***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Food reinforcement , or the motivation to eat , has been associated with increased energy intake , greater body weight , and prospect i ve weight gain . Much of the previous research on the reinforcing value of food has focused on the role of dopamine , but it may be worthwhile to examine genetic polymorphisms in the serotonin and opioid systems as these neurotransmitters have been shown to be related to reinforcement processes and to influence energy intake . We examined the relationship among 44 c and i date genetic polymorphisms in the dopamine , serotonin , and opioid systems  , as well as food reinforcement and  body mass index ( BMI ) in a sample of 245 individuals . Polymorphisms in the monoamine oxidase A ( MAOA-LPR ) and serotonin receptor 2A genes ( rs6314 ) moderated the effect of food reinforcement on BMI , accounting for an additional 5 - 10 % variance and revealed a potential role of the single nucleotide polymorphism , rs6314 , in the serotonin 2A receptor as a differential susceptibility factor for obesity . Differential susceptibility describes a factor that can confer either risk or protection depending on a second variable , such that rs6314 is predictive of both high and low BMI based on the level of food reinforcement , while the diathesis stress or dual-gain model only influences one end of the outcome measure . The interaction with MAOA-LPR better fits the diathesis stress model , with the 3.5R/4R allele conferring protection for individuals low in food reinforcement . These results provide new insight into genes theoretically involved in obesity , and support the hypothesis that genetics moderate the association between food reinforcement and BMI The choice of small immediate rewards as opposed to larger delayed rewards , or delay discounting , is an important dimension of impulsive decision making . The inability to delay gratification is related to obesity , as well as other maladaptive behaviors such as substance abuse , problem drinking , smoking , pathological gambling , and risky HIV behaviors . One way to reduce delay discounting ( DD ) may be to use prospect i ve imagery in the form of episodic future thinking ( EFT ) during inter-temporal decision making . We have recently shown that EFT reduces DD and ad libitum energy intake in obese individuals . However , no studies have examined whether the magnitude of the EFT effect differs between lean and overweight/obese individuals . We conducted a within-subject design experiment to compare the efficacy of EFT versus a control task in reducing DD between lean ( N=24 ) and overweight/obese ( N=24 ) women . Participants attended two sessions in which they engaged in either EFT or control episodic thinking during a DD task . We also examined whether individual differences such as trait time perspective , behavioral inhibition or behavioral activation moderated the EFT effect on DD . Results showed EFT  reduced DD similarly for lean and overweight/obese individuals . The EFT effect was moderated by behavioral activation . This suggests EFT is just as effective in reducing impulsive decision making in obese individuals as it is in lean individuals and may be useful in reducing other impulsive obesity related behaviors BACKGROUND Food reinforcement and dopaminergic activity may influence food consumption , but research on whether they interact has not been performed . OBJECTIVE We assessed the effects of food reinforcement and the interaction of food reinforcement with the dopamine transporter ( SLC6A3 ) genotype and the dopamine D(2 ) receptor ( DRD(2 ) ) genotype on energy consumption . DESIGN We studied food-consumption and reinforcing-value-of-food tasks in 88 smokers of European ancestry before they enrolled in smoking-cessation treatment . In the food-consumption task , subjects tasted and consumed 8 snack foods ad libitum . The reinforcing-value-of-food task assessed how hard subjects would work for food . RESULTS Significant interactions between dopamine genotypes and food reinforcement were observed . Subjects high in food reinforcement who lacked an SLC6A3 * 9 allele consumed significantly more calories ( > 150 kcal ; P = 0.015 ) than did subjects low in food reinforcement or those high in food reinforcement who carried at least one SLC6A3 * 9 allele . Similarly , subjects high in food reinforcement who carried at least one DRD(2)*A1 allele consumed > 130 kcal more ( P = 0.021 ) than did subjects low in food reinforcement or those high in food reinforcement who lacked a DRD(2)*A1 allele . There was also a main effect of food reinforcement on energy intake ( P = 0.005 ) , with subjects high in food reinforcement consuming 104 kcal ( or 30 % ) more than did subjects low in food reinforcement . CONCLUSIONS Food reinforcement has a significant effect on energy intake , and the effect is moderated by the dopamine loci SLC6A3 and