How is reward sensitivity related to bodyweight in children?

Smaller subcortical volume relates to greater weight gain in girls with initially healthy weight

OBJECTIVE

Among 3614 youth who were 9 to 12 years old and initially did not have overweight or obesity (12% [n = 385] developed overweight or obesity), we examined the natural progression of weight gain and brain structure development during a 2-year period with a high risk for obesity (e.g., pre- and early adolescence) to determine the following: 1) whether variation in maturational trajectories of the brain regions contributes to weight gain; and/or 2) whether weight gain contributes to altered brain development.

METHODS

Data were gathered from the Adolescent Brain Cognitive Development (ABCD) Study. Linear mixed-effects regression models controlled for puberty, caregiver education, handedness, and intracranial volume (random effects: magnetic resonance scanner [MRI] scanner and participant). Because pubertal development occurs earlier in girls, analyses were stratified by sex.

RESULTS

For girls, but not boys, independent of puberty, greater increases in BMI were driven by smaller volumes over time in the bilateral accumbens, amygdala, hippocampus, and thalamus, right caudate and ventral diencephalon, and left pallidum (all p < 0.05).

CONCLUSIONS

The results suggest a potential phenotype for identifying obesity risk because underlying differences among regions involved in food intake were related to greater weight gain in girls, but not in boys. Importantly, 2 years of weight gain may not be sufficient to alter brain development, highlighting early puberty as a critical time to prevent negative neurological outcomes.

The qualitative evaluation of food addiction across the lifespan

Although it remains controversial, food addiction (FA) research has expanded substantially and empirical evidence for FA is growing. While quantitative studies have explored the prevalence and correlates of FA during childhood and adolescence, little is known about the perceived lived experience of FA across the lifespan, nor how experiences and perceptions of FA may change over time. For this study, 16 participants who met symptom threshold criteria for FA on the Yale Food Addiction Scale 2.0 completed in-depth, semi-structured qualitative interviews focused on their perceptions of the development of FA overtime, and perceived risk and protective factors. Thematic analysis was used to develop themes about the lived experience of FA in childhood, adolescence, and adulthood. Overall, highly palatable foods were viewed as the most problematic, while minimally processed foods were less associated with impairment and distress. Themes in childhood included a strong desire for highly processed foods and the perception that parental control over food choices could be either protective or risky for the later development of FA depending on which foods were available at home. In adolescence and young adulthood, increasing autonomy over food choices and the high availability of highly processed foods in the college environment were viewed as risk factors. Additionally, weight gain was a prominent theme. Finally, adulthood was characterized by more severe manifestations of FA, and the stress of adult responsibilities (e.g., work, parenting) contributed to this perception. This research sets the stage for future quantitative studies to explore these novel findings at the population level.

Brain dopamine receptor system is not altered in obesity: Bayesian and frequentist meta-analyses

Feeding induces dopamine release in the striatum, and a dysfunction of the dopaminergic reward system can lead to overeating, and obesity. Studies have reported inconsistent findings of dopamine receptor (DR) positron emission tomography scans in obesity. Here we investigated the association between DR availability and overweight/obesity using Bayesian and frequentist meta-analysis. We performed a systematic search of Embase, Medline, Scopus and Web of Science for studies that compared striatal DR availability between lean subjects and overweight/obese subjects. The standardized mean difference (Hedge's g) of DR availability was calculated after extraction of data from each study. Studies were divided into two groups according to the definition of overweight/obese subjects (body mass index [BMI] cutoff of 25 and 30 kg/m2 ). Both Bayesian and frequentist meta-analysis was done in R Statistical Software version 4.2.2 (The R Foundation for Statistical Computing). Nine studies were eligible for inclusion in this study. Three studies with C11-raclopride, one with C11-PNHO, two with F18-fallypride, one with I123-IBZM, one with C11-NMB and one with both C11-raclopride and C11-PNHO were included. In Bayesian meta-analysis, the standardized mean difference of DR availability between lean and overweight/obese subjects markedly overlapped with zero regardless of BMI cutoff for obesity. In frequentist meta-analysis, the pooled standardized mean difference of DR availability did not show the significant difference between lean and overweight/obese subjects. There was an effect of the radiopharmaceutical on the standardized mean difference of DR availability in meta-analysis of BMI cutoff of 25 kg/m2 . In conclusion, brain DR availability is not different between lean and overweight/obese subjects. However, the effect is dependent on the radiopharmaceutical and the degree of obesity. Further studies with multi-radiopharmaceutical in the same individuals are needed to understand the association between DR and obesity.

Child-reported vegetable neophobia is associated with risk avoidance for distaste in children aged 4-15 years

Children who are food neophobic and/or picky eaters often refuse intake of especially fruits and vegetables, thereby narrowing their dietary variety and impairing the quality of their food intake. In this preregistered study, we investigated whether picky eating and food neophobia are related to bitter taste sensitivity (PROP taster status) and risk avoidance for distaste. A total of 367 children (201 girls; M age = 8.7 years, range: 4-15 years) participated in the study. They completed the vegetable neophobia subscale of the fruit and vegetable neophobia instrument (FVNI). A caregiver completed the child food rejection scale (CFRS), a parent-report measure of food neophobia and picky eating. Children's bitter taste sensitivity was measured with a PROP (6-n-propylthiouracil) taste strip, and the children completed a modified Children's Gambling Task (Candy Gambling Game) to measure risk avoidance for distaste. In this task, children could select cards from a risky deck (chance of winning two tasty cherry-flavoured jelly beans, but also the risk of getting a distasteful soap-flavoured jelly bean) or a safe deck (chance of winning one tasty jelly bean or no jelly bean). The results show that picky eating and food neophobia (either parent- or self-reported) are not related to PROP taster status. However, children who self-reported higher levels of vegetable neophobia showed less risky choice behaviour in the Candy Gambling Game, although this relationship was not found with parent-reported food neophobia. We conclude that risk avoidance for distaste, but not taste function, is associated with children's self-reported food rejection tendencies. To broaden the food repertoire of children high in food neophobia, it might be useful to reduce the perceived risk of distaste, when introducing a novel food or meal.

Reward and inhibition in obesity and cigarette smoking: Neurobiological overlaps and clinical implications

Cigarette smoking and obesity are the leading causes of premature morbidity and mortality and increase the risk of all-cause mortality four-fold when comorbid. Individuals with these conditions demonstrate neurobiological and behavioral differences regarding how they respond to rewarding stimuli or engage in inhibitory control. This narrative review examines the role of reward and inhibition in cigarette smoking and obesity independently, as well as recent research demonstrating an effect of increased body mass index (BMI) on neurocognitive function in individuals who smoke. It is possible that chronic smoking and overeating of highly palatable food, contributing to obesity, dysregulates reward neurocircuitry, subsequently leading to hypofunction of brain networks associated with inhibitory control. These brain changes do not appear to be specific to food or nicotine and, as a result, can potentiate continued cross-use. Changes to reward and inhibitory function due to increased BMI may also make cessation more difficult for those comorbid for obesity and smoking.

Dopamine receptor and dopamine transporter in obesity: A meta-analysis

The brain plays a major role in controlling the desire to eat. This meta-analysis aimed to assess the association between dopamine receptor (DR) availability and dopamine transporter (DAT) availability, measured using positron emission tomography, and obesity. We performed a systematic search of MEDLINE (from inception to November 2020) and EMBASE (from inception to November 2020) for articles published in English using the keywords "dopamine receptor," "dopamine transporter," "obesity," and "neuroimaging." Body mass index (BMI) and the corresponding binding potential (BP_ND ) were extracted from figures in each study using Engauge Digitizer, version 12.1, and plotted for radiopharmaceuticals and regions of interest (ROIs). Five studies involving 119 subjects with DR and five studies including 421 subjects with DAT were eligible for inclusion in this study. In overweight or obese subjects with BMI of 25 kg/m² or higher, DR availability from ¹¹ C-Racloprie was negatively associated with BMI. However, DR availability from ¹¹ C-PHNO was positively associated with BMI. DAT ratio was calculated after dividing DAT availabilities of overweight/obese BMI with mean DAT availabilities of normal BMI. The association between DAT ratio and BMI was not significant regardless of radiopharmaceuticals. In conclusion, dopamine plays a main role in the reward system with regard to obesity. Overweight and obese subjects had negative association between DR availability from ¹¹ C-Raclopride and BMI. However, the association of DR availability with BMI was dependent on radiopharmaceuticals. DAT availability did not show the significant relationship with BMI regardless of radiopharmaceuticals.

