Measurement of food reinforcement in preschool children. Associations with food intake, BMI, and reward sensitivity

An acute social stressor decreases reinforcing value of both high and low energy-dense food in college students in a randomized controlled trial

It is well known that a large portion of the population elevates their intake of high energy-dense foods during times of stress; however, it is understudied whether stress affects the reinforcing value of a food reward. Further knowledge of this relationship may help us better understand the positive correlation between reinforcing value of food and obesity. Therefore, it was tested if an acute stressor would increase the reinforcing value of low or high energy-dense food. Participants (N = 70) were randomized to a stress or no-stress condition after which they were allowed to work to gain access to a food reward and reading time. To determine if high energy-dense food was specifically affected, half the participants from each stress manipulation were randomly assigned to work for either grapes or chocolate candies. Participants in the stress condition worked less for food access than those in the no-stress condition, for both low and high energy-dense foods, but stress did not affect the reinforcing value of reading time. These results indicate that, contrary to our hypothesis, in a sample of college students, an acute stressor decreased reinforcing value of food, with no difference between a low and high energy-dense food item.

Do children imitate even when it is costly? New insights from a novel task

Children have a proclivity to learn through faithful imitation, but the extent to which this applies under significant cost remains unclear. To address this, we investigated whether 4- to 6-year-old children (N = 97) would stop imitating to forego a desirable food reward. We presented participants with a task involving arranging marshmallows and craft sticks, with the goal being either to collect marshmallows or build a tower. Children replicated the demonstrated actions with high fidelity regardless of the goal, but retrieved rewards differently. Children either copied the specific actions needed to build a tower, prioritizing tower completion over reward; or adopted a novel convention of stacking materials before collecting marshmallows, and developed their own method to achieve better outcomes. These results suggest children's social learning decisions are flexible and context-dependent, yet that when framed by an ostensive goal, children imitated in adherence to the goal despite incurring significant material costs.

Sex-specific impulsivity, but not other facets of executive function, predicts fat and sugar intake two-years later amongst adolescents with a healthy weight: Findings from the ABCD study

During adolescence, processes that control food intake (executive functions [EF]) undergo extensive refinement; underlying differences in EF may explain the inability to resist overeating unhealthy foods. Yet, overeating fat and sugar also causes changes to EF and cognition but disentangling these relationships has been difficult, as previous studies included youth with obesity. Here, amongst youth initially of a healthy weight, we evaluate whether 1) sex-specific underlying variation in EF/cognition at 9/10-years-old predict fat/sugar two-years later (Y2) and 2) if these relationships are moderated by body mass index (BMI), using linear mixed effects models (controlled for puberty, caregiver education; random effect: study site). Data were leveraged from Adolescent Brain Cognitive Development Study (n = 2987; 50.4% male; 15.4% Latino/a/x; 100% healthy weight at baseline; 12.4% overweight/obese by Y2, data release 4.0). EF and cognition (e.g., inhibition, cognition, motor, memory, impulsivity) were assessed with the NIH toolbox, Rey Auditory Verbal Learning Task, Little Man Task, the BIS/BAS, and UPPS-P. A saturated fat/added sugar (kcals) composite score was extracted from the validated Kids Food Block Screener. For males, greater baseline impulsivity (e.g., Positive Urgency, Lack of Planning and Perseverance) and reward (e.g., Fun seeking, Drive) was related to greater Y2 intake. For both sexes, greater baseline Negative Urgency and higher BMI was related to greater Y2 intake. No other relationships were observed. Our findings highlight a phenotype that may be more at risk for weight gain due to overconsumption of fat/sugar. Thus, prevention efforts may wish to focus on impulsive tendencies for these foods.

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.

Insulin Resistance and Glycated Hemoglobin in Obesity Are Associated With Preference for Sugar-Sweetened Yogurt: A Pilot Study

OBJECTIVE

Insulin resistance is associated with elevated activation of food reward, which should be associated with an increased reinforcing value of food. Research has also shown that sugar is a macronutrient strongly associated with reward and reinforcing value of food. This research is designed to assess whether insulin resistance is associated with a stronger preference for sugar-sweetened, thus elevating blood glucose responses in obese people with varying degrees of insulin resistance.

METHODS

Thirteen people with obesity (body mass index, 39.1 kg/m 2 ; range, 30.0-45.1 kg/m 2 ) with varying degrees of insulin resistance (Homeostatic Model Assessment of Insulin Resistance, 5.2; range, 0.7-11.6) consumed novel flavored-colored yogurts that were sweetened with either sugar or monkfruit daily for 6 days to assess whether when given the choice of sugar-sweetened versus monkfruit-sweetened yogurts to consume, participants preferred sugar-sweetened yogurts.

RESULTS

Participants consumed a greater amount ( p = .009) and percentage ( p = .04) of sugar-sweetened yogurt earned than monkfruit-sweetened yogurt. The percent of sugar-sweetened versus monkfruit-sweetened yogurt consumed in relationship to amount earned was related to insulin resistance ( r = 0.64, p = .019), glycated hemoglobin ( r = 0.61, p = .027), insulin ( r = 0.58, p = .007), and glucose ( r = 0.56, p = .048).

CONCLUSIONS

Insulin resistance is associated with preference for sugar-sweetened foods in participants with obesity, which may make it hard to make dietary changes. Research is needed to assess whether treatments that improve insulin resistance also change the preference for sugar-sweetened or high-glycemic-index foods.

Measurement is the foundation of research and theory on children's eating behaviours: Current issues and directions for progress

Eating behaviours affect food intakes and are involved in the aetiology of obesity. There has been impetus to translate findings about children's eating behaviour into intervention and policy programs. However, measurement limitations have hindered our capacity to understand and influence children's eating behaviours. In the present paper we provide an overview of some of the key methodological and measurement issues facing the field of children's eating behaviours and highlight implications for research and health promotion. Drawing on insight from parallel issues that occur in the measurement of early social and emotional development, we examine two overlapping themes in children's (aged 0-∼12 years) eating behaviours (Somaraki et al., 2021) measurement issues related to validity and reliability, and (Steinsbekk & Wichstrøm, 2015) associated methodological challenges, such as contextual influences and the importance of designing studies that use multiple informants and multiple methods. We then suggest insights and strategies aimed at advancing approaches to measurement of children's eating behaviours. To progress our understanding of children's eating behaviours, we conclude that a range of psychometrically sound, fit-for-purpose measurement instruments and procedures are needed for use in multi-trait, multi-method, multi-informant studies in a range of populations and contexts.

The propensity to sign-track is associated with externalizing behavior and distinct patterns of reward-related brain activation in youth

Externalizing behaviors in childhood often predict impulse control disorders in adulthood; however, the underlying bio-behavioral risk factors are incompletely understood. In animals, the propensity to sign-track, or the degree to which incentive motivational value is attributed to reward cues, is associated with externalizing-type behaviors and deficits in executive control. Using a Pavlovian conditioned approach paradigm, we quantified sign-tracking in 40 healthy 9-12-year-olds. We also measured parent-reported externalizing behaviors and anticipatory neural activations to outcome-predicting cues using the monetary incentive delay fMRI task. Sign-tracking was associated with attentional and inhibitory control deficits and the degree of amygdala, but not cortical, activation during reward anticipation. These findings support the hypothesis that youth with a propensity to sign-track are prone to externalizing tendencies, with an over-reliance on subcortical cue-reactive brain systems. This research highlights sign-tracking as a promising experimental approach delineating the behavioral and neural circuitry of individuals at risk for externalizing disorders.