DRD(2 ) INTRODUCTION A cigarette purchase task ( CPT ) is a behavioral economic measure of the reinforcing value of smoking in monetary terms ( ie , cigarette dem and ) . This study investigated whether cigarette dem and predicted response to contingent monetary rewards for abstinence among individuals with substance use disorders . It also sought to replicate evidence for greater price sensitivity at whole-dollar pack price transitions ( ie , left-digit effects ) . METHODS Participants ( N = 338 ) were individuals in residential substance use disorder treatment who participated in a r and omized controlled trial that compared contingent vouchers to noncontingent vouchers for smoking abstinence . Baseline dem and indices were used to predict number of abstinent days during the 14-day voucher period ( after the reduction lead-in ) and at 1 and 3 months afterward . RESULTS Dem and indices correlated with measures of smoking and nicotine dependence . As measured by elasticity , intensity and O max , higher dem and significantly predicted fewer abstinent exhaled carbon monoxide readings during voucher period for individuals in the noncontingent vouchers condition . Breakpoint exhibited a trend-level association with abstinent exhaled carbon monoxide readings . Dem and indices did not predict abstinence in the contingent vouchers group , and did not predict abstinence at 1- and 3-month follow-ups . Left-digit price transitions were associated with significantly greater reductions in consumption . CONCLUSIONS The association of cigarette dem and with smoking behavior only in the group for whom abstinence was not incentivized indicates that CPT assesses the value of smoking more than the value of money per se and that vouchers counteract the effects of the intrinsic reinforcing value of cigarettes . Results provide initial short-term evidence of predictive validity for the CPT indices . IMPLICATION S This study provides the first evidence of the validity of the CPT for predicting early response to brief advice for smoking cessation plus nicotine replacement in smokers with substance dependence . However , dem and for cigarettes did not predict voucher-based treatment response , indicating that incentives serve as a powerful motivator not to smoke that acts in opposition to the intrinsic reinforcing value of cigarettes and that the indices reflect the value of smoking more than the value of money per se OBJECTIVES To determine if limited ability to delay gratification ( ATDG ) at age 4 years is independently associated with an increased risk of being overweight at age 11 years and to assess confounding or moderation by child body mass index z score at 4 years , self-reported maternal expectation of child ATDG for food , and maternal weight status . DESIGN Longitudinal prospect i ve study . SETTING Ten US sites . PARTICIPANTS Participants in the National Institute of Child Health and Human Development Study of Early Child Care and Youth Development . Main Exposure Ability to delay gratification at 4 years , measured as pass or fail on a vali date d task . OUTCOME MEASURES Overweight at 11 years , defined as a body mass index greater than or equal to the 85th percentile based on measured weight and height . RESULTS Of 805 children , 47 % failed the ATDG task . Using multiple logistic regression , children who failed the ATDG task were more likely to be overweight at 11 years ( relative risk , 1.29 ; 95 % confidence interval , 1.06 - 1.58 ) , independent of income to needs ratio . Body mass index z score at 4 years and maternal expectation of child ATDG for food did not alter the association , but maternal weight status reduced the association significantly . CONCLUSIONS Children with limited ATDG at age 4 years were more likely to be overweight at age 11 years , but the association was at least partially explained by maternal weight status . Further underst and ing of the association between the child 's ATDG and maternal and child weight status may lead to more effective obesity intervention and prevention programs Obese ( n = 20 ) and normal weight ( n = 20 ) children ( 8 - 11 years ) were compared using the delay of gratification paradigm . All children were asked to choose between an immediate reward or a larger delayed ( one day ) reward . Half the children were offered an edible incentive and half a non-edible incentive . Results showed that the obese choose immediate rewards more often than normals only when the incentive was edible . This suggests that deficits in delay of gratification shown by obese children are not generalized dispositions but are specific to food . A second aspect of the study examined preference for food vs non-food items and activities . Normals showed a much stronger preference for non-food items , nutritious foods and non-food related activities than the obese . This suggests that the deficits in delay of gratification shown by the obese children for food related items may be due to the stronger incentive value of these items for them Objective Food reinforcement is cross-sectionally related to body mass index and energy intake in adults , and prospect ively predicts weight gain in children , but there has not been any research study ing food reinforcement as a predictor of  adult weight gain . Design and Methods This study examined whether the relative reinforcing value of food versus sedentary activities , as measured on a progressive ratio schedule , predicts 12 month weight gain .  