Bidirectional associations between parental feeding practices, infant appetitive traits and infant BMIz: a longitudinal cohort study

BACKGROUND

Little is known about the pathways linking parent feeding practices with appetitive traits and BMIz throughout infancy. This study examined bidirectional associations between parental feeding practices, infant appetitive traits, and infant BMIz.

METHODS

Parents (n = 380) of infants aged less than 6 months at baseline reported their feeding practices (using the Feeding Practices and Structure Questionnaire (FPSQ) for infants and toddlers), infant appetitive traits (using the Baby Eating Behaviour Questionnaire) and infant BMIz (parent-reported) at three timepoints (< 6 months, ~ 9 months, ~ 12 months) up to 12 months of age. Cross-lagged models examined bidirectional associations between parent feeding practices, infant appetitive traits and infant BMIz.

RESULTS

There was strong continuity across the three timepoints for maternal feeding practices, infant appetitive traits, and infant BMIz. Infant food avoidance was prospectively associated with higher parental persuasive feeding. Infant BMIz was prospectively associated with higher parent-led feeding. Parent use of food to calm was prospectively associated with lower infant BMIz, and infant BMIz was prospectively associated with higher infant food approach. Feeding on demand was prospectively associated with lower infant food approach.

CONCLUSION

This study highlights the complex associations between parental feeding practices, infant appetitive traits and infant BMIz. The study demonstrated that both child and parent effects are important, suggesting a need for tailored programs beginning in infancy to promote and support infant appetitive traits and parent feeding practices that support healthy development.

The reward and punishment responsivity and motivation questionnaire (RPRM-Q): A stimulus-independent self-report measure of reward and punishment sensitivity that differentiates between responsivity and motivation

Reward and punishment sensitivity seem important traits in understanding behavior in general and psychopathology in particular. Though the definitions used for reward and punishment sensitivity differentiate between responsivity and motivation, the measures thus far used to assess these constructs do not. Further, specificity of the type of reward (e.g., drugs) and punishment (e.g., spiders) in questionnaires might result in measurement bias especially when examining the relationship with psychopathology. Therefore, we developed a stimulus-independent multidimensional questionnaire of reward and punishment sensitivity that differentiates between responsivity and motivation. This study addresses the psychometric qualities of this newly developed reward and punishment responsivity and motivation questionnaire (RPRM-Q). On the basis of exploratory ordinal factor analysis (N = 273) that was used to examine the quality of the initial pool of 39 items, the number of items was reduced to 18. Confirmatory ordinal factor analysis on the remaining items in an independent sample (N = 328) supported a 18-item four-factor model, and showed acceptable to good internal reliability. The relationship between the subscales of the RPRM-Q and often used questionnaires was examined in the combined sample (N = 601), which showed some first support for the ability of the new questionnaire to differentiate between responsivity and motivation to approach/avoid. The findings indicate that the RPRM-Q might be a helpful instrument to further test the relevance of punishment and reward sensitivity in psychopathology.

Hypothesizing in the Face of the Opioid Crisis Coupling Genetic Addiction Risk Severity (GARS) Testing with Electrotherapeutic Nonopioid Modalities Such as H-Wave Could Attenuate Both Pain and Hedonic Addictive Behaviors

In the United States, amid the opioid overdose epidemic, nonaddicting/nonpharmacological proven strategies are available to treat pain and manage chronic pain effectively without opioids. Evidence supporting the long-term use of opioids for pain is lacking, as is the will to alter the drug-embracing culture in American chronic pain management. Some pain clinicians seem to prefer classical analgesic agents that promote unwanted tolerance to analgesics and subsequent biological induction of the "addictive brain". Reward genes play a vital part in modulation of nociception and adaptations in the dopaminergic circuitry. They may affect various sensory and affective components of the chronic pain syndromes. The Genetic Addiction Risk Severity (GARS) test coupled with the H-Wave at entry in pain clinics could attenuate pain and help prevent addiction. The GARS test results identify high-risk for both drug and alcohol, and H-Wave can be initiated to treat pain instead of opioids. The utilization of H-Wave to aid in pain reduction and mitigation of hedonic addictive behaviors is recommended, notwithstanding required randomized control studies. This frontline approach would reduce the possibility of long-term neurobiological deficits and fatalities associated with potent opioid analgesics.

Subtyping youngsters with obesity: A theory-based cluster analysis

Psychological mechanisms play a crucial role in explaining weight gain. Aim of the present study was to identify subtypes in youngsters with obesity in line with these mechanisms. Defining homogeneous clusters within this heterogeneous group provides relevant information for personalized treatments. Data were collected in N = 572 participants (51% boys, aged 7-19) with extreme obesity (%BMI M = 187.8; SD = 30.9) recruited in an inpatient treatment centre. Based on psychological models of overweight/obesity, the Affect Regulation Model, the Reward Deficiency Model and The Dual Pathway Model, cluster variables were selected assessing emotional eating, reward reactivity and regulative capacities. Youngsters reported on emotional eating (DEBQ Emotional Eating) and reward sensitivity (BAS), while parents reported on children's regulative Executive Functions (BRIEF). Characteristics of the different clusters were examined concerning weight variables (pre and post treatment) and variables indexing problematic eating (DEBQ External Eating, Ch-EDE), affect regulation (FEEL-KJ) and depressive symptoms (CDI). Hierarchical cluster analyses supported the presence of three clusters, further evaluated by K-means cluster analyses. The cluster solutions differed according to age and sex (boys 7-13, boys 14-19, girls 7-13, girls 14-19). In all four age and gender subsamples, an "Emotional Eating" cluster displaying a vulnerable profile (high depression, maladaptive emotion regulation, problematic eating) and a "Reward Deficiency" cluster displaying a more resilient profile were detected. In girls 7-13, a "Weak Executive Functioning" indicative of insufficient self-regulative capacities, showed moderate to high emotional problems and problematic eating. In the other subgroups, the "Mean Level Functioning" cluster also showed elevated emotional problems and problematic eating. Given that different clusters can be identified, and given that these clusters have different profiles on emotional problems and problematic eating, subtyping youngsters with severe obesity is indicated, setting the stage for personalized treatments.

The Behavioral Inhibition System/Behavioral Activation System Scales: Measurement Invariance Across Gender in Chinese University Students

Objectives: To identify the optimal factor structure of the behavioral inhibition system/behavioral activation system (BIS/BAS) scales and to examine measurement invariance (MI) of the scales across gender among a sample of Chinese undergraduate students. Methods: Convenience sampling was employed to recruit 1,085 subjects. Participants completed the Chinese version of the BIS/BAS scales. A confirmatory factor analysis (CFA) of competing models was conducted to determine the optimal factor model, followed by a test of MI across gender based on the optimal model. Results: A single-group CFA indicated that the modified four-factor structure fits best in the total sample. Multiple-group CFAs demonstrated that configural invariance, weak invariance, strong invariance, and strict invariance models of the four-factor structure of the BIS/BAS scales were all acceptable. Conclusion: The four-factor structure of the Chinese version of the BIS/BAS scales possesses MI across gender.