Child Weight Status: The Role of Feeding Styles and Highly Motivated Eating in Children

Although parental feeding plays an important role in child eating and weight status, high food motivation among children may also be a factor shaping how feeding impacts child weight. This study explored whether individual differences in preschool children’s food motivation interacted with mothers’ feeding styles in predicting subsequent child weight status. Participants included 129 Hispanic Head Start mother/child dyads. Data were collected at ages 4–5 years (Time 1) and 7–9 (Time 3). Staff measured heights/weights and observed children in an eating in the absence of hunger task. Mothers reported on feeding styles/practices and children’s eating behaviors. A principal components analysis derived a measure of highly motivated eating in children. Multiple regressions predicted Time 3 child BMI z-scores. Time 3 BMI z-scores were positively predicted by authoritative and indulgent feeding styles and negatively predicted by monitoring. Since feeding style interacted with highly motivated eating, separate regressions were run for high and low food motivation in children. Unexpectedly, results showed that authoritative feeding positively predicted Time 3 child BMI z-scores only for children showing low levels of food motivation. Characterizing differential parental feeding and child eating phenotypes may assist in tailoring childhood obesity prevention programs for the target populations.

Reducing relative food reinforcement of infants using a music enrichment program: a randomized, controlled trial

BACKGROUND

Food reinforcement or one's motivation to eat may be established early in life; it might not be the food reinforcement per se that drives weight gain, but rather the imbalance between food and nonfood reinforcement.

OBJECTIVES

We implemented a 2-y randomized, controlled trial to assess the effects of a music enrichment program (music, n = 45) compared with an active play date control (control, n = 45) in 9- to 15-mo-old healthy infants who were strongly motivated to eat.

METHODS

The 12-mo intensive intervention phase included 4 semesters of Music Together® or a play date program (Winter, Spring, Summer, and Fall), comprised of once per week group meetings, followed by a 12-mo maintenance phase with monthly meetings. Parents were encouraged to listen to the Music Together® program CD or play with the play date group's toy with their infants at home, respectively. We performed a modified intention-to-treat analysis using all randomly assigned, non-excluded subjects for the outcome measures [relative reinforcing value of food (RRVfood), food reinforcement, music reinforcement, and weight-for-length z-score (WLZ)].

RESULTS

There were significant differential group changes across time for RRVfood (group × month; P = 0.016; Cohen's f2 = 0.034). The music group had significantly greater RRVfood decreases than the control group from baseline to the end of the intensive intervention phase (music change = -0.211; control change = -0.015; P = 0.002; Cohen's D = 0.379). However, these differences were not maintained during months 12-24 (music change = -0.187; control change = -0.143; P = 0.448; D = 0.087). We observed an overall moderation effect by sex for food reinforcement and WLZ. Boys in the music group had a significant attenuation in food reinforcement and WLZ compared with boys in the control group.

CONCLUSIONS

This study extends our knowledge in infant eating behavior by providing insight into the role of nonfood alternatives in altering one's motivation to eat. There may be sex differences in altering one's motivation to eat.This trial was registered at clinicaltrials.gov as NCT02936284.

Characteristics of eating behavior profiles among preschoolers with low-income backgrounds: a person-centered analysis

BACKGROUND

Individual differences in eating behaviors among young children are well-established, but the extent to which behaviors aggregate within individuals to form distinct eating behavior profiles remains unknown. Our objectives were to identify eating behavior profiles among preschool-aged children and evaluate associations with temperament and weight.

METHODS

A secondary, cross-sectional analysis of baseline data from 2 cohort studies was conducted involving 1004 children aged 3-4 years and their parents with low-income backgrounds. Children's eating behaviors and temperament were assessed by parental report. Body mass index z-scores and weight status were calculated using measured heights and weights. Latent profile analysis (LPA) was used to generate profiles and bivariate analyses were used to evaluate associations with temperament and weight status.

RESULTS

LPA revealed the presence of 3 eating behavior profiles among children. Children with High Food Approach profiles (21.2%) had lower temperamental inhibitory control and the highest percent of children with obesity relative to the other profiles. Children with High Food Avoidant profiles (35.6%) had lower temperamental impulsivity and lower BMI z-scores relative to the other profiles, whereas children with Moderate Eating profiles (intermediary levels of all behaviors; 43.2%) had higher temperamental inhibitory control and lower anger/frustration, than other profiles.

CONCLUSIONS

Young children's eating behaviors appear to aggregate within individuals to form empirically distinct profiles reflecting food approach, food avoidance, and moderate approaches to eating that are differentiated by aspects of temperament and weight. Future work should seek to understand the extent to which health promotion and obesity prevention approaches should be tailored to take into account children's fundamental dispositions towards eating.

Profiles of Behavioral Self-Regulation and Appetitive Traits in Preschool Children: Associations With BMI and Food Parenting Practices

Appetitive traits that contribute to appetite self-regulation have been shown to relate to non-food-related regulation in general domains of child development. Latent profile analysis (LPA) was used to identify typologies of preschool children's behavioral self-regulation (BSR) and appetitive traits related to appetite self-regulation (ASR), and we examined their relation with children's BMIz and food parenting practices. Participants included 720 children and their parents (90% mothers), drawn from the baseline assessment of a childhood obesity preventive intervention. BSR measures included teacher reports of children's inhibitory control, impulsivity and attentional focusing, as well as an observed measure of inhibitory control. ASR was assessed using parents' reports of children's appetitive traits related to food avoidance (e.g., satiety responsiveness, slowness in eating) and food approach (e.g., enjoyment of food, food responsiveness). Children's body mass index z-score (BMIz) was calculated from measured height and weight. Parents' BMI and food parenting practices were also measured. Four profiles were identified that characterized children with dysregulated behavior, higher food approach and lower food avoidance (16%), dysregulated behavior but lower food approach and higher food avoidance (33%), regulated behavior but highest food approach and lowest food avoidance (16%), and highly-regulated behavior, lowest food approach and highest food avoidance (35%). Children's BMIz was highest in the profile consisting of children with dysregulated behavior, higher food approach and lower food avoidance. BMI was similar in the profile with children with regulated behavior but highest food approach and lowest food avoidance; children in this profile also had parents who reported the highest levels of controlling food parenting practices, and the lowest levels of parental modeling of healthy eating. Compared to all other profiles, children in the profile characterized by highly-regulated behavior, lowest food approach and highest food avoidance had the lowest BMIz and had parents who reported food parenting practices characterized by the highest levels of child control in feeding and the lowest levels of pressure to eat. These findings provide evidence of differing patterns of relations between self-regulation across behavioral and eating domains, and children's obesity risk may vary based on these different patterns.