Dietary disinhibition and  dietary restraint were also examined as potential moderators of this relationship , in a sample of 115 non-obese ( Body Mass Index < 30 ) adults . Results In a hierarchical regression controlling for baseline age and weight , dietary hunger , income , sex and minority status , food reinforcement significantly increased the variance from 6.3 % to 11.7 % ( p = 0.01 ) and predicted weight gain ( p = 0.01 ) . Dietary disinhibition moderated this relationship ( p = 0.02 ) and increased the variance an additional 4.7 % ( p = 0.02 ) , such that individuals with high food reinforcement had greater weight gain if they were also high in disinhibition . Conclusions These results suggest that food reinforcement is a significant contributor to weight change over time , and food reinforcement may have the biggest effect on those who are most responsive to food cues Obesity and cigarette smoking are often cited separately as the top two preventable causes of death in the United States ; however , little research has explored the factors associated with being both obese and a smoker . Delay discounting is a behavioral characteristic that may underlie both of these conditions/behaviors . Delay discounting describes the extent to which an individual discounts the value of an outcome because of a delay in its occurrence . Higher rates of discounting are often considered as an index of impulsivity and have been linked with obesity and cigarette smoking . No research to date has explored  delay discounting  in a sample of obese smokers . For this study , adolescent smokers classified as obese ( body mass index > 95th percentile ) and healthy weight ( body mass index between the 5th and 85th percentiles ) were compared on a laboratory assessment of delay discounting .  Obese smokers  discounted significantly more by delay than healthy weight smokers . This difference remained statistically significant even after controlling for demographic variables that differed across groups . These findings suggest that the relationships between  delay discounting and obesity and cigarette smoking may be additive , such that extreme discounting might proportionally increase the risk of becoming an obese smoker . However , future prospect i ve study is needed to fully determine the veracity of this hypothesis OBJECTIVE To examine the extent to which self-regulatory capacities , measured behaviorally at ages 3 and 5 years , were linked to rapid weight gain in children from age 3 to 12 years . Self-regulation failure , or the inability to control an impulse or behavior , has been implicated as a mechanism in the development of overweight . DESIGN Prospect i ve longitudinal cohort study . SETTING Home and laboratory-based setting s in 10 sites across the United States . PARTICIPANTS Data were drawn from 1061 children as part of the National Institute of Child Health and Human Development Study of Early Child Care and Youth Development . Main Exposure Self-regulatory capacity was measured in 2 behavioral protocol s ; children participated in a self-control procedure at age 3 years and a delay of gratification procedure at age 5 years . MAIN OUTCOME MEASURES Age- and sex-specific body mass index ( BMI ) z scores were calculated based on measured BMI at 6 points . RESULTS Mixed-modeling analyses were used to examine differences in the rate of weight gain over time based on the extent to which children exhibited the ability to self-regulate in the behavioral procedures . Compared with children who showed high self-regulation in both behavioral protocol s at ages 3 and 5 years , children who exhibited a compromised ability to self-regulate had the highest BMI z scores at each point and the most rapid gains in BMI z scores over the 9-year period . Effects of pubertal status were also noted for girls . CONCLUSION Self-regulation failure in early childhood may predispose children to excessive weight gain through early adolescence Binge eating is a core clinical feature of bulimia nervosa ( BN ) . Enhanced rein 
    Output:
    
There is consistent evidence that obese youth and adults exhibit higher RRVfood .
There is accumulating evidence that obese individuals have higher DRD but the study of moderators of this relationship is crucial .
Approximately half of existing studies suggest lower DRD in individuals with anorexia nervosa .