Appetitive behaviors and body composition in school-age years: Bi-directional analyses in a population-based birth cohort

Cross-sectional studies have consistently associated appetitive behaviors with child body mass index. However, few prospective studies have investigated the association between appetite and other measures of body composition and its directionality. We aimed to investigate the bi-directional relationship between appetitive behaviors and body composition in school-aged children. Data from 3668 children of the Generation XXI birth cohort were analyzed. Appetitive behaviors were assessed at 7 and 10 years through the Children's Eating Behavior Questionnaire. Higher fat mass and fat-free mass were measured through tetrapolar bioelectric impedance and waist-to-weight and waist-to-height ratios were calculated. Fat and fat-free mass indexes, waist-to-weight and waist-to-height age- and sex-specific z-scores were then calculated. Cross-lagged analyses were performed (body composition at 7 to appetitive behaviors at 10 and the reverse) to measure the magnitude and direction of associations. Fat mass and waist-to-height ratio at 7y predicted greater food approach behaviors at 10y (Enjoyment of Food, Food Responsiveness, Desire to Drink and Emotional Overeating), but not waist-to-weight, which seems to be consequence of child's avid appetite (e.g. Enjoyment of Food at 7y: β_standardized = 0.085, 95%CI = 0.041; 0.128, p < 0.001). Child scores on food avoidant behaviors, such as Satiety Responsiveness (β_standardized = -0.073, 95%CI = -0.110;-0.034, p < 0.001) and Slowness in Eating (β_standardized = -0.080, 95% CI = -0.120;-0.041, p < 0.001) at 7y predicted lower fat-free mass at 10. Appetitive behaviors may not solely predict weight status, but the path of association between body composition and later appetitive behavior may also be true, especially for food approaching behaviors and adipose tissue. Interventions aiming to prevent excess weight should focus on appetitive behaviors. Moreover, in children with higher adiposity, other pathways also seem to regulate appetite and need to be considered in interventions.

Childhood Obesity, Cortical Structure, and Executive Function in Healthy Children

The development of executive function is linked to maturation of prefrontal cortex (PFC) in childhood. Childhood obesity has been associated with changes in brain structure, particularly in PFC, as well as deficits in executive functions. We aimed to determine whether differences in cortical structure mediate the relationship between executive function and childhood obesity. We analyzed MR-derived measures of cortical thickness for 2700 children between the ages of 9 and 11 years, recruited as part of the NIH Adolescent Brain and Cognitive Development (ABCD) study. We related our findings to measures of executive function and body mass index (BMI). In our analysis, increased BMI was associated with significantly reduced mean cortical thickness, as well as specific bilateral reduced cortical thickness in prefrontal cortical regions. This relationship remained after accounting for age, sex, race, parental education, household income, birth-weight, and in-scanner motion. Increased BMI was also associated with lower executive function. Reduced thickness in the rostral medial and superior frontal cortex, the inferior frontal gyrus, and the lateral orbitofrontal cortex partially accounted for reductions in executive function. These results suggest that childhood obesity is associated with compromised executive function. This relationship may be partly explained by BMI-associated reduced cortical thickness in the PFC.

Moderating Effects of Parental Feeding Practices and Emotional Eating on Dietary Intake among Overweight African American Adolescents

This study examined the effects of parental feeding practices and adolescent emotional eating (EE) on dietary outcomes among overweight African American adolescents. Based on Family Systems Theory, it was hypothesized that parental feeding practices, such as parental monitoring and responsibility, would buffer the effects of EE on poor dietary quality, whereas practices such as concern about a child’s weight, restriction, and pressure-to-eat would exacerbate this relationship. Adolescents (N = 127; Mage = 12.83 ± 1.74; MBMI% = 96.61 ± 4.14) provided baseline data from the Families Improving Together (FIT) for Weight Loss trial and an ancillary study. Dietary outcomes (fruit and vegetables (F&Vs), energy intake, sweetened beverage, total fat, and saturated fat) were assessed using random 24-h dietary recalls. Validated surveys were used to assess adolescent-reported EE and parental feeding practices. Results demonstrated a significant interaction between EE and parental monitoring (adjusted analyses; B = 0.524, SE = 0.176, p = 0.004), restriction (B = −0.331, SE = 0.162, p = 0.043), and concern (B = −0.602, SE = 0.171, p = 0.001) on F&V intake; under high monitoring, low restriction, and low concern, EE was positively associated with F&V intake. There were no significant effects for the other dietary outcomes. These findings indicate that parental feeding practices and EE may be important factors to consider for dietary interventions, specifically for F&V intake, among overweight African American adolescents.

Why Dieters Succeed or Fail: The Relationship Between Reward and Punishment Sensitivity and Restrained Eating and Dieting Success

BACKGROUND

The current study set out to improve our understanding of the characteristics of individuals who are motivated to restrict their food intake yet who nevertheless fail to do so. We examined whether punishment sensitivity (PS) was related to restrained eating, and reward sensitivity (RS) to perceived dieting success. Additionally, it was examined whether executive control (EC) moderates the association between RS and perceived dieting success.

METHODS

Female student participants (N = 290, aged 17-29, BMI between 18.5 and 38.0) completed questionnaires on restrained eating, perceived dieting success, RS and PS, and carried out a behavioral task to index EC.

RESULTS

PS was indeed positively related to restrained eating. RS was positively related to perceived dieting success, yet, EC did not moderate this association.

CONCLUSION

The current study adds to the evidence that PS is related to individuals' motivation to restrict their food intake. Furthermore, it shows support for the suggestion that RS may facilitate food restriction.

Randomized controlled trials of self-monitoring interventions with or without incentives for diet and exercise among individuals with overweight or obesity: Psychological and behavioural effects

OBJECTIVES

To test the effects of three behavioural interventions (daily monetary incentives + self-monitoring, delayed lump sum monetary incentives + self-monitoring, and self-monitoring only) on psychological constructs and fruit and vegetable consumption or physical activity behaviour change among a sample of adults with overweight or obesity.

DESIGN

A pair of 3-arm longitudinal randomized controlled trials compared daily monetary incentives + self-monitoring, delayed lump sum monetary incentives + self-monitoring, and self-monitoring only interventions for either fruit and vegetable consumption or physical activity.

METHODS

Individuals reporting elevated weight status and insufficient engagement in one of the target behaviours were randomly assigned to one of three 3-week interventions. All three interventions involved daily self-monitoring of the behaviour, and two provided monetary incentives contingent upon reported behaviour. Participants completed measures of psychological constructs and reported behaviour at baseline, the end of the intervention, and two and four weeks post-intervention.

RESULTS

Participants across all three intervention conditions demonstrated increased engagement in the target behaviour from pre- to post-intervention and reported behaviour remained above baseline levels at both follow-up time points. Increases in reported behaviour during the intervention were associated with increases in self-efficacy, and this enhanced self-efficacy prospectively predicted sustained reported behaviour at follow-up. However, contrary to hypotheses, the incentive interventions including self-monitoring were not more efficacious than self-monitoring alone, and increased reported behaviour was not associated with enhancements in attitudes.

CONCLUSIONS

Self-monitoring interventions can aid behaviour change efforts, and behavioural practice during these interventions can increase self-efficacy. However, among adults with overweight or obesity who are seeking behaviour change interventions, incentive-based self-monitoring approaches may not be superior to self-monitoring alone in driving behaviour change and maintenance.

The role of reward sensitivity in obesity and its association with Transcription Factor AP-2B: A longitudinal birth cohort study

OBJECTIVE

One factor potentially contributing to obesity is reward sensitivity. We investigated the association between reward sensitivity and measures of obesity from 9-33 years of age, paying attention to the inner structure of reward sensitivity.