Are Peripheral Biomarkers Determinants of Eating Styles in Childhood and Adolescence Obesity? A Cross-Sectional Study

Disturbances in eating behaviors have been widely related to obesity. However, little is known about the role of obesity-related biomarkers in shaping habitual patterns of eating behaviors (i.e., eating styles) in childhood. The objective of the present study was to explore the relationships between several biomarkers crucially involved in obesity (ghrelin, insulin resistance, and leptin/adiponectin ratio) and eating styles in children and adolescents with obesity. Seventy participants aged between 8 and 16 (56.2% men) fulfilled the Spanish version of the Dutch Eating Behavior Questionnaire for Children to measure external, emotional, and restrained eating styles. In addition, concentrations of ghrelin, leptin, adiponectin, insulin, and glucose were obtained through a blood test. Hierarchical multiple regression analyses controlling for age and sex were computed for each eating style. Results indicated that individuals with higher ghrelin concentration levels showed lower scores in restrained eating (β = -0.61, p < 0.001). The total model explained 32% of the variance of the restrained pattern. No other relationships between obesity-related biomarkers and eating behaviors were found. This study highlights that one of the obesity-risk factors, namely lower plasma ghrelin levels, is substantially involved in a well-known maladaptive eating style, restraint eating, in childhood obesity.

Predictors of Post-Exercise Energy Intake in Adolescents Ranging in Weight Status from Overweight to Severe Obesity

Exercise may sensitize individuals with overweight and obesity to appetitive signals (e.g., hunger and fullness cues), overriding trait eating behaviors that contribute to overeating and obesity, such as uncontrolled eating. The objective of the current study was to measure predictors of objective ad libitum energy intake at a laboratory-based, post-exercise test-meal in adolescents ranging in weight status from overweight to severe obesity. We hypothesized that appetitive states, rather than appetitive traits, would be the strongest predictors of energy intake at a post-exercise test-meal, after controlling for body size. At Baseline, 30 adolescents (ages 10-16 years, 50% female (F), 43% non-Hispanic white (NHW), 83% with obesity (OB)) completed state and trait appetite measures and an ad libitum dinner meal following intensive exercise. Nineteen of those participants (47% F, 32% NHW, 79% OB) completed identical assessments two years later (Year 2). Energy intake (kcal) at each time point was adjusted for fat-free mass index (i.e., body size). Adjusted energy intake was reliable from Baseline to Year 2 (ICC = 0.84). Multiple pre-meal appetite ratings were associated with test-meal energy intake. In stepwise linear regression models, pre-meal prospective food consumption was the strongest and only significant predictor of test-meal energy intake at both Baseline (R2 = 0.25, p = 0.005) and Year 2 (R2 = 0.41, p = 0.003). Baseline post-exercise energy intake was associated with weight change over two years (R2 = 0.24, p = 0.04), but not with change in fat mass (p = 0.11). Appetitive traits were not associated with weight or body composition change (p > 0.22). State appetite cues were the strongest predictors of post-exercise energy intake, independent of body size. Future studies should examine whether long-term exercise programs enhance responsiveness to homeostatic appetite signals in youth with overweight and obesity, with a goal to reduce excess energy intake and risk for weight gain over time.

Behavioral Economic Approaches to Childhood Obesity Prevention Nutrition Policies: A Social Ecological Perspective

Childhood obesity is a significant public health concern associated with the development of the leading causes of death. Dietary factors largely contribute to childhood obesity, but prevention interventions targeting these factors have reported relatively small effect sizes. One potential explanation for the ineffectiveness of prevention efforts is lack of theoretical grounding. Behavioral economic (BE) theory describes how people choose to allocate their resources and posits that some children place higher value on palatable foods (relative reinforcing value of food) and have difficulty delaying food rewards (delay discounting). These seemingly individual-level decision making processes are influenced by higher-level variables (e.g., environment/policy) as described by the social ecological model. The purpose of this manuscript is to provide a theoretical review of policy-level childhood obesity prevention nutrition initiatives informed by BE. We reviewed two policy-level approaches: (1) incentives-/price manipulation-based policies (e.g., sugary drink tax, SNAP pilot) and (2) healthful choices as defaults (Healthy Hunger Free Kids Act/National School Lunch Program, advertising regulations, default items). We review current literature as well as its limitations and future directions. Exploration of BE theory applications for nutrition policies may help to inform future theoretically grounded policy-level public health interventions.

Evaluation of a child food reward task and its association with maternal feeding practices

Food reward is defined as the momentary value of a food to the individual at the time of ingestion and is characterised by two psychological processes-"liking" and "wanting". We aimed to validate an age-appropriate food reward task to quantify implicit wanting of children from the GUSTO cohort (n = 430). At age 5 years, child appetitive traits and maternal feeding practices were reported by mothers via questionnaires. At age 6, a write-for-food task based on the child's preference for food or toy rewards was undertaken in laboratory conditions. Child BMI and skinfold measurements were taken at age 7. Convergent validity of the food reward task was assessed by associating with child appetitive traits, where enjoyment of food/food responsiveness (OR: 1.51; 95% CI: 1.06, 2.15) and emotional overeating (OR: 1.64; 95% CI: 1.09, 2.48) were positively associated with high food reward in children. Criterion validity was tested by associating with child BMI, however no significant relationships were observed. Multivariable logistic regression analysis with maternal feeding practices revealed that children whose mother tend to restrict unhealthy food (OR: 1.37; 95% CI: 1.03, 1.82) and girls whose mothers taught them about nutrition (OR: 2.09; 95% CI: 1.19, 3.67) were more likely to have high food reward. No further significant associations were observed between food reward, other appetitive traits and feeding practices. Despite the lack of association with child weight status, this study demonstrated the value of the write-for-food task to assess food reward in children and presented sex-specific associations with maternal feeding practices.

Food reinforcement and habituation to food are processes related to initiation and cessation of eating

An individual bout of eating involves cues to start eating, as well as cues to terminate eating. One process that determines initiation of eating is food reinforcement. Foods with high reinforcing value are also likely to be consumed in greater quantities. Research suggests both cross-sectional and prospective relationships between food reinforcement and obesity, food reinforcement is positively related to energy intake, and energy intake mediates the relationship between food reinforcement and obesity. A process related to cessation of eating is habituation. Habituation is a general behavioral process that describes a reduction in physiological or affective response to a stimulus, or a reduction in the behavioral responding to obtain a stimulus. Repeated exposure to the same food during a meal can result in habituation to that food and a reduction in consumption. Habituation is also cross-sectionally and prospectively related to body weight, as people who habituate slower consume more in a meal and are more overweight. Research from our laboratory has shown that these two processes independently influence eating, as they can account for almost 60% of the variance in ad libitum intake. In addition, habituation phenotypes show reliable relationships with reinforcing value, such that people who habituate faster also find food less reinforcing. Developing a better understanding of cues to start and stop eating is fundamental to understanding how to modify eating behavior. An overview of research on food reinforcement, habituation and food intake for people with a range of weight status and without eating disorders is provided, and ideas about integrating these two processes that are related to initiation and termination of a bout of eating are discussed.

