Food reinforcement, delay discounting and obesity

Reducing behavioural risk factors for cancer: An affect regulation perspective

Nearly half of all cancer deaths are attributable to preventable causes, primarily unhealthy behaviours such as tobacco use, alcohol use and overeating. In this review, we argue that people engage in these behaviours, at least in part, as a means of regulating their affective states. To better understand why people engage in these behaviours and how researchers might design interventions to promote the selection of healthier methods for regulating affect, we propose a conceptual model of affect regulation. We synthesise research from both the stress and coping tradition as well as the emotion and emotion regulation tradition, two literatures that are not typically integrated. In so doing, we indicate where researchers have made headway in understanding these behaviours as affect regulation and note how our model could be used to structure future work in a way that would be particularly advantageous to cancer control efforts.

A COMPARISON OF MAZUR'S k AND AREA UNDER THE CURVE FOR DESCRIBING STEEP DISCOUNTERS

Delay discounting describes how a reward loses value as a function of increasing delay to its receipt and has been reliably associated with a variety of vulnerable populations including those with substance use disorders (SUDs). Two commonly used models to assess delay discounting in the field of SUDs include log k derived from Mazur's hyperbolic equation and area under the curve (AUC). In the current study, we compared log k with AUC on delay discounting data obtained from non-treatment seeking, cocaine- and methamphetamine-dependent volunteers. We specifically chose this population in order to obtain a distribution of relatively steep discounters. The results show that the relationship between AUC and log k is better described by a quadratic rather than a linear function. In other words, changes in discounting, as measured by AUC and log k, are reflected differently across a range of obtained responses. Additionally, the distribution of AUC values was skewed, which appears to be more likely among populations exhibiting greater discounting. Finally, closer examination of indifference points revealed that AUC was almost perfectly predicted by the area from the two longest delays, with relatively less input from shorter delays. Given these results, researchers should exercise additional caution when deciding which method to assess discounting data and how final results are to be interpreted, particularly when dealing with relatively high rates of discounting. High rates of discounting are likely in populations with impulsive disorders such as those with SUDs.

Does goal relevant episodic future thinking amplify the effect on delay discounting?

Delay discounting (DD) is the preference for smaller immediate rewards over larger delayed rewards. Research shows episodic future thinking (EFT), or mentally simulating future experiences, reframes the choice between small immediate and larger delayed rewards, and can reduce DD. Only general EFT has been studied, whereby people reframe decisions in terms of non-goal related future events. Since future thinking is often goal-oriented and leads to greater activation of brain regions involved in prospection, goal-oriented EFT may be associated with greater reductions in DD than general goal-unrelated EFT. The present study (n=104, M_age=22.25, SD=3.42; 50% Female) used a between-subjects 2×2 factorial design with type of episodic thinking (Goal, General) and temporal perspective (Episodic future versus recent thinking; EFT vs ERT) as between factors. Results showed a significant reduction in DD for EFT groups (p<0.001, Cohen's d effect size=0.89), and goal-EFT was more effective than general-EFT on reducing DD (p=0.03, d=0.64).

Delay discounting and utility for money or weight loss

Objective

Obesity is related to a bias towards smaller immediate over larger delayed rewards. This bias is typically examined by studying single commodity discounting. However, weight loss often involves choices among multiple commodities. To our knowledge, no research has examined delay discounting of delayed weight loss compared with other commodities.

Methods

We examined single commodity discounting of money and cross commodity discounting of money and weight loss in a sample of 84 adults with obesity or overweight statuses interested in weight loss. The exchange rate between money and weight loss was calculated, and participants completed two delay discounting tasks: money now versus money later and money now versus weight loss later.

Results

Participants discounted weight loss more than money (p < 0.001). When participants were divided into those who preferred weight loss (n = 61) versus money (n = 23), those who preferred money over weight loss discounted weight loss even more than individuals that preferred weight loss (p = 0.003).