METHODS

The sample included both birth cohorts (originally n = 1176) of the Estonian Children Personality Behaviour and Health Study. The association between reward sensitivity and measures of obesity was assessed using mixed-effects regression models. Associations at ages 9 (younger cohort only), 15, 18, 25 and 33 (older cohort) years were analyzed by one-way ANOVA. The indirect effect of the gene encoding transcription factor 2 beta (TFAP2B) on obesity through reward sensitivity was tested using mediation analysis.

RESULTS

According to linear mixed effects regression models, an increase in scores of Insatiability by Reward and both of its components, Excessive Spending and Giving in to Cravings, significantly increased body weight, body mass index, sum of five skinfolds, waist circumference, hip circumference and waist-to-height ratio from 15 to 25 years of age. Findings were similar at age 9 and 33 years. In contrast, no association between obesity and Openness to Rewards or its facets was observed. The TFAP2B genotype was also associated with fixation to rewards in females, but not with striving towards reward multiplicity.

CONCLUSION

Our results suggest that reward sensitivity is associated with obesity by its reward fixation component. The heterogeneity of the reward sensitivity construct should be taken into account in studies on body composition.

Using confidence interval-based estimation of relevance to explore bottom-up and top-down determinants of problematic eating behavior in children and adolescents with obesity from a dual pathway perspective

Prevalence of overweight and obesity in children and adolescents is high, not only in Western countries but also in developing countries. Efforts to improve prevention and treatment programs are needed. Given their essential role in weight problems, knowledge of determinants of problematic eating behavior ('External Eating' and 'Emotional Eating') is crucial for intervention development. Inspired by Appelhans' Dual Process Theory of Eating Behavior, the present study evaluated the importance of top-down regulative capacities and bottom-up reactivity, using the CIBER approach. CIBER is an innovative statistical approach to test the importance of behavior determinants, based on confidence intervals, instead of significance testing of point estimates. Survey data on different aspects of executive functioning (as indices of regulative capacities: Inhibition, Cognitive Flexibility, Emotional Control, Initiation, Working Memory, Planning/Organizing, Organization of materials, and Monitoring) and reward sensitivity (as an index of reactivity) were collected in a large sample of children and adolescents (n = 572) with severe obesity (adjBMI > 180%). Results showed that Emotional Eating is determined by Emotional Control, while External Eating is determined by Reward Sensitivity. The finding that differential mechanisms underlie different aspects of problematic eating suggests the need for using tailored intervention techniques to address altered reactivity and weak regulative capacities.

The impact of short sleep on food reward processes in adolescents

Short sleep has been linked to adolescent risk of obesity, but questions remain regarding the dietary mechanisms by which this occurs. We tested whether mildly shortening sleep influences how rewarding and appealing healthy adolescents find several kinds of foods. Eighty-eight healthy adolescents completed a within-subjects crossover sleep experiment comparing 5 days of Short Sleep (6.5 hr sleep opportunity) with 5 days of Healthy Sleep (9.5 hr sleep opportunity). Following each condition, adolescents completed measures of food appeal and reinforcing value of food across five food types: sweets/desserts, fruits/vegetables, lean meats/eggs, fast food and processed snacks. Adolescents averaged 2.2 hr/night longer sleep periods in Healthy Sleep versus Short Sleep. We observed a significant interaction of experimental order with sleep condition on three of four primary outcomes related to the appeal and reinforcing value of foods (p's < .005). When Short Sleep preceded Healthy Sleep, adolescents endorsed significantly greater appeal (p < .04) and rewarding value of food (p's ranging from <.01 to .048) during Short Sleep (compared to Healthy Sleep). However, when Healthy Sleep preceded Short Sleep, we did not observe a main effect of sleep condition on the same outcomes (p's > .05). This study provides evidence that restricting adolescents' sleep opportunity to 6.5 hr (compared to sleeping a healthy amount) increases the appeal and reinforcing value of a variety of foods, but this may occur only under protracted short sleep. Increased food reward may be one mechanism linking chronically shortened sleep with risk of obesity in adolescence.

Can Parenting Practices Moderate the Relationship between Reward Sensitivity and Adolescents' Consumption of Snacks and Sugar-Sweetened Beverages?

Background: Reward sensitivity has been associated with adolescents’ intake of unhealthy snacks and sugar-sweetened beverages. However, so far, there are no studies published describing the impact of parenting practices on this relationship. The present study will, therefore, investigate whether food parenting practices can moderate the association between reward sensitivity and diet intakes. Method: A cross-sectional research study was conducted among 14- to 16-year old Flemish adolescents (n = 867, age 14.7 ± 0.8 y, 48.1% boys) and a subset of their parents (n = 131), collecting data on daily intakes, reward sensitivity, and food parenting practices. Linear regression was used to assess the moderation effect of parenting practices (both adolescent- and parent-reported) on the relationship between reward sensitivity, and diet using SPSS 25.0. Results: In the main analysis (adolescent-reported), no significant moderation effects were found for parenting practices on the relationship between reward sensitivity and diet. However, the sensitivity analysis (parent-reported) showed a moderation effect for health-reducing parenting practices on the association between reward sensitivity and unhealthy snack intake (β = 0.297, 95% CI = 0.062, 0.531, p = 0.01). Conclusion: Given the difference in the effect of parenting practices between the adolescent- and parent-reported data, our inconclusive findings warrant more research in larger adolescent-parent dyad samples.

Striatal dopamine transporter changes after glucose loading in humans

AIMS

The dopamine transporter (DAT) actively translocates dopamine that is released from the presynaptic neurons across the membranes of nerve terminals into the extracellular space. We hypothesized that glucose loading-induced changes in striatal DAT levels could be associated with food intake in humans.

MATERIALS AND METHODS

An intravenous bolus injection of ¹⁸ F-FP-CIT was administered after infusion of glucose or placebo (normal saline), and emission data were acquired over 90 minutes in 33 healthy males. For a volume-of-interest-based analysis, an atlas involving sub-striatal regions of ventral striatum (VST), caudate nucleus and putamen was applied. DAT availability and binding potential (BP_ND ) were measured using a simplified reference tissue method with cerebellum as the reference.

RESULTS

The glucose-loaded BP_ND from the VST negatively correlated with body mass index (BMI), whereas the placebo-loaded BP_ND from the VST did not. After loading with glucose, there were substantial increases in BP_ND s: 18.3%, 71.7% and 34.0% on average in the VST, caudate nucleus and putamen, respectively.

CONCLUSION

Striatal DAT changes after glucose loading, and BMI is associated with glucose-loaded DAT availability, not with placebo-loaded DAT availability. DAT might have a role in the reward system of eating behavior.

No Differential Reward Responsivity and Drive, Punishment Sensitivity or Attention for Cues Signaling Reward or Punishment in Adolescents With Obesity

Although it has been proposed that obese and healthy weight individuals might differ in their reward and punishment sensitivity, the literature shows diverse and inconsistent findings. The current study was set out to examine the role of reward and punishment sensitivity in adolescent obesity by differentiating between reward responsivity and reward drive, and by complementing self-report measures with performance-based measures indexing attention for cues signaling reward and punishment as well as effort to approach reward and avoid punishment. Participants were adolescents aged 12-23, with obesity (n = 51, adjusted BMI [(actual BMI/Percentile 50 of BMI for age and gender) × 100) between 143 and 313%], and with a healthy weight (n = 51, adjusted BMI between 75 and 129%). Individuals with obesity did not significantly differ from adolescents with a healthy weight in reward responsivity, reward drive or attention to cues signaling reward. Further, no differences in self-reported punishment sensitivity or attention for cues signaling punishment were found between obese and healthy weight adolescents. The current study thus does not corroborate the theories that general reward and punishment sensitivity play a role in obesity.

A dual-process psychobiological model of temperament predicts liking and wanting for food and trait disinhibition

A dual-process model of temperament, incorporating the Behavioural Inhibition System (BIS), Behavioural Activation System (BAS) and effortful control (EC), may help to predict hedonic responses to palatable food and trait disinhibition.