The Relative Reinforcing Value of Cookies Is Higher Among Head Start Preschoolers With Obesity

The relative reinforcing value (RRV) of food measures how hard someone will work for a high-energy-dense (HED) food when an alternative reward is concurrently available. Higher RRV for HED food has been linked to obesity, yet this association has not been examined in low-income preschool-age children. Further, the development of individual differences in the RRV of food in early childhood is poorly understood. This cross-sectional study tested the hypothesis that the RRV of HED (cookies) to low-energy-dense (LED; fruit) food would be greater in children with obesity compared to children without obesity in a sample of 130 low-income 3- to 5-year-olds enrolled in Head Start classrooms in Central Pennsylvania. In addition, we examined individual differences in the RRV of food by child characteristics (i.e., age, sex, and reward sensitivity) and food security status. The RRV of food was measured on concurrent progressive-ratio schedules of reinforcement. RRV outcomes included the last schedule reached (breakpoint) for cookies (cookie Pmax) and fruit (fruit Pmax), the breakpoint for cookies in proportion to the total breakpoint for cookies and fruit combined (RRV cookie), and response rates (responses per minute). Parents completed the 18-item food security module to assess household food security status and the Behavioral Activation System scale to assess reward sensitivity. Pearson's correlations and mixed models assessed associations between continuous and discrete child characteristics with RRV outcomes, respectively. Two-way mixed effects interaction models examined age and sex as moderators of the association between RRV and Body Mass Index z-scores (BMIZ). Statistical significance was defined as p < 0.05. Children with obesity (17%) had a greater cookie Pmax [F (1, 121) = 4.95, p = 0.03], higher RRV cookie [F (1, 121) = 4.28, p = 0.04], and responded at a faster rate for cookies [F (1, 121) = 17.27, p < 0.001] compared to children without obesity. Children with higher cookie response rates had higher BMIZ (r = 0.26, p < 0.01); and RRV cookie was positively associated with BMIZ for older children (5-year-olds: t = 2.40, p = 0.02) and boys (t = 2.55, p = 0.01), but not younger children or girls. The RRV of food did not differ by household food security status. Low-income children with obesity showed greater motivation to work for cookies than fruit compared to their peers without obesity. The RRV of HED food may be an important contributor to increased weight status in boys and future research is needed to better understand developmental trajectories of the RRV of food across childhood.

Genetic variation of the dopamine D2 receptor gene: association with the reinforcing value of food and eating in the absence of hunger in Chilean children

Introduction

Background: food is a powerful reinforcer that motivates people to eat. The TaqI A1 polymorphism (rs1800497; T>C) downstream of the dopamine D2 receptor (DRD2) gene has been associated with diminished DRD2 receptor density, higher food reinforcement, and impaired eating behavior in adults. Objective: to evaluate the association between the rs1800497 polymorphism and the reinforcing value of food and eating in the absence of hunger in Chilean children. Material and method: nineteen Chilean children (aged 8-12 years) who were carriers of the A1-allele and 19 age- and gender-matched non-carriers (A2-allele) were evaluated on the reinforcing value of food and eating in the absence of hunger. Anthropometric measures were performed by standard procedures. Briefly, children received a standard pre-load lunch followed by an ad-libitum exposure to palatable foods. Results: no differences were found between A1-allele carriers and non-carriers, whether obese or non-obese, in ad libitum energy intake, macronutrient consumption, or the relative reinforcing value of food (p > 0.05). In obese children, A1 carriers reported significantly lower satiety and fullness before lunch (p < 0.05). However, in children with normal weight A1 carriers were found to exhibit trends for greater satiety and fullness before lunch when compared to non-carriers, but this trend reversed after lunch such that carriers exhibited lower satiety and fullness (p = 0.06). Conclusions: although TaqI A1 may play an important role in some eating behavior-related traits such as satiety and fullness, especially in obese children, our findings indicate that this polymorphism does not appear to affect eating in the absence of hunger or food reinforcement in children.

Infants with big appetites: The role of a nonfood environment on infant appetitive traits linked to obesity

BACKGROUND

Individual differences in appetitive traits present in the first few weeks of life. Research has shown that infants with a greater food reinforcement ratio (FRR) have higher obesity risk. To date, limited work has examined the relation between FRR and appetitive traits of infants, and how FRR relates to appetitive traits and obesity development.

OBJECTIVES

To examine the relation between appetitive traits and food and nonfood reinforcement of infants aged 9-18 mo, and to examine whether food and nonfood reinforcement mediate the relation between appetitive traits and weight-for-length z-score (zWFL).

METHOD

This secondary data analysis was conducted by combining 4 different cohorts of infants (n = 143) who have complete data on the food/nonfood reinforcement task, Baby Eating Behavior Questionnaire, and anthropometrics and demographics assessments. Three different nonfood reinforcers were used: video (DVD; n = 27), playing with bubbles (Bubbles; n = 67), and music accompanied by instruments (Music; n = 49) for the nonfood portion of the task. For the food portion of the task, the infant's favorite food was used.

RESULTS

General appetite positively correlated with FRR and zWFL, but negatively correlated with nonfood reinforcement; satiety responsiveness negatively correlated with food reinforcement, FRR, and zWFL. Mediational analysis showed that effects of general appetite on zWFL were mediated by FRR (indirect effect = 0.100, 95% CI: 0.041, 0.187) and nonfood reinforcement (indirect effect = 0.076, 95% CI: 0.025, 0.156). We also observed the mediating effect of FRR on the relation of satiety responsiveness and zWFL (indirect effect = -0.097, 95% CI: -0.204, -0.026).

CONCLUSIONS

Our work contributes to the mechanistic understanding of the ontogeny of obesity development early in life among individuals who are born with appetitive drive for overconsumption. During early infancy, the nonfood environment may protect against this drive and prevent obesity development.

Behavioral and physiological characteristics associated with learning performance on an appetitive probabilistic selection task

Individuals show meaningful variability in food choices. Choices are affected by individual differences in sensitivity to food reward and punishment, so understanding correlates of response to food reinforcement can help characterize food choices. Here, we examined behavioral and physiological correlates of individual differences in how individuals learn from food reward and punishment, as measured by performance on an appetitive probabilistic selection task that used sweet and bitter tastes as reinforcement. Sensitivity to food reward, sensitivity to food punishment, and overall learning performance were measured in 89 adults. Multivariate linear regressions were used to test if variables including body mass index (BMI), external eating, emotional eating, behavioral inhibition/behavioral activation scales (BIS/BAS), and perceived sensitivity to reward and punishment (SPQ/SRQ) were associated with measures of learning performance. External eating (β=-.035, p=.019), BIS (β=-.066, p=.004), and SPQ (β=.003, p=.023) were associated with overall learning performance. BMI (β=-.000, p=.012), emotional eating (β=.055, p=.006), and external eating (β=-.062, p=.004) were associated with sensitivity to food reward. No variables were associated with sensitivity to food punishment. In post hoc analyses, the interaction of sex and SPQ was associated with overall performance (β=-.005, p=.025), such that the relationship was positive in women only (β=.006, p=0.002). Results support that, controlling for key individual characteristics, BMI and susceptibility to food cues are associated with lower sensitivity to food reward, which may affect future food choices and eating behavior.