Conclusions

Greater discounting of weight loss for those who preferred money suggest that idiosyncratic preferences are related to multiple commodity discounting, and greater discounting of weight loss across all participants provide insight on important challenges for weight control.

Daily exposure to either a high- or low-energy-dense snack food reduces its reinforcing value in adolescents

OBJECTIVE

To examine the impact of daily exposure to a low-energy-dense (LED) or a high-energy-dense (HED) snack food on its reinforcing value (RRV) in adolescents with healthy weight, overweight, or obesity.

METHODS

A parallel-group, randomized trial was used to assess RRV of LED or HED snack food at baseline and again after exposure to that snack food daily for 2 weeks in 77 adolescents, aged 13 to 17 years. Information on eating-related subject characteristics was also collected at baseline.

RESULTS

After 2 weeks of daily exposure, the RRV of the snack foods was significantly reduced in all participants, regardless of energy density or participant weight status. Among individuals who were high in dietary restraint only, those randomized to LED food found their snack food less reinforcing at baseline than those who were randomized to HED food. Baseline eating-related variables also differed as a function of weight status.

CONCLUSIONS

Daily exposure to snack food in adolescents reduces the RRV of that food regardless of snack food energy density or weight status of the adolescent. This finding differs from adults, suggesting that increases in RRV of HED food after repeated exposure may develop after adolescence.

I want to media multitask and I want to do it now: Individual differences in media multitasking predict delay of gratification and system-1 thinking

Media multitasking, the concurrent use of multiple media forms, has been shown to be related to greater self-reported impulsivity and less self-control. These measures are both hallmarks of the need for immediate gratification which has been associated with fast, intuitive 'system-1' decision making, as opposed to more deliberate and effortful 'system-2' decision making. In Study 1, we used the Cognitive Reflection Task (CRT) to examine whether individuals who engage heavily in media multitasking differ from those who are light media multitaskers in their degree of system-1 versus system-2 thinking. In Study 2 we examined whether heavy and light media multitaskers differ in delay of gratification, using the delay discounting measure which estimates the preference for smaller immediate rewards, relative to larger delayed rewards in a hypothetical monetary choice task. We found that heavy media multitaskers were more likely than light media multitaskers to endorse intuitive, but wrong, decisions on the CRT indicating a greater reliance on 'system-1' thinking. Heavy media multitaskers were also willing to settle for less money immediately relative to light media multitaskers who were more willing to wait for the larger delayed reward. These results suggest that heavy media multitaskers have a reactive decision-making style that promotes current desires (money, ease of processing) at the expense of accuracy and future rewards. These findings highlight the potential for heavy media multitaskers to be at risk for problematic behaviors associated with delay discounting - behaviors such as substance abuse, overeating, problematic gambling, and poor financial management.

Maintained Physical Activity Induced Changes in Delay Discounting

Those who discount the subjective value of delayed rewards less steeply are more likely to engage in physical activity. There is limited research, however, showing whether physical activity can change rates of delay discounting. In a two-experiment series, treatment and maintenance effects of a novel, effort-paced physical activity intervention on delay discounting were evaluated with multiple baseline designs. Using a lap-based method, participants were instructed to exercise at individualized high and low effort levels and to track their own perceived effort. The results suggest that treatment-induced changes in discounting were maintained at follow-up for 13 of 16 participants. In Experiment 2, there were statistically significant group-level improvements in physical activity and delay discounting when comparing baseline with both treatment and maintenance phases. Percentage change in delay discounting was significantly correlated with session attendance and relative pace (min/mile) improvement over the course of the 7-week treatment. Implications for future research are discussed.

Gene and environment interaction: Is the differential susceptibility hypothesis relevant for obesity?

