salience/attention toward brand specific cues and hypo-responsivity of inhibitory regions while anticipating intake.

Relative ability of fat and sugar tastes to activate reward, gustatory, and somatosensory regions

BACKGROUND

Although the intake of high-fat and high-sugar food activates mesolimbic reward, gustatory, and oral somatosensory brain regions, contributing to overeating, few studies have examined the relative role of fat and sugar in the activation of these brain regions, which would inform policy, prevention, and treatment interventions designed to reduce obesity.

OBJECTIVE

We evaluated the effect of a high-fat or high-sugar equicaloric chocolate milkshake and increasing fat or sugar milkshake content on the activation of these regions.

DESIGN

Functional magnetic resonance imaging was used to assess the neural response to the intake of high-fat/high-sugar, high-fat/low-sugar, low-fat/high-sugar, and low-fat/low-sugar chocolate milkshakes and a tasteless solution in 106 lean adolescents (mean ± SD age = 15.00 ± 0.88 y). Analyses contrasted the activation to the various milkshakes.

RESULTS

High-fat compared with high-sugar equicaloric milkshakes caused greater activation in the bilateral caudate, postcentral gyrus, hippocampus, and inferior frontal gyrus. High-sugar compared with high-fat equicaloric milkshakes caused greater activation in the bilateral insula extending into the putamen, the Rolandic operculum, and thalamus, which produced large activation regions. Increasing sugar in low-fat milkshakes caused greater activation in the bilateral insula and Rolandic operculum; increasing fat content did not elicit greater activation in any region.

CONCLUSIONS

Fat caused greater activation of the caudate and oral somatosensory regions than did sugar, sugar caused greater activation in the putamen and gustatory regions than did fat, increasing sugar caused greater activity in gustatory regions, and increasing fat did not affect the activation. Results imply that sugar more effectively recruits reward and gustatory regions, suggesting that policy, prevention, and treatment interventions should prioritize reductions in sugar intake. This trial was registered at clinicaltrials.gov as DK092468.

Appetitive traits from infancy to adolescence: using behavioral and neural measures to investigate obesity risk

We come into the world with enduring predispositions towards food, which interact with environmental factors to influence our eating behaviors and weight trajectories. But our fates are not sealed - by learning more about this process we can identify ways to intervene. To advance this goal this we need to be able to assess appetitive traits such as food cue responsiveness and satiety sensitivity at different developmental stages. Assessment methods might include behavioral measures (e.g. eating behavior tests, psychometric questionnaires), but also biomarkers such as brain responses to food cues measured using fMRI. Evidence from infants, children and adolescents suggests that these indices of appetite differ not only with body weight, but also with familial obesity risk as assessed by parent weight, which reflects both genetic and environmental influences, and may provide a useful predictor of obesity development. Behavioral and neural approaches have great potential to inform each other: examining eating behavior can help us identify meaningful appetitive endophenotypes whose neural bases can be probed, while increasing knowledge of the shared neurobiology underlying appetite, obesity, and related behaviors and disorders may ultimately lead to innovative generalized interventions. Another challenge will be to combine comprehensive behavioral and neural assessments of appetitive traits with measures of relevant genetic and environmental factors within long-term prospective studies. This approach may help to identify the biobehavioral precursors of obesity, and lay the foundations for targeted neurobehavioral interventions that can interrupt the pathway to excess weight.

Sociocultural pressures and adolescent eating in the absence of hunger

Parental feeding practices and sociocultural pressures theoretically influence eating behavior. Yet, whether these factors relate to eating in the absence of hunger (EAH) is unknown. We assessed if sociocultural pressures were associated with EAH among 90 adolescents (Mage=15.27, SD=1.39; 48% female). Parents completed the Child Feeding Questionnaire. Adolescents completed the Perceived Sociocultural Pressures Scale, Sociocultural Attitudes Towards Appearance Questionnaire-3, and Multidimensional Body Self-Relations Questionnaire-Appearance Scales. On two occasions, EAH was assessed as snack food intake after adolescents ate to satiety. Controlling for body composition and demographics, parental restriction and family pressure to be thin were associated with greater EAH. Media pressure was related to more EAH in girls. Appearance orientation and preoccupation with becoming overweight mediated links between sociocultural pressures and EAH. Findings support the notion that sociocultural pressures and their links to body image may contribute to the course of disinhibited eating behaviors during adolescence.