PURPOSE

This study aimed to determine if the BIS, BAS and EC predicted liking and wanting for high-fat, sweet foods in adults with overweight and obesity, and if collectively, these variables predicted the eating behaviour trait of Disinhibition.

METHODS

168 adults (104 females, mean BMI = 33.3 kg/m²) completed the Three Factor Eating Questionnaire, the Carver and White BIS/BAS scales, the Adult Temperament Questionnaire-Effortful Control Scale - Short Form and the Leeds Food Preference Questionnaire. The strength of the BIS, BAS and EC in predicting wanting and liking for high-fat sweet foods, and trait Disinhibition was assessed using hierarchical multiple regression.

RESULTS

Both the BIS and EC predicted liking, F (6, 161) = 5.05, p < .001, R² = 0.16, and EC inversely predicted wanting, F (6, 161) = 3.28, p = .005, R² = 0.11. The BIS, EC and liking predicted, F (8, 159) = 11.0, p < .001, R² = 0.36, and explained 36% of Disinhibition. The BAS did not predict wanting, liking or Disinhibition.

CONCLUSIONS

These results demonstrate that a sensitive BIS and a lower level of effortful control predicts food reward and Disinhibition in overweight and obese adults. Consequently, interventions that aim to increase effortful control and reduce BIS reactivity may be beneficial for reducing hedonically motivated, disinhibited eating behaviour.

Perceived stress correlates with visceral obesity and lipid parameters of the metabolic syndrome: A systematic review and meta-analysis

BACKGROUND

Perceived stress has been proposed as a risk factor of metabolic syndrome. However, correlations between perceived stress and parameters of the metabolic syndrome have not been properly analyzed despite extensive research data on the topic. Our current meta-analysis aimed to examine the mutual association between perceived stress of patients and parameters of metabolic syndrome.

METHODS

This systematic review has been registered on the PROSPERO database (registration number CRD42017055293). Eligible studies divided participants based on their stress level or on the presence of metabolic syndrome. They reported at least one parameter of the metabolic syndrome or the stress level of the participants measured with some stress scale. Data from 17 articles met the eligibility criteria and were included. Random effects model with the DerSimonian and Laird weighting methods was applied. I-squared indicator and Q test were performed to assess heterogeneity.

RESULTS

Although the majority of individual studies failed to demonstrate correlations between stress and their analyzed parameters of metabolic syndrome, our meta-analysis showed a significant association between stress and BMI [average effect size (ES) with 95% confidence interval (95%CI), ES = 0.65, 95%CI 0.16, 1.14), waist circumference (ES = 1.84 cm, 95%CI 0.79, 2.89) and serum triglyceride level (ES = 7.52 mg/dl, 95%CI 0.07, 14.96). Additional analysis confirmed effects of stress on serum HDL (ES = - 1.699 mg/dl, 95%CI -2.966, -0.432) and diastolic blood pressure (ES = 1.04 mmHg, 95%CI 0.18, 1.89). No correlations were found for fasting glucose or systolic blood pressure. No association between metabolic syndrome and stress level of patients was detected either.

CONCLUSION

The potentially key role of visceral obesity in the association between perceived stress and dyslipidemia or diastolic blood pressure are discussed together with potential moderators (e.g. gender-differences, variations in stress assessment and metabolic syndrome criteria) that may explain the inconsistent, contradictory results of the individual studies.

Infant temperament and parent use of food to soothe predict change in weight-for-length across infancy: early risk factors for childhood obesity

OBJECTIVES

Greater weight gain in infancy is a risk factor for childhood obesity. The present study examined the interaction between infant temperament and parent use of food to soothe infant distress (FTS) as predictors of weight gain across the first 2 years of life.

SUBJECTS/METHODS

A total of 160 mother-infant dyads were recruited into a longitudinal study. Infant temperament was assessed by parents through a questionnaire (surgency, negativity) and by observer ratings (surgency, irritability) during a laboratory visit when infants were 6 months old. Parents also completed a 3-day infant cry diary when their children were 6 months of age to assess when they used food in response to infant cry/fuss bouts. Infant weight/length was measured in the lab at 6 and 18 months. Multiple regressions were run to test the moderating effect of FTS on weight gain.

RESULTS

Significant interactions were revealed for both measures of surgency and parent FTS in predicting weight gain. Surgent infants whose parents had a greater tendency to use FTS had greater weight-for-length gain in 1 year than if their parents tended to use less FTS. The interaction between observer ratings of irritability and parent FTS was also significant but in an unexpected direction.

CONCLUSIONS

The findings point to the role of temperament, specifically surgency, in weight gain during infancy, but only if their parents used FTS. Surgency may have evoked this feeding practice that increased their health risk.

The Role of Resilience in Internet Addiction among Adolescents between Sexes: A Moderated Mediation Model

The behavioral inhibition/activation systems (BIS/BAS) have been considered to be predictors of Internet addiction, mediated by clinical variables such as anxiety and depression. However, resilience has been suggested as a protective factor toward Internet addiction, and certain sex differences in resilience buffering the effects of vulnerability have been reported. Thus, the aim of this study was to identify any role of resilience that might moderate the effects of BIS/BAS on Internet addiction through multiple clinical variables in boys and girls. A total of 519 middle-school students (268 boys and 251 girls, all 14 years old) were administered a questionnaire battery that measures Internet addiction, BIS/BAS, depression, anxiety, impulsivity, anger, and resilience. We used the PROCESS macro in SPSS to perform moderation and mediation analysis. Findings revealed that although a somewhat similar mediation model was supported in both sexes, moderating effects of resilience only emerged in girls. The results showed a protective role of resilience differing between sexes. These results suggest that clinicians should consider sex in the way resilience works as a protective factor against Internet addiction and focus on mitigating the effects of vulnerability by enhancing resilience in female Internet addicts.

Feasibility and impact study of a reward-based mobile application to improve adolescents' snacking habits

OBJECTIVE

Adolescents' snacking habits are driven by both explicit reflective and implicit hedonic processes. Hedonic pathways and differences in sensitivity to food rewards in addition to reflective determinants should be considered. The present study evaluated the feasibility and impact of a mobile phone-delivered intervention, incorporating explicit reflective and implicit rewarding strategies, on adolescents' snack intake.

DESIGN

Adolescents (n 988; mean age 14·9 (sd 0·70) years, 59·4 % boys) completed a non-randomized clustered controlled trial. Adolescents (n 416) in the intervention schools (n 3) were provided with the intervention application for four weeks, while adolescents (n 572) in the control schools (n 3) followed the regular curriculum. Outcomes were differences in healthy snacking ratio and key determinants (awareness, intention, attitude, self-efficacy, habits and knowledge). Process evaluation data were collected via questionnaires and through log data of the app.

RESULTS

No significant positive intervention effects on the healthy snack ratio (b=-3·52 (se 1·82), P>0·05) or targeted determinants were observed. Only 268 adolescents started using the app, of whom only fifty-five (20·5 %) still logged in after four weeks. Within the group of users, higher exposure to the app was not significantly associated with positive intervention effects. App satisfaction ratings were low in both high and low user groups. Moderation analyses revealed small positive intervention effects on the healthy snack ratio in high compared with low reward-sensitive boys (b=1·38 (se 0·59), P<0·05).

CONCLUSIONS

The intervention was not able to improve adolescents' snack choices, due to low reach and exposure. Future interventions should consider multicomponent interventions, teacher engagement, exhaustive participatory app content development and tailoring.

Longitudinal Associations Between Anhedonia and Body Mass Index Trajectory Groups Among Adolescents

PURPOSE

Although evidence suggests that anhedonia-a reduced ability to experience pleasure in response to rewarding stimuli-may predict weight gain during adolescence, it remains unclear whether changes in anhedonia during adolescence are associated with changes in body mass index (BMI). This study examines longitudinal associations between changes in anhedonia and developmental trajectories of BMI during adolescence.