The differential susceptibility model states that a given genetic variant is associated with an increased risk of pathology in negative environments but greater than average resilience in enriched ones. While this theory was first implemented in psychiatric-genetic research, it may also help us to unravel the complex ways that genes and environments interact to influence feeding behavior and obesity. We reviewed evidence on gene vs. environment interactions that influence obesity development, aiming to support the applicability of the differential susceptibility model for this condition, and propose that various environmental "layers" relevant for human development should be considered when bearing the differential susceptibility model in mind. Mother-child relationship, socioeconomic status and individual's response are important modifiers of BMI and food intake when interacting with gene variants, "for better and for worse". While only a few studies to date have investigated obesity outcomes using this approach, we propose that the differential susceptibility hypothesis is in fact highly applicable to the study of genetic and environmental influences on feeding behavior and obesity risk.

A behavioral economic analysis of texting while driving: Delay discounting processes

The purpose of the present study was to examine an impulsive decision-making process underlying texting while driving from a behavioral economic perspective. A sample of 108 college students completed a novel discounting task that presented participants with a hypothetical scenario in which, after receiving a text message while driving, they rated the likelihood of replying to a text message immediately versus waiting to reply for a specific period of time. Participants also completed a delay discounting task in which they made repeated hypothetical choices between obtaining a larger amount of money available after a delay and an equal or lesser amount of money available immediately. The results show that the duration of the delay is a critical variable that strongly determines whether participants choose to wait to reply to a text message, and that the decrease in the likelihood of waiting as a function of delay is best described by a hyperbolic delay discounting function. The results also show that participants who self-reported higher frequency of texting while driving discounted the opportunity to reply to a text message at greater rates, whereas there was no relation between the rates of discounting of hypothetical monetary rewards and the frequency of texting while driving. The results support the conclusion that texting while driving is fundamentally an impulsive choice.

Some current dimensions of the behavioral economics of health-related behavior change

Health-related behaviors such as tobacco, alcohol and other substance use, poor diet and physical inactivity, and risky sexual practices are important targets for research and intervention. Health-related behaviors are especially pertinent targets in the United States, which lags behind most other developed nations on common markers of population health. In this essay we examine the application of behavioral economics, a scientific discipline that represents the intersection of economics and psychology, to the study and promotion of health-related behavior change. More specifically, we review what we consider to be some core dimensions of this discipline when applied to the study health-related behavior change. Behavioral economics (1) provides novel conceptual systems to inform scientific understanding of health behaviors, (2) translates scientific understanding into practical and effective behavior-change interventions, (3) leverages varied aspects of behavior change beyond increases or decreases in frequency, (4) recognizes and exploits trans-disease processes and interventions, and (5) leverages technology in efforts to maximize efficacy, cost effectiveness, and reach. These dimensions are overviewed and their implications for the future of the field discussed.

Behavioral economic indicators of drinking problem severity and initial outcomes among problem drinkers attempting natural recovery: a cross-sectional naturalistic study

BACKGROUND AND AIMS

Research using different behavioral economic (BE) and time perspective (TP) measures suggests that substance misusers show greater sensitivity to shorter-term contingencies than normal controls, but multiple measures have seldom been investigated together. This study evaluated the extent to which multiple BE and TP measures were associated with drinking problem severity, distinguished initial outcomes of natural recovery attempts and shared common variance. Hypotheses were (1) that greater problem severity would be associated with greater impulsivity and demand for alcohol and shorter TPs; and (2) that low-risk drinking would be associated with greater sensitivity to longer-term contingencies compared with abstinence.

DESIGN

Cross-sectional naturalistic field study.

SETTING

Southern United States.

PARTICIPANTS

Problem drinkers, recently resolved without treatment [n = 191 (76.44% male), mean age = 50.09 years] recruited using media advertisements.

MEASUREMENTS

Drinking practices, dependence levels and alcohol-related problems prior to stopping problem drinking were assessed during structured field interviews. Measures included the Zimbardo Time Perspective Inventory; BE analogue choice tasks [delay discounting (DD), melioration-maximization (MM), alcohol purchase task (APT)]; and the Alcohol-Savings Discretionary Expenditure (ASDE) index, derived from real spending on alcohol and voluntary savings during the year before problem cessation.