No evidence for an association between obesity and milkshake liking

BACKGROUND

Prevailing models of obesity posit that hedonic signals override homeostatic mechanisms to promote overeating in today's food environment. What researchers mean by "hedonic" varies considerably, but most frequently refers to an aggregate of appetitive events including incentive salience, motivation, reinforcement, and perceived pleasantness. Here we define hedonic as orosensory pleasure experienced during eating and set out to test whether there is a relationship between adiposity and the perceived pleasure of a palatable and energy-dense milkshake.

METHODS

The perceived liking, wanting, and intensity of two palatable and energy-dense milkshakes were assessed using the Labeled Hedonic Scale (1), visual analog scale (VAS), and Generalized Labeled Magnitude Scale (2) in 110 individuals ranging in body mass index (BMI) from 19.3 to 52.1 kg/m². Waist circumference, waist-hip ratio, and percent body fat were also measured. Importantly, unlike the majority of prior studies, we attempted to standardize internal state by instructing participants to arrive to the laboratory neither hungry nor full and at least 1-h fasted. Data were analyzed with general linear and linear mixed effects models (GLMs). Hunger ratings were also examined prior to hedonic measurement and included as covariates in our analyses.

RESULTS

We identified a significant association between ratings of hunger and milkshake liking and wanting. By contrast, we found no evidence for a relationship between any measure of adiposity and ratings of milkshake liking, wanting, or intensity.

CONCLUSIONS

We conclude that adiposity is not associated with the pleasure experienced during consumption of our energy-dense and palatable milkshakes. Our results provide further evidence against the hypothesis that heightened hedonic signals drive weight gain.

Development of a measure of the relative reinforcing value of food versus parent-child interaction for young children

The relative reinforcing value (RRV) of food captures individual differences in the motivation to eat and is associated with weight status among infants, children, and adults. Currently, there is no concurrent measure of the RRV of food versus a non-food alternative for 4-to-5-year-old children. The present study aimed to develop and validate a measure of the RRV of food versus time spent interacting with a parent in the context of reading among 4-to-5-year-old children. The first phase of the study involved an online survey. Parents of 4-to-5 year olds (n = 102) reported their children's consumption frequency and liking for thirty-six snack foods. A priori criteria were used to identify snacks that were well-liked and served at least sometimes for use in the subsequent laboratory study. Then, a validation study was conducted in the laboratory to examine the construct validity of the finalized RRV task. Thirty-one parent-child dyads completed a laboratory visit, in which children's RRV of food versus time spent reading with a parent was measured concurrently on a progressive ratio reward schedule. Linear regression was used to assess validity of the task. Children's RRV of food positively and significantly predicted BMI z-scores among children with complete data (B = 0.41, p < 0.05, n = 28). Maximum schedules reached for food also positively and significantly predicted BMI z-scores (B = 0.30, p < 0.05). The relationship between maximum schedules reached for parent-child reading and BMI z-scores was in the expected direction, but this relationship was non-significant. Results support the validity and feasibility of the RRV paradigm used in the present study. Future research could continue to examine the measurement properties of this paradigm, as well as the potential for positive parent-child interactions to serve as a novel alternative to food.

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.

The reinforcing value of food and non-food alternative: Associations with BMI z-score and percent fat mass

There is growing evidence of an association between the relative reinforcing value of food (RRVF; how hard a child is willing to work for a food versus a non-food reinforcer) and weight across many life stages, but few studies have examined this association among preschool age children. This study investigated the association between the RRVF (measured as the food reinforcing ratio (FRR)) and body mass index (BMI) z-score and percent fat mass (%FM), in 3 year-old children. The sample was comprised of 33 children who were 3 years of age (36-47 months). Children selected their favourite food reinforcer (cookie) and non-food (audiobook) reinforcer to be used in the FRR task, which was delivered using a sequential progressive fixed ratio reward schedule. Child height, weight and percent body fat using bioelectrical impedance analysis were assessed by trained research staff. Linear regression analyses showed that FRR was significantly and positively associated with BMI z-scores. FRR was not significantly associated with %FM. Findings from this study support the RRVF as a potential risk factor in the development of childhood obesity. Longitudinal research involving larger sample sizes would strengthen future research exploring associations between RRVF and body composition in preschool age children.

Trait-level facets of impulsivity and momentary, naturalistic eating behavior in children and adolescents with overweight/obesity

Impulsivity, and specific subdomains of inhibitory control and reward sensitivity, are trait-level factors that have been implicated in the onset and maintenance of pediatric obesity and disordered eating, but their associations with real-world eating behavior are unknown. We investigated associations of these trait-level constructs with naturalistic, momentary measures of loss of control (LOC) eating and overeating severity in a heterogeneous sample of youth (n = 40), aged 8-14y, with overweight/obesity. Self-report, parent-report, and behavioral data on trait-level impulsivity, reward sensitivity, and inhibitory control, respectively, were collected in the context of a 14-day ecological momentary assessment (EMA) protocol in which participants reported on their eating behavior, mood, hunger, and palatability of foods consumed in real-time. Generalized estimating equations revealed that more perseverative errors on a behavioral measure of visuomotor processing speed and a lower self-reported tendency to act without thinking (at a trend level) were related to greater overall LOC severity. Momentary associations between negative affect and LOC severity were stronger among individuals with greater perseverative errors. Results suggest that trait-level facets of impulsivity may directly influence an individual's tendency to engage in dysregulated eating behaviors, and may also impact susceptibility to state-level factors associated with occurrence of these behaviors. Momentary interventions for LOC eating may require tailoring to address temperamental factors related to impulsivity and inhibitory control.

Behavioral phenotypes for childhood obesity: 2017 Alan N. Epstein Research Award

The percentage of children in the United States with obesity has more than tripled since the 1970s. Despite considerable work in this area, there has been limited success in the long-term treatment and prevention of childhood obesity. In order for intervention approaches to be successful, it will be crucial to study individual variation and the underlying mechanisms that impact human ingestive behavior. Research in my laboratory has focused on identifying behavioral phenotypes for childhood obesity which may be used to develop targeted intervention approaches that are tailored to a child's individual predisposition. This work has included studying select appetitive traits among weight-discordant siblings and unrelated children to elucidate potential differences in children's ability to regulate short-term energy intake and susceptibility to eating in response to food cues in the environment. I am greatly honored to be the recipient of the 2017 Alan N. Epstein Research Award from the Society for the Study of Ingestive Behavior (SSIB). I want to acknowledge and express my sincere gratitude to my mentors and colleagues who have supported me and provided guidance throughout my research career and to my research team and students for their hard work on our studies.