METHODS

Self-report measures of anhedonia and BMI were collected at five semiannual assessments among students from 10 high schools in Los Angeles, CA, area (N = 3,396) followed up from the 9th grade to the 11th grade. Four BMI trajectories were identified using growth mixture modeling: (1) stable normative weight; (2) overweight to normative weight (i.e., decreasing BMI); (3) overweight to chronically obese (increasing BMI); and (4) normative weight to overweight (increasing BMI). Latent growth curve modeling estimated baseline level and changes in anhedonia. A multinomial logistic regression model tested associations of baseline level and slope of anhedonia with the four BMI trajectory groups.

RESULTS

Compared with the stable normative BMI trajectory group, each 1-unit standard deviation increase in anhedonia slope increased the odds of membership in the overweight to chronically obese group (odds ratio [OR] [95% confidence interval {CI}] = 1.29 [1.09-1.49], p < .001) and in the normative weight to overweight group (OR [95% CI] = 1.28 [1.04-1.53], p = .006), and decreased the odds of membership in the overweight to normative weight group (OR [95% CI] = .78 [.57-.95], p = .01).

CONCLUSIONS

Across a 2-year period of high school, the rate of change in anhedonia is associated with certain BMI trajectories linked with poorer metabolic health. Increasing anhedonia may be an important risk factor to consider in adolescent obesity prevention.

Executive and Reward-Related Function in Pediatric Obesity: A Meta-Analysis

OBJECTIVE

This study examined the effect of pediatric obesity on executive function and reward-related decision-making, cognitive processes that are relevant to obesogenic behaviors, and evaluated their association with sample (e.g., age, gender, intelligence, and socioeconomic status, SES) and study/task (e.g., categorical/continuous variable, food stimuli) characteristics.

METHODS

A random-effects meta-analysis was conducted using Hedge's g effect sizes of published studies from 1960 to 2016, limited to children younger than the age of 21 years without medical comorbidities. Analysis included estimation of heterogeneity (τ²), publication bias (funnel-plot symmetry and fail-safe N), and sensitivity analyses for sample and study/task characteristics.

RESULTS

Across 68 studies with 70 samples, obesity was associated with worse functioning overall (-0.24; 95CI: -0.30 to -0.19; p < 0.001) and for each component process (attention, switching, inhibition, interference, working memory, reward, delay of gratification: -0.19 to -0.38; p's < 0.017), except trait impulsivity (-0.06; 95CI: -0.18 to 0.07). Deficits increased with age and female composition of the sample for inhibition (p = 0.002). No other characteristics moderated effect of obesity.

CONCLUSIONS

Small-to-moderate negative associations with obesity were observed for executive and reward-related performance, but not on reported impulsivity in studies with children younger than the age of 21 years. These results were not moderated by IQ, SES, and study/task characteristics. Age and gender moderated association with inhibition, with a larger obesity-related deficit in older and predominantly female samples. These results suggest cognitive and demographic intervention targets for prevention and mitigation of obesogenic behavior.

Lower dopamine tone in the striatum is associated with higher body mass index

Existing literature suggests that striatal dopamine (DA) tone may be altered in individuals with higher body mass index (BMI), but evidence accrued so far only offers an incomplete view of their relationship. Here, we characterized striatal DA tone using more comprehensive measures within a larger sample than previously reported. In addition, we explored if there was a relationship between striatal DA tone and disinhibited eating. 60 healthy participants underwent a 6-[¹⁸F]fluoro-L-3,4-dihydroxyphenylalanine (¹⁸F-DOPA) positron emission tomography (PET) scan. Disinhibited eating was measured with the Three-Factor Eating Questionnaire on a baseline visit. Individual whole-brain PET parameter estimates, namely ¹⁸F-DOPA influx rate constant (k_occ i.e. DA synthesis capacity), ¹⁸F-DA washout rate (k_loss) and effective distribution volume ratio (EDVR= k_occ/ k_loss), were derived with a reversible-tracer graphical analysis approach. We then computed parameter estimates for three regions-of-interests (ROIs), namely the ventral striatum, putamen and caudate. Overweight/mildly obese individuals had lowered EDVR than normal weight individuals in all three ROIs. The most prominent of these associations, driven by lowered k_occ (r = -.28, p = .035) and heightened k_loss (r = .48, p < .001), was found in the ventral striatum (r = -.46, p < .001). Disinhibition was greater in higher-BMI individuals (r = .31, p = .015), but was unrelated to PET measures and did not explain the relationship between PET measures and BMI. In sum, our findings resonate with the notion that overweight/mildly obese individuals have lower striatal DA tone and suggest new avenues for investigating their underlying mechanisms.

Parent-Reported BIS/BAS Scales for Children: Factor Structure and Measurement Invariance Across Age and Gender

The present study examined the factor structure and measurement invariance of the Behavioral Inhibition System/Behavioral Approach System (BIS/BAS) scales parent-report in children and adolescents ( N = 1,444, 58% girls) across age (Group 1, 2-5 years; Group 2, 6-9 years; Group 3, 10-13 years; Group 4, 14-18 years old) and gender. The results consistently underscored a four-factor structure, resembling the original factor structure, with one BIS-factor and three BAS-factors. Multigroup confirmatory factor analysis showed full measurement invariance across gender as well as across Group 1 and 2, and Group 2 and 3. Strong measurement invariance was found across Group 3 and 4, Group 1 and 3, and Group 2 and 4. Configural and metric invariance was found across Group 1 and 4. Hence, mean-level BIS/BAS scores can be compared across gender and age although comparison between preschool children (Group 1) and late secondary school children (Group 4) should be done with caution.

BIS/BAS Scale in Primary School Children: Parent-Child Agreement and Longitudinal Stability

The current study provided psychometric information on the parent and child version of the Behavioural Inhibition System (BIS)/Behavioural Approach System (BAS) scale. Parent-child agreement was evaluated (N = 217, 7.5 to 14 years, 50% boys). Moreover, absolute and rank order stability of mother-reported BIS/BAS scores over a 2-year period were assessed (N = 207, 5.5 to 11 years at baseline, 49% boys). Only full measurement invariant (sub-)scales were considered in the parent-child agreement and longitudinal stability assessment. Parent and child ratings were found to be measurement invariant but discrepant on BAS Drive and BAS Reward Responsiveness. In younger children, child ratings on BAS Drive tended to be higher than parent ratings, whereas in older children, child ratings tended to be lower than parent ratings. Further, the discrepancy between the BAS Drive ratings of fathers and children was higher than the discrepancy between the BAS Drive ratings of mothers and children. Finally, the study results suggested 2-year absolute and rank order stability of the measurement-invariant, mother-reported BIS and BAS Drive scores in children aged 5.5 to 11 years at baseline.

Overlapping Neural Endophenotypes in Addiction and Obesity

Impulsivity refers to a tendency to act rapidly without full consideration of consequences. The trait is thought to result from the interaction between high arousal responses to potential rewards and poor self-control. Studies have suggested that impulsivity confers vulnerability to both addiction and obesity. However, results in this area are unclear, perhaps due to the high phenotypic complexity of addictions and obesity. Focusing on impulsivity, the aim of this review is to tackle the putative overlaps between addiction and obesity in four domains: (1) personality research, (2) neurocognitive tasks, (3) brain imaging, and (4) clinical evidence. We suggest that three impulsivity-related domains are particularly relevant for our understanding of similarities between addiction and obesity: lower self-control (high Disinhibition/low Conscientiousness), reward sensitivity (high Extraversion/Positive Emotionality), and negative affect (high Neuroticism/Negative Emotionality). Neurocognitive studies have shown that obesity and addiction are both associated with increased impulsive decision-making and attention bias in response to drug or food cues, respectively. Mirroring this, obesity and different forms of addiction seem to exhibit similar alterations in functional MRI brain activity in response to reward processing and during self-control tasks. Overall, our review provides an integrative approach to understand those facets of obesity that present similarities to addictive behaviors. In addition, we suggest that therapeutic interventions targeting inhibitory control may represent a promising approach for the prevention and/or treatment of obesity.

Adding a reward increases the reinforcing value of fruit

Adolescents' snack choices could be altered by increasing the reinforcing value (RV) of healthy snacks compared with unhealthy snacks. This study assessed whether the RV of fruit increased by linking it to a reward and if this increased RV was comparable with the RV of unhealthy snacks alone. Moderation effects of sex, hunger, BMI z-scores and sensitivity to reward were also explored. The RV of snacks was assessed in a sample of 165 adolescents (15·1 (sd 1·5) years, 39·4 % boys and 17·4 % overweight) using a computerised food reinforcement task. Adolescents obtained points for snacks through mouse clicks (responses) following progressive ratio schedules of increasing response requirements. Participants were (computer) randomised to three experimental groups (1:1:1): fruit (n 53), fruit+reward (n 60) or unhealthy snacks (n 69). The RV was evaluated as total number of responses and breakpoint (schedule of terminating food reinforcement task). Multilevel regression analyses (total number of responses) and Cox's proportional hazard regression models (breakpoint) were used. The total number of responses made were not different between fruit+reward and fruit (b -473; 95 % CI -1152, 205, P=0·17) or unhealthy snacks (b410; 95 % CI -222, 1043, P=0·20). The breakpoint was slightly higher for fruit than fruit+reward (HR 1·34; 95 % CI 1·00, 1·79, P=0·050), whereas no difference between unhealthy snacks and fruit+reward (HR 0·86; 95 % CI 0·62, 1·18, P=0·34) was observed. No indication of moderation was found. Offering rewards slightly increases the RV of fruit and may be a promising strategy to increase healthy food choices. Future studies should however, explore if other rewards, could reach larger effect sizes.

[Eating behavior in pediatric obesity: Of the advantages of combining the neurobiological and neuropsychological approaches]

Obesity is currently considered a major public health concern, as shown by the growing number of people with excess weight, alarmingly in infants, and despite medical care. Many studies have underlined the reasons for medical care failure caused by an inability to sustain a resistant behavior towards palatable food (high sugar and fat content). Hence, previous research has highlighted connections between excessive eating behavior and the activity of neurotransmitters in brain areas involved in affective behavior and the reward circuit. Reduction of the dopaminergic activity in the prefrontal orbital and limbic cortex may raise the question of executive skills, which play a major role in social adaptation and behavior control. These findings remind us of the need to grasp environmental and behavioral factors to better identify cognitive and affective profiles and improve childhood obesity treatment.

Reward sensitivity and body weight: the intervening role of food responsive behavior and external eating

BACKGROUND

During the last three decades, the prevalence of childhood overweight and obesity has increased worldwide. It is well established that different child-related factors such as food approach behaviors (i.e. eating behaviors that imply movements towards food) contribute to the development of overweight. However, research is lacking on the underlying mechanisms leading to food approach behaviors, which in turn lead to overweight.

SUBJECT/METHODS

Via parent-report questionnaires, we investigated the relation between the personality trait reward sensitivity and body weight in a convenience sample of 211 children aged 2.5-9 years. We further investigated the intervening role of food approach behaviors in the association between reward sensitivity and body weight.

RESULTS

Unexpectedly, there was no direct association between reward sensitivity and body weight. Despite the absence of a direct effect, a significant indirect association was found between reward sensitivity and body weight through the intervening food approach variables (i.e. food responsive behavior and external eating).

CONCLUSIONS

These results highlight the importance of the focus on eating behaviors as well as trait characteristics in prevention programs for overweight.

Fat and lean tissue accretion in relation to reward motivation in children

'Reward sensitivity' explains inter-individual differences in the motivation to obtain rewards when reward cues are perceived. This psychobiological trait has been linked to higher consumption of palatable food when exposed to palatable food cues. The current study aims to examine if reward sensitivity explains differences in patterns of fat and lean tissue accretion over time in children. A longitudinal observational study with measurement waves in 2011 (baseline), 2012, 2013, and 2015 was conducted. The sample was a population-based Flemish cohort of children (n = 446, 50% boys and 5.5-12 years at baseline; 38.8% of the baseline sample also participated in 2015). Baseline reward sensitivity of the children was assessed by parent ratings on the Drive subscale of the Behavioral Inhibition System/Behavioral Approach System scales. Age- and sex-independent Fat and Lean Mass Index z-scores (zFMI and zLMI respectively) were computed for each study wave based on air-displacement plethysmography. In girls, but not boys, reward sensitivity was positively associated with the baseline zFMI and zLMI (95% confidence intervals of unstandardized estimates: 0.01 to 0.11 and 0.01 to 0.10 respectively, P values 0.01 and 0.02 respectively). Further, reward sensitivity explained 14.8% and 11.6% of the change in girls' zFMI and zLMI respectively over four years: the zFMI and zLMI increased and decreased respectively in high reward sensitive girls (95% confidence intervals of unstandardized estimates: 0.01 to 0.11 and -0.12 to -0.01 respectively, P values 0.01 and 0.02 respectively). Hence, girls high in reward sensitivity had significantly higher adiposity gain over four years parallel with lower increase in lean mass than was expected on the basis of their age and height. These results may help to identify appropriate targets for interventions for obesity prevention.

Using a gamified monitoring app to change adolescents' snack intake: the development of the REWARD app and evaluation design

BACKGROUND

As the snacking pattern of European adolescents is of great concern, effective interventions are necessary. Till now health promotion efforts in children and adolescents have had only limited success in changing adolescents' eating patterns and anthropometrics. Therefore, the present study proposes an innovative approach to influence dietary behaviors in youth based on new insights on effective behavior change strategies and attractive intervention channels to engage adolescents. This article describes the rationale, the development, and evaluation design of the 'Snack Track School' app. The aim of the app is to improve the snacking patterns of Flemish 14- to 16-year olds.

METHODS

The development of the app was informed by the systematic, stepwise, iterative, and collaborative principles of the Intervention Mapping protocol. A four week mHealth intervention was developed based on the dual-system model with behavioral change strategies targeting both the reflective (i.e., active learning, advance organizers, mere exposure, goal-setting, monitoring, and feedback) and automatic processes (i.e., rewards and positive reinforcement). This intervention will be evaluated via a controlled pre-post design in Flemish schools among 1400 adolescents.

DISCUSSION

When this intervention including strategies focused on both the reflective and automatic pathway proves to be effective, it will offer a new scientifically-based vision, guidelines and practical tools for public health and health promotion (i.e., incorporation of learning theories in intervention programs).

TRIAL REGISTRATION

NCT02622165 registrated November 15, 2015 on clinicaltrials.gov.

Attentional Bias for Reward and Punishment in Overweight and Obesity: The TRAILS Study

More than 80% of obese adolescents will become obese adults, and it is therefore important to enhance insight into characteristics that underlie the development and maintenance of overweight and obesity at a young age. The current study is the first to focus on attentional biases towards rewarding and punishing cues as potentially important factors. Participants were young adolescents (N = 607) who were followed from the age of 13 until the age of 19, and completed a motivational game indexing the attentional bias to general cues of reward and punishment. Additionally, self-reported reward and punishment sensitivity was measured. This study showed that attentional biases to cues that signal reward or punishment and self-reported reward and punishment sensitivity were not related to body mass index or the change in body mass index over six years in adolescents. Thus, attentional bias to cues of reward and cues of punishment, and self-reported reward and punishment sensitivity, do not seem to be crucial factors in the development and maintenance of overweight and obesity in adolescents. Exploratory analyses of the current study suggest that the amount of effort to gain reward and to avoid punishment may play a role in the development and maintenance of overweight and obesity. However, since the effort measure was a construct based on face validity and has not been properly validated, more studies are necessary before firm conclusions can be drawn.

Food Approach and Food Avoidance in Young Children: Relation with Reward Sensitivity and Punishment Sensitivity

It has recently been suggested that individual differences in Reward Sensitivity and Punishment Sensitivity may determine how children respond to food. These temperamental traits reflect activity in two basic brain systems that respond to rewarding and punishing stimuli, respectively, with approach and avoidance. Via parent-report questionnaires, we investigate the associations of the general motivational temperamental traits Reward Sensitivity and Punishment Sensitivity with Food Approach and Food Avoidance in 98 preschool children. Consistent with the conceptualization of Reward Sensitivity in terms of approach behavior and Punishment Sensitivity in terms of avoidance behavior, Reward Sensitivity was positively related to Food Approach, while Punishment Sensitivity was positively related to Food Avoidance. Future research should integrate these perspectives (i.e., general temperamental traits Reward Sensitivity and Punishment Sensitivity, and Food Approach and Avoidance) to get a better understanding of eating behavior and related body weight.

Associations between dopamine D2 receptor availability and BMI depend on age

OBJECTIVE

The dopamine D2/3 receptor subtypes (DRD2/3) are the most widely studied neurotransmitter biomarker in research on obesity, but results to date have been inconsistent, have typically involved small samples, and have rarely accounted for subjects' ages despite the large impact of age on DRD2/3 levels. We aimed to clarify the relation between DRD2/3 availability and BMI by examining this association in a large sample of subjects with BMI spanning the continuum from underweight to extremely obese.

SUBJECTS

130 healthy subjects between 18 and 81years old underwent PET with [18F]fallypride, a high affinity DRD2/3 ligand.

RESULTS

As expected, DRD2/3 availability declined with age. Critically, age significantly interacted with DRD2/3 availability in predicting BMI in the midbrain and striatal regions (caudate, putamen, and ventral striatum). Among subjects under 30years old, BMI was not associated with DRD2/3 availability. By contrast, among subjects over 30years old, BMI was positively associated with DRD2/3 availability in the midbrain, putamen, and ventral striatum.

CONCLUSION

The present results are incompatible with the prominent dopaminergic hypofunction hypothesis that proposes that a reduction in DRD2/3 availability is associated with increased BMI, and highlights the importance of age in assessing correlates of DRD2/3 function.

Strategies to improve the Willingness to Taste: The moderating role of children's Reward Sensitivity

The present study investigates the effectiveness of different strategies to improve Willingness to Taste disliked vegetables and the moderating role of Reward Sensitivity. Preschool children (N = 204; age: M = 4.48, SD = 1.01) were randomly allocated to one of four different Willingness to Taste strategies. The findings indicate that first, Willingness to Taste is higher in the modelling and reward strategies compared to neutral instructions. Second, there is a differential effect of Willingness to Taste strategies dependent upon individual differences: children high in Reward Sensitivity were more likely to taste immediately when rewarded, while children low in Reward Sensitivity were more willing to taste when verbally encouraged, but with hesitation. This article thus highlights the roles of both individual differences and behavioral techniques for promoting a healthy diet in children.

Removal of high-fat diet after chronic exposure drives binge behavior and dopaminergic dysregulation in female mice

A significant contributor to the obesity epidemic is the overconsumption of highly palatable, energy dense foods. Chronic intake of palatable foods is associated with neuroadaptations within the mesocorticolimbic dopamine system adaptations which may lead to behavioral changes, such as overconsumption or bingeing. We examined behavioral and molecular outcomes in mice that were given chronic exposure to a high-fat diet (HFD; 12weeks), with the onset of the diet either in adolescence or adulthood. To examine whether observed effects could be reversed upon removal of the HFD, animals were also studied 4weeks after a return to chow feeding. Most notably, female mice, particularly those exposed to HFD starting in adolescence, demonstrated the emergence of binge-like behavior when given restricted access to a palatable food. Further, changes in dopamine-related gene expression and dopamine content in the prefrontal cortex were observed. Some of these HFD-driven phenotypes reversed upon removal of the diet, whereas others were initiated by removal of the diet. These findings have implications for obesity management and interventions, as both pharmacological and behavioral therapies are often combined with dietary interventions (e.g., reduction in calorie dense foods).

Sensitivity to reward and adolescents' unhealthy snacking and drinking behavior: the role of hedonic eating styles and availability

Background

Although previous research found a positive association between sensitivity to reward (SR) and adolescents’ unhealthy snacking and drinking behavior, mechanisms explaining these associations remain to be explored. The present study will therefore examine whether the associations between SR and unhealthy snack and/or sugar-sweetened beverage (SSB) intake are mediated by external and/or emotional eating and if this mediation is moderated by availability at home or at school.

Methods

Cross-sectional data on snacking, availability of snacks at home and at school, SR (BAS drive scale) and external and emotional eating (Dutch eating behavior questionnaire) of Flemish adolescents (n = 1104, mean age = 14.7 ± 0.8 years; 51 % boys; 18.0 % overweight) in 20 schools spread across Flanders were collected. Moderated mediation analyses were conducted using generalized structural equation modeling in three steps: (1) direct association between SR and unhealthy snack or SSB intake, (2) mediation of either external or emotional eating and (3) interaction of home or school availability and emotional or external eating.

Results

Partial mediation of external eating (a*b = 0.69, p < 0.05) and of emotional eating (a*b = 0.92, p < 0.01) in the relation between SR and intake of unhealthy snacks was found (step 2). The relation between SR and SSB intake was not mediated by external or emotional eating (step 2). No moderation effects of home or school availability were found (step 3).

Conclusion

Our findings indicate that the association between SR and the consumption of unhealthy snacks is partially explained by external and emotional eating in a population-based sample of adolescents irrespective of the home or school availability of these foods.

Neural Processing of Calories in Brain Reward Areas Can be Modulated by Reward Sensitivity

A food's reward value is dependent on its caloric content. Furthermore, a food's acute reward value also depends on hunger state. The drive to obtain rewards (reward sensitivity), however, differs between individuals. Here, we assessed the association between brain responses to calories in the mouth and trait reward sensitivity in different hunger states. Firstly, we assessed this in data from a functional neuroimaging study (van Rijn et al., 2015), in which participants (n = 30) tasted simple solutions of a non-caloric sweetener with or without a non-sweet carbohydrate (maltodextrin) during hunger and satiety. Secondly, we expanded these analyses to regular drinks by assessing the same relationship in data from a study in which soft drinks sweetened with either sucrose or a non-caloric sweetener were administered during hunger (n = 18) (Griffioen-Roose et al., 2013). First, taste activation by the non-caloric solution/soft drink was subtracted from that by the caloric solution/soft drink to eliminate sweetness effects and retain activation induced by calories. Subsequently, this difference in taste activation was correlated with reward sensitivity as measured with the BAS drive subscale of the Behavioral Activation System (BAS) questionnaire. When participants were hungry and tasted calories from the simple solution, brain activation in the right ventral striatum (caudate), right amygdala and anterior cingulate cortex (bilaterally) correlated negatively with BAS drive scores. In contrast, when participants were satiated, taste responses correlated positively with BAS drive scores in the left caudate. These results were not replicated for soft drinks. Thus, neural responses to oral calories from maltodextrin were modulated by reward sensitivity in reward-related brain areas. This was not the case for sucrose. This may be due to the direct detection of maltodextrin, but not sucrose in the oral cavity. Also, in a familiar beverage, detection of calories per se may be overruled by a conditioned response to its flavor. In conclusion, the brain reward response to calories from a long chain starch sugar (maltodextrin) varies with trait reward sensitivity. The absence of this effect in a familiar beverage warrants further research into its relevance for real life ingestive behavior.