FINDINGS

Measures of demand based on real (ASDE) and hypothetical (APT) spending on alcohol were associated with problem severity (Ps < 0.05), but DD, MM and TP measures were not. More balanced pre-resolution spending on alcohol versus saving for the future distinguished low-risk drinking from abstinent resolutions (ASDE odds ratio =5.59; P < 0.001). BE measures did not share common variance.

CONCLUSIONS

Two behavioral assessment tools that measure spending on alcohol, the Alcohol Purchase Task and the Alcohol-Savings Discretionary Expenditure index, appear to be reliable in assessing the severity of drinking problems. The ASDE index also may aid choices between low-risk and abstinent drinking goals.

Behavioral sensitization of the reinforcing value of food: What food and drugs have in common

Sensitization is a basic property of the nervous system whereby repeated exposure to a stimulus results in an increase in responding to that stimulus. This increase in responding contributes to difficulty with treatment of drug abuse, as stimuli associated with substance use become signals or triggers for drug craving and relapse. Our work over the past decade has applied the theoretical framework of incentive sensitization to overeating. We have shown, in several studies, that lean adults do not commonly demonstrate behavioral sensitization after repeated exposure to snack food, but a subset of obese adults reliably does. This review will discuss this change in behavioral response to repeated consumption of snack food in obese individuals and apply the theoretical framework of incentive sensitization to drugs of abuse to high fat/high sugar snack foods. We will also show data that suggest that behavioral sensitization to repeated administration of snack food is predictive of weight gain, which may enhance its utility as a diagnostic tool for identifying at-risk individuals for obesity. Finally, we will discuss the future directions of this line of research, including studying the phenomenon in children and adolescents and determining if similar principles can be used to increase motivation to eat healthier food. A combination of reductions in unhealthy food intake and increases and healthy food intake is necessary to reduce obesity rates and improve health.

The substitutability of cigarettes and food: A behavioral economic comparison in normal weight and overweight or obese smokers

Obesity and cigarette smoking contribute to a multitude of preventable deaths in the United States and eating and smoking behavior may influence each other. The field of behavioral economics integrates principles from psychology and economics and permits systematic examination of how commodities interrelate with one another. Using this framework, the current study evaluated the effects of rising food and cigarette prices on consumption to investigate their substitutability and their relationship to BMI and associated variables. Behavioral economics categorizes commodities as substitutable when the consumption of one increases as a function of a price increase in the other. Smokers (N = 86) completed a 2-part hypothetical task in which money was allocated to purchase cigarettes and fast-food-style reinforcers (e.g., hamburgers, ice cream) at various prices. Results indicated that food and cigarettes were not substitutes for one another (cross-price elasticity coefficients < .20). Food purchases were independent of cigarette price, whereas cigarette purchases decreased as food price rose. Cross-price elasticity coefficients were significantly associated with confidence in one's ability to control weight without smoking (rs = -.23 and .29), but not BMI (rs = .04 and .04) or postcessation weight concerns (rs = -.05 and .12). Perceived ability to manage weight without cigarettes may influence who substitutes food for cigarettes when quitting. In addition, given observed decreases in purchases of both commodities as food prices increased, these findings imply that greater taxation of fast-food-style reinforcers could potentially reduce consumption of these foods and also cigarettes among smokers. (PsycINFO Database Record

Study design for a randomized controlled trial to increase the relative reinforcing value of vegetable consumption using incentive sensitization among obese and overweight people