Identifying behavioral phenotypes for childhood obesity

Existing programs which aim to prevent and treat childhood obesity often do not take into account individual variation and the underlying mechanisms that impact child eating behavior. Individual differences in children's appetitive traits have been shown to appear as early as during infancy and become more pronounced as children grow older and become more exposed to the obesogenic food environment. Differences in genetic predispositions interacting with factors in children's early environment account in part for individual differences in appetitive traits. It is very likely that obesogenic eating phenotypes manifest themselves before the onset of childhood obesity. If so, identifying these phenotypes early is expected to move primary prevention strategies in a new direction and holds great potential to significantly enhance our ability to prevent childhood obesity. The aim of this narrative review is to discuss the role of behavioral phenotyping as an innovative approach for the development of more personalized obesity prevention and treatment interventions that are tailored to children's individual predispositions. We describe several examples of appetitive traits which have been linked to overeating and excess weight gain in children and thus may represent modifiable risk factors for future interventions. The review concludes with a comprehensive synthesis of opportunities for future human ingestive behavior research on identifying behavioral phenotypes for childhood obesity.

Using food as a reward: An examination of parental reward practices

Eating patterns and taste preferences are often established early in life. Many studies have examined how parental feeding practices may affect children's outcomes, including food intake and preference. The current study focused on a common food parenting practice, using food as a reward, and used Latent Profile Analysis (LPA) to examine whether mothers (n = 376) and fathers (n = 117) of children ages 2.8 to 7.5 (M = 4.7; SD = 1.1) grouped into profiles (i.e., subgroups) based on how they use of food as a reward. The 4-class model was the best-fitting LPA model, with resulting classes based on both the frequency and type of reward used. Classes were: infrequent reward (33%), tangible reward (21%), food reward (27%), and frequent reward (19%). The current study also explored whether children's eating styles (emotional overeating, rood fussiness, food responsiveness, and satiety responsiveness) and parenting style (Authoritative, Authoritarian, and Permissive) varied by reward profile. Analyses of Variance (ANOVA) revealed that the four profiles differed significantly for all outcome variables except satiety responsiveness. It appears that the use of tangible and food-based rewards have important implications in food parenting. More research is needed to better understand how the different rewarding practices affect additional child outcomes.

Repeatability of the infant food reinforcement paradigm: Implications of individual and developmental differences

The relative reinforcing value of food versus engagement in other behaviors may be related to the development of obesity, and interventions to reduce FRR may prevent the development of obesity. Our laboratory recently developed a paradigm to measure the reinforcing value of food versus an alternative behavior (i.e., playing with bubbles) in infants using a computerized laboratory task, during which infants press a button to earn reinforcers following a progressive ratio schedule of reinforcement. The primary purpose of this study was to examine the short-term (within 2 weeks) repeatability of this measure, specifically the outcome of infant food reinforcing ratio (FRR), or how hard infants will work for food relative to the alternative. The secondary aim was to examine whether infant age and temperament dimensions related to novelty responsiveness (high intensity pleasure and approach) moderated the repeatability of FRR. Thirty-seven infants aged 9-18 months completed this study. Repeated measures analysis of variance (ANOVA) showed no differences between time 1 and time 2 in responding for food (F = 0.463, p = 0.501), bubbles (F = 1.793, p = 0.189), or overall FRR (F = 0.797, p = 0.378). Regression models showed the association between BUB P_max at time 1 and time 2 were moderated by infant age (p = 0.04), with greater repeatability in older infants. Linear regression models also demonstrated that the infant temperamental dimension of high intensity pleasure significantly predicted BUB P_max at time 1 (β = 2.89, p = 0.01), but not at time 2. Overall, our findings support the repeatability of this measure for food portion of the reinforcement task, but demonstrated that the measure of non-food portion of the task required modification, in particular among children younger than 13 months old.

Relative reinforcing value of food and delayed reward discounting in obesity and disordered eating: A systematic review

Understanding the food choice decision-making may help identify those at higher risk for excess weight gain and dysregulated eating patterns. This paper systematically reviews the literature related to eating behavior and behavioral economic constructs of relative reinforcing value of food (RRV_food) and delayed reward discounting (DRD). RRV_food characterizes how valuable energy-dense food is to the individual, and DRD characterizes preferences for smaller immediate rewards over larger future rewards, an index of impulsivity. Literature search on PubMed was conducted using combination of terms that involve behavioral economics and dysregulated eating in youth and adults. Forty-seven articles were reviewed. There is consistent evidence that obese youth and adults exhibit higher RRV_food. There is a need for more research on the role of RRV_food in eating disorders, as an insufficient number of studies exist to draw meaningful conclusions. There is accumulating evidence that obese individuals have higher DRD but the study of moderators of this relationship is crucial. Only a small number of studies have been conducted on DRD and binge eating, and no clear conclusions can be made currently. Approximately half of existing studies suggest lower DRD in individuals with anorexia nervosa. Research implications and treatment application are discussed.

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.

Can a Toy Encourage Lower Calorie Meal Bundle Selection in Children? A Field Experiment on the Reinforcing Effects of Toys on Food Choice

The goal of this research was to test whether including an inexpensive nonfood item (toy) with a smaller-sized meal bundle (420 calories), but not with the regular-sized meal bundle version (580 calories), would incentivize children to choose the smaller-sized meal bundle, even among children with overweight and obesity. Logistic regression was used to evaluate the effect in a between-subjects field experiment of a toy on smaller-sized meal choice (here, a binary choice between a smaller-sized or regular-sized meal bundles). A random sample of 109 elementary school children from two schools in the Tucson, Arizona metropolitan area (55 females; Mage = 8.53 years, SDage = 2.14; MBMI = 18.30, SDBMI = 4.42) participated. Children's height and weight were measured and body-mass-index (BMI) was calculated, adjusting for age and sex. In our sample, 21 children were considered to be either overweight or obese. Logistic regression was used to evaluate the effect of a toy on smaller-sized meal choice. Results revealed that the inclusion of a toy with a smaller-sized meal, but not with the regular-sized version, predicted smaller-sized meal choice (P < .001), suggesting that children can be incentivized to choose less food when such is paired with a toy. BMI neither moderated nor nullified the effect of toy on smaller-sized meal choice (P = .125), suggesting that children with overweight and obesity can also be incentivized to choose less. This article is the first to suggest that fast-food restaurant chains may well utilize toys to motivate children to choose smaller-sized meal bundles. Our findings may be relevant for consumers, health advocates, policy makers, and marketers who would benefit from a strategy that presents healthier, but still desirable, meal bundle options.

Cookie or fruit? Relative reinforcing value of snack foods among preschoolers with overweight/obesity compared to healthy weight

The reinforcing value of food is an important determinant of food intake. Research has yet to examine the relative reinforcing value (RRV) of snack foods in young children with overweight and obesity (OW/OB). The current study compared the RRV of high-energy dense foods (cookies) to low-energy dense foods (fruits) between preschoolers with OW/OB and healthy weight (HW). RRV of cookies and fruits in preschoolers with OW/OB (n = 30; M_age = 4.4 ± 0.84; 60% male) and HW (n = 30; M_age = 4.5 ± 0.85; 70% male) was assessed with a developmentally-tailored computer program which used a progressive fixed ratio reward schedule. The results showed that the RRV of cookies was significantly higher for preschoolers with OW/OB compared to HW while the RRV of fruits was significantly higher for preschoolers with HW compared to OW/OB. These results suggest that cookies are more reinforcing for preschoolers with OW/OB and less reinforcing for preschoolers with HW. Finding ways to reduce the reinforcing value of high-energy dense snack foods and identify alternatives that are as reinforcing for preschoolers is a challenge for weight control treatments.