In this manuscript, we present the protocol for a study that applies incentive sensitization theory to improve vegetable intake in overweight and obese adults. This 8-week, randomized, controlled, community-based feeding study with an 8-week follow-up seeks to use repeated exposure to amounts of vegetables recommended by federal guidance to increase the primary outcome of the relative reinforcing value of vegetables compared to a snack food. A community-based design is used to give participants autonomy in choosing their method of exposure. Secondary outcomes include: 1) Determine potential moderators of incentive sensitization of vegetables, including genetic polymorphisms associated with food reinforcement and obesity, 6-n-propylthiouracil tasting status, and delay discounting. 2) Determine whether adding vegetables to the diet results in participants substituting low-energy-dense vegetables for energy-dense foods or whether energy-dense food consumption is independent of vegetable consumption. 3) Determine whether reductions in adiposity are associated with substitution of vegetables in the diet. 4) Determine if markers of bone turnover change. 5) Assess changes in self-reported secondary outcomes measured by questionnaire such as self-efficacy to eat vegetables. The results of this study will provide information about the drivers of individual choice to consume recommended amounts of vegetables. The understanding gained will help increase the effectiveness and sustainability of behavior-based interventions focused on improving vegetable intake. This information may also be used to assist in setting dietary guidance targets for the amounts and types of vegetables Americans can, and should, consume.

Automating Scoring of Delay Discounting for the 21- and 27-Item Monetary Choice Questionnaires

Delay discounting describes the process wherein rewards lose value as a function of their delayed receipt; how quickly rewards lose value is termed the rate of delay discounting. Rates of delay discounting are robust predictors of much behavior of societal importance. One efficient approach to obtaining a human subject's rate of delay discounting is via the 21- and 27-item Monetary Choice Questionnaires, brief dichotomous choice tasks that assess preference between small immediate and larger delayed monetary outcomes. Unfortunately, the scoring procedures for the Monetary Choice Questionnaires are rather complex, which may serve as a barrier to their use. This report details a freely available Excel-based spreadsheet tool that automatically scores Monetary Choice Questionnaire response sets, using both traditional and contemporary/advanced approaches. An overview of the Monetary Choice Questionnaire and its scoring algorithm is provided. We conclude with general considerations for using the spreadsheet tool.

Pregnancy eating attributes study (PEAS): a cohort study examining behavioral and environmental influences on diet and weight change in pregnancy and postpartum

BACKGROUND

The rising prevalence of maternal overweight/obesity and excessive gestational weight gain poses a serious public health concern due to the contribution of these factors to increased risk of negative health outcomes for both mother and child. Scant intervention research has indicated moderate short-term improvement in maternal diet and gestational weight gain, with little evidence of long-term behavior change, in parallel with findings from interventions outside of pregnancy. Recent laboratory-based findings from neuroscience implicate aberrant reward processing of food at the brain level ("food reward sensitivity," the between-individual variation in the response to food stimuli) as a contributor to eating beyond energy needs. However, scant research has examined the influence of these processes on weight change in population-based settings, and the relevance of these processes to pregnancy-related weight change has not been explored. The purpose of the Pregnancy Eating Attributes Study (PEAS) is to examine the role of food reward sensitivity in maternal diet and weight change during pregnancy and postpartum. The study examines the interplay of food reward sensitivity with behavioral control, home food environment, and related aspects of eating behavior in the context of weight-related biomedical, psychosocial, genetic and behavioral factors including physical activity, stress, sleep and depression.

METHODS

Women of varying baseline weight status (n = 450) are enrolled early in pregnancy and followed, along with their infants, until 1 year postpartum. Assessments occur during each trimester of pregnancy, and postpartum at approximately 2 months, 6 months, 9 months and 12 months. Maternal food reward, self-control, home food environment, eating behaviors, dietary intake, health behaviors, and anthropometrics are assessed along with maternal and infant clinical and biological data, infant anthropometrics, and feeding practices. Primary exposures of interest include food reward sensitivity, behavioral control, and home food environment. Primary outcomes include gestational weight gain, postpartum weight retention and maternal diet quality.

DISCUSSION

With increasing evidence suggesting the relevance of food reward sensitivity for understanding eating behavior, PEAS aims to advance understanding of the determinants of eating behavior during pregnancy, informing future interventions for improving maternal diet and weight change, and leading to improved maternal and child health and weight trajectories.

TRIAL REGISTRATION

Clinicaltrials.gov, NCT02217462. Date of registration: August 13, 2014.

Reinforcer magnitude affects delay discounting and influences effects of d-amphetamine in rats

Impulsive choice in humans can be altered by changing reinforcer magnitude; however, this effect has not been found in rats. Current levels of impulsive choice can also influence effects of d-amphetamine. This study used a within-subject assessment to determine if impulsive choice is sensitive to changes in reinforcer magnitude, and whether effects of d-amphetamine are related to current levels of impulsive choice. A discounting procedure in which choice was for a smaller reinforcer available immediately or a larger reinforcer available after a delay that increased within session was used. Reinforcer magnitude was manipulated between conditions and impulsive choice was quantified using area under the curve (AUC). In the Smaller-Magnitude (SM) Condition, choice was between one food pellet and three food pellets. In the Larger-Magnitude (LM) Condition, choice was between two food pellets and six food pellets. Impulsive choice was greater in the SM Condition compared to the LM Condition. Further, effects of d-amphetamine (0.1-1.8mg/kg) were related to differences in impulsive choice. d-Amphetamine increased impulsive choice in the LM Condition, but had no effect on impulsive choice in the SM Condition. Overall, these results show that impulsive choice in rats is sensitive to changes in reinforcer magnitude, and that effects of d-amphetamine are influenced by current levels of impulsive choice.

Randomized controlled trial of a 12-month computerized mindfulness-based intervention for obese patients with binge eating disorder: The MindOb study protocol

BACKGROUND

Mindfulness-based interventions for healthy behaviors such as exercise and dietary modifications have aroused growing interest. This study aims to test the effectiveness of a mindfulness-based intervention for the reduction of impulsive eating and the improvement of motivation to exercise among obese individuals.

METHODS

One-hundred and twenty obese outpatients, aged 18 to 65years, diagnosed with a binge eating disorder, will be randomly assigned to one of the three following groups: mindfulness practice, sham meditation, or treatment as usual control. The tested intervention consists of a 1-year computerized mindfulness-based program. Mindfulness sessions are audio recordings that the patients are asked to listen to, 10min every day. Self-reported questionnaires measuring impulsive eating, motivation to exercise, physical activity level, mood, and mindfulness skills are filled in at baseline, 1, 6, and 12months. Physical activity, calories consumption, and biomarkers are measured with more objective measurement tools at baseline, 6months and 12months.

CONCLUSION

Mindfulness, as both a de-automation element and as a moderator of motivation to exercise, can lead to the reduction of impulsive eating and also to an increase in levels of physical activity. These effects could cause weight loss in obese patients suffering from binge eating disorder.

TRIAL REGISTRATION

clinicaltrials.gov: NCT02571387.

Healthy eating decisions require efficient dietary self-control in children: A mouse-tracking food decision study

Learning how to make healthy eating decisions, (i.e., resisting unhealthy foods and consuming healthy foods), enhances physical development and reduces health risks in children. Although healthy eating decisions are known to be challenging for children, the mechanisms of children's food choice processes are not fully understood. The present study recorded mouse movement trajectories while eighteen children aged 8-13 years were choosing between eating and rejecting foods. Children were inclined to choose to eat rather than to reject foods, and preferred unhealthy foods over healthy foods, implying that rejecting unhealthy foods could be a demanding choice. When children rejected unhealthy foods, mouse trajectories were characterized by large curvature toward an eating choice in the beginning, late decision shifting time toward a rejecting choice, and slowed response times. These results suggested that children exercised greater cognitive efforts with longer decision times to resist unhealthy foods, providing evidence that children require dietary self-control to make healthy eating-decisions by resisting the temptation of unhealthy foods. Developmentally, older children attempted to exercise greater cognitive efforts for consuming healthy foods than younger children, suggesting that development of dietary self-control contributes to healthy eating-decisions. The study also documents that healthy weight children with higher BMIs were more likely to choose to reject healthy foods. Overall, findings have important implications for how children make healthy eating choices and the role of dietary self-control in eating decisions.

Errors as a Means of Reducing Impulsive Food Choice

Nowadays, the increasing incidence of eating disorders due to poor self-control has given rise to increased obesity and other chronic weight problems, and ultimately, to reduced life expectancy. The capacity to refrain from automatic responses is usually high in situations in which making errors is highly likely. The protocol described here aims at reducing imprudent preference in women during hypothetical intertemporal choices about appetitive food by associating it with errors. First, participants undergo an error task where two different edible stimuli are associated with two different error likelihoods (high and low). Second, they make intertemporal choices about the two edible stimuli, separately. As a result, this method decreases the discount rate for future amounts of the edible reward that cued higher error likelihood, selectively. This effect is under the influence of the self-reported hunger level. The present protocol demonstrates that errors, well known as motivationally salient events, can induce the recruitment of cognitive control, thus being ultimately useful in reducing impatient choices for edible commodities.

The reinforcing value of palatable snack foods and its relationship to subtypes of behavioural and self-report impulsivity

Data collected over the last decade has begun to implicate behavioural impulsivity in overeating behaviour. However, recent work has suggested that the reinforcing value of food may be associated with impulsive choice (a sub-type of impulsivity), but to date no study has examined how the reinforcing value of food relates to other aspects of impulsivity. To examine these inter-relationships, 80 women completed measures of eating (a snack intake test and the Three-Factor Eating Questionnaire and then in a separate test session an inhibitory control task, a delay discounting task, a reflection impulsivity task, and a measure of the reinforcing value of their chosen snack foods. Participants also completed the Behavioural Inhibition System/Behavioural Activation System (BIS/BAS) questionnaire to examine self-report and behavioural parallels between measures. In regression models, only Behavioural Inhibition System subscales of the BIS/BAS predicted increased responding on the reinforcing value of food task. The reinforcing value of food task predicted and trended to predict calorie and grams intake of snack foods in regression models, supporting RRV as a predictive measure of short-term snack intake. Likewise, impulsive choice and inhibitory control was not related to eating measures. Methodological implications are discussed.

Reduced reward-driven eating accounts for the impact of a mindfulness-based diet and exercise intervention on weight loss: Data from the SHINE randomized controlled trial

Many individuals with obesity report over eating despite intentions to maintain or lose weight. Two barriers to long-term weight loss are reward-driven eating, which is characterized by a lack of control over eating, a preoccupation with food, and a lack of satiety; and psychological stress. Mindfulness training may address these barriers by promoting awareness of hunger and satiety cues, self-regulatory control, and stress reduction. We examined these two barriers as potential mediators of weight loss in the Supporting Health by Integrating Nutrition and Exercise (SHINE) randomized controlled trial, which compared the effects of a 5.5-month diet and exercise intervention with or without mindfulness training on weight loss among adults with obesity. Intention-to-treat multiple mediation models tested whether post-intervention reward-driven eating and psychological stress mediated the impact of intervention arm on weight loss at 12- and 18-months post-baseline among 194 adults with obesity (BMI: 30-45). Mindfulness (relative to control) participants had significant reductions in reward-driven eating at 6 months (post-intervention), which, in turn, predicted weight loss at 12 months. Post-intervention reward-driven eating mediated 47.1% of the total intervention arm effect on weight loss at 12 months [β = -0.06, SE(β) = 0.03, p = .030, 95% CI (-0.12, -0.01)]. This mediated effect was reduced when predicting weight loss at 18 months (p = .396), accounting for 23.0% of the total intervention effect, despite similar weight loss at 12 months. Psychological stress did not mediate the effect of intervention arm on weight loss at 12 or 18 months. In conclusion, reducing reward-driven eating, which can be achieved using a diet and exercise intervention that includes mindfulness training, may promote weight loss (clinicaltrials.gov registration: NCT00960414).

The Biggest Loser Thinks Long-Term