Association of the dopamine D2 receptor rs1800497 polymorphism and eating behavior in Chilean children

OBJECTIVES

Studies have established a strong genetic component in eating behavior. The TaqI A1 polymorphism (rs1800497) has previously been associated with obesity and eating behavior. Additionally, this polymorphism has been associated with diminished dopamine D2 receptor (DRD2) density, higher body mass, and food reinforcement. The aim of this study was to evaluate the association between the DRD2 rs1800497 polymorphism and eating behavior in Chilean children.

METHODS

This was a cross-sectional study in which we selected 258 children (44% girls, 56% boys; ages 8-14 y) with a wide variation in body mass index. Anthropometric measurements were performed by standard procedures. Eating behavior was assessed using the Eating in Absence of Hunger Questionnaire (EAHQ), Child Eating Behavior Questionnaire, and the Food Reinforcement Value Questionnaire. Genotype of the rs1800497 was determined by polymerase chain reaction-restriction fragment length polymorphism. Association of the TaqI A1 variant (T allele) with eating behavior was assessed using nonparametric tests.

RESULTS

Compared with normal-weight children, the obese group demonstrated higher scores on the External Eating and Fatigue/Boredom subscales of the EAHQ. Higher scores were assessed in Food Responsiveness, Emotional Overeating, Enjoyment to Food and Desire to Drink subscales (P < 0.001) and lower scores of the Satiety Responsiveness and Slowness in Eating (P < 0.05). In the sex-specific analysis, the TaqI A1 allele was associated with higher scores on Satiety Responsiveness and Emotional Undereating subscales in obese girls, and higher scores of Enjoyment of Food subscale in boys.

CONCLUSION

The TaqI A1 polymorphism may be a risk factor for eating behavior traits that may predispose children to greater energy intake and obesity.

Infant Temperament Is Associated with Relative Food Reinforcement

OBJECTIVE

Food reinforcement refers to how hard someone is motivated to work to gain access to food. Infant temperament is defined as behavioral styles, or constitutionally based individual differences in reactive and regulatory aspects of behavior. Identifying correlates of food reinforcement, such as infant temperament, may help identify infants at risk for future negative health consequences (e.g., overweight or obesity) of high food reinforcement.

METHODS

This study tested aspects of parent-reported negative reactivity and regulation and their associations with relative food reinforcement in a cross-sectional sample of 105 9- to 18-month-old infants. Hierarchical linear regression models were then used to predict infant food reinforcement for the temperament dimensions that were significantly related to it.

RESULTS

Two temperament dimensions, cuddliness (regulatory aspect) (B = -0.050, ΔR² = 0.074, p = 0.005) and rate of recovery from distress and arousal (reactive aspect) (B = -0.040, ΔR² = 0.045, p = 0.031), were inversely associated with relative food reinforcement.

CONCLUSION

Clarifying the nature of relationships between these two behavioral predictors, infant temperament and relative food reinforcement, and early obesity can elucidate the role of individual differences in early obesity risk and can further inform targets for early behavioral obesity preventive interventions.

Behavioral Economic Factors Related to Pediatric Obesity

Behavioral economics (BE) suggests that food and activity choices are governed by costs, available alternatives, and reinforcement. This article reviews basic, translational, and intervention research using a BE framework with overweight or obese children up to age 18. We address BE concepts and methods, and discuss developmental issues, the continuum of BE intervention approaches, findings of studies focused on increasing the cost of unwanted behaviors (ie, energy-dense food intake and sedentary behavior) and decreasing the cost of desired behaviors (ie, healthy food intake and PA), and our team's recent basic behavioral studies using BE approaches with minority adolescents.

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.

Reducing relative food reinforcement in infants by an enriched music experience

OBJECTIVE

The reinforcing value of food may be established early in life. Research shows that infant weight status is related to the relative reinforcing value of food versus non-food alternatives (food reinforcing ratio, FRR). The purpose of this pilot study was to assess the effects of a 6-week music enhancement program (Music Together®, n = 14) versus an active play date control group (n = 13) on the FRR in 9- to 16-month-old infants who were high in relative food reinforcement.

METHODS

Participating parents and infants attended six weekly 45-min group classes. Parents in the music group and the play date group were encouraged to listen to the Music Together program CD or play with the play date group's toy with their infants at home, respectively.

RESULTS

Intent-to-treat analysis showed a decrease in FRR for infants in the music group (mean ± SD: -0.13 ± 0.13) in comparison to a slight increase in the control group (0.04 ± 0.11) (F[1, 24]  = 11.86, P = 0.002).

CONCLUSIONS

These findings provide evidence that relative reinforcing value of food can be reduced by promoting alternative reinforcers at an early age.

Using food as reinforcer to shape children's non-food behavior: The adverse nutritional effect doubly moderated by reward sensitivity and gender

PURPOSE

Control rules are parental practices that use food, especially those high in fat or sugar, as an instrumental reinforcer to encourage children to behave in a normative manner in non-food domains. Past laboratory experiments show that repeatedly presenting snacks as a reward or associated with adults' attention, increases children's preference for the presented food. This field study aims to examine whether control rules are associated with children's increased everyday intake of food high in sugar/fat, and whether this effect is moderated by individual differences in neurobehavioral sensitivity to reward and in gender.

DESIGN

207 six- to twelve-year-old children's parents reported the children's everyday dietary intake through a food frequency questionnaire and provided information regarding the children's sensitivity to rewards as well as the frequency of enforcing control rules.

RESULTS

Children who lived in families with a high frequency of using control rules exhibited more daily fat, carbohydrate, and total energy intake than did children whose parents use control rules less often. Furthermore, the effect of control rules on dietary pattern was particularly strong for children with high reward sensitivity, especially boys.

CONCLUSIONS

Control rules have adverse consequences on children's nutrition. The moderating effects of sensitivity to reward and gender are consistent to a reinforcement learning process--associating the high-fat/sugar food consumption with social-affective pleasure resulting from performing behavior desired by parents--through which parental control rules contribute to children's maladaptive dietary patterns.

Psychological predictors of opportunistic snacking in the absence of hunger

Increased frequency of eating in the absence of homeostatic need, notably through snacking, is an important contributor to overconsumption and may be facilitated by increased availability of palatable food in the obesogenic environment. Opportunistic initiation of snacking is likely to be subject to individual differences, although these are infrequently studied in laboratory-based research paradigms. This study examined psychological factors associated with opportunistic initiation of snacking, and predictors of intake in the absence of homeostatic need. Fifty adults (mean age 34.5years, mean BMI 23.9kg/m(2), 56% female) participated in a snack taste test in which they ate a chocolate snack to satiation, after which they were offered an unanticipated opportunity to initiate a second eating episode. Trait and behavioural measures of self control, sensitivity to reward, dietary restraint and disinhibited eating were taken. Results showed that, contrary to expectations, those who initiated snacking were better at inhibitory control compared with those who did not initiate. However, amongst participants who initiated snacking, intake (kcal) was predicted by higher food reward sensitivity, impulsivity and BMI. These findings suggest that snacking initiation in the absence of hunger is an important contributor to overconsumption. Consideration of the individual differences promoting initiation of eating may aid in reducing elevated eating frequency in at-risk individuals.

Barratt Impulsivity and Neural Regulation of Physiological Arousal

Background

Theories of personality have posited an increased arousal response to external stimulation in impulsive individuals. However, there is a dearth of studies addressing the neural basis of this association.

Methods

We recorded skin conductance in 26 individuals who were assessed with Barratt Impulsivity Scale (BIS-11) and performed a stop signal task during functional magnetic resonance imaging. Imaging data were processed and modeled with Statistical Parametric Mapping. We used linear regressions to examine correlations between impulsivity and skin conductance response (SCR) to salient events, identify the neural substrates of arousal regulation, and examine the relationship between the regulatory mechanism and impulsivity.

Results

Across subjects, higher impulsivity is associated with greater SCR to stop trials. Activity of the ventromedial prefrontal cortex (vmPFC) negatively correlated to and Granger caused skin conductance time course. Furthermore, higher impulsivity is associated with a lesser strength of Granger causality of vmPFC activity on skin conductance, consistent with diminished control of physiological arousal to external stimulation. When men (n = 14) and women (n = 12) were examined separately, however, there was evidence suggesting association between impulsivity and vmPFC regulation of arousal only in women.

Conclusions

Together, these findings confirmed the link between Barratt impulsivity and heightened arousal to salient stimuli in both genders and suggested the neural bases of altered regulation of arousal in impulsive women. More research is needed to explore the neural processes of arousal regulation in impulsive individuals and in clinical conditions that implicate poor impulse control.

Eating tasty food to cope. Longitudinal association with BMI

The goals of this study were to determine if a change in certain motives to eat highly palatable food, as measured by the Palatable Eating Motives Scale (PEMS), could predict a change in body mass index (BMI) over time, to assess the temporal stability of these motive scores, and to test the reliability of previously reported associations between eating tasty foods to cope and BMI. BMI, demographics, and scores on the PEMS and the Binge Eating Scale were obtained from 192 college students. Test-retest analysis was performed on the PEMS motives in groups varying in three gap times between tests. Regression analyses determined what PEMS motives predicted a change in BMI over two years. The results replicated previous findings that eating palatable food for Coping motives (e.g., to forget about problems, reduce negative feelings) is associated with BMI. Test-retest correlations revealed that motive scores, while somewhat stable, can change over time. Importantly, among overweight participants, a change in Coping scores predicted a change in BMI over 2 years, such that a 1-point change in Coping predicted a 1.76 change in BMI (equivalent to a 10.5 lb. change in body weight) independent of age, sex, ethnicity, and initial binge-eating status (Cohen's f(2) effect size = 1.44). The large range in change of Coping scores suggests it is possible to decrease frequency of eating to cope by more than 1 scale point to achieve weight losses greater than 10 lbs. in young overweight adults, a group already at risk for rapid weight gain. Hence, treatments aimed specifically at reducing palatable food intake for coping reasons vs. for social, reward, or conformity reasons, should help achieve a healthier body weight and prevent obesity if this motive-type is identified prior to significant weight gain.

Origins of food reinforcement in infants

BACKGROUND

Rapid weight gain in infancy is associated with a higher risk of obesity in children and adults. A high relative reinforcing value of food is cross-sectionally related to obesity; lean children find nonfood alternatives more reinforcing than do overweight/obese children. However, to our knowledge, there is no research on how and when food reinforcement develops.

OBJECTIVE

This study was designed to assess whether the reinforcing value of food and nonfood alternatives could be tested in 9- to 18-mo-old infants and whether the reinforcing value of food and nonfood alternatives is differentially related to infant weight status.

DESIGN

Reinforcing values were assessed by using absolute progressive ratio schedules of reinforcement, with presentation of food and nonfood alternatives counterbalanced in 2 separate studies. Two nonfood reinforcers [Baby Einstein-Baby MacDonald shows (study 1, n = 27) or bubbles (study 2, n = 30)] were tested against the baby's favorite food. Food reinforcing ratio (FRR) was quantified by measuring the reinforcing value of food (Food Pmax) in proportion to the total reinforcing value of food and a nonfood alternative (DVD Pmax or BUB Pmax).

RESULTS

Greater weight-for-length z score was associated with a greater FRR of a favorite food in study 1 (FRR-DVD) (r = 0.60, P < 0.001) and FRR of a favorite food in study 2 (FRR-BUB) (r = 0.49, P = 0.006), primarily because of the strong association between greater weight-for-length z score and lower DVD Pmax (r = -0.71, P < 0.0001) and BUB Pmax (r = -0.53, P = 0.003). Infant monthly weight gain was positively associated with FRR-DVD (r = 0.57, P = 0.009) and FRR-BUB (r = 0.37, P = 0.047).

CONCLUSIONS

Our newly developed paradigm, which tested 2 different nonfood alternatives, demonstrated that lean infants find nonfood alternatives more reinforcing than do overweight/obese infants. This observation suggests that strengthening the alternative reinforcers may have a protective effect against childhood obesity.

Right sizing prevention. Food portion size effects on children's eating and weight

Experimental findings provide consistent evidence that increasing the portion size of palatable, energy dense entrees relative to an age appropriate reference portion increases children's energy intake of the entree and the meal. Most of these studies have been conducted on preschool aged children between 2 and 6 years of age, in childcare or laboratory settings, using repeated measures designs. In these studies, children's intake is compared across a series of meals, where the size of the entrée portion is varied and other aspects of the meal, including the portion size of other items on the menu, are held constant. This paper provides an overview of what we know from this research, what is not known about the effects of portion size on children's intake and weight status, and points to some of the important unanswered questions and gaps in the literature. Lastly, we discuss how individual characteristics may make someone more or less susceptible to large portions of foods and how the palatability of foods may moderate observed associations among portion size, children's intake, and weight status. Future studies that address the gaps identified in this paper are needed to inform policy and to develop effective and efficient interventions to prevent childhood obesity.

Effects of restriction on children’s intake differ by child temperament, food reinforcement, and parent’s chronic use of restriction

Parents’ use of restrictive feeding practices is counterproductive, increasing children’s intake of restricted foods and risk for excessive weight gain. The aims of this research were to replicate Fisher and Birch’s (1999b) original findings that short-term restriction increases preschool children’s (3–5 y) selection, intake, and behavioral response to restricted foods, and to identify characteristics of children who were more susceptible to the negative effects of restriction. The experiment used a within-subjects design; 37 children completed the food reinforcement task and heights/weights were measured. Parents reported on their use of restrictive feeding practices and their child’s inhibitory control and approach. Overall, the findings replicated those of and revealed that the effects of restriction differed by children’s regulatory and appetitive tendencies. Greater increases in intake in response to restriction were observed among children lower in inhibitory control, higher in approach, who found the restricted food highly reinforcing, and who had previous experience with parental use of restriction. Results confirm that the use of restriction does not reduce children’s consumption of these foods, particularly among children with lower regulatory or higher appetitive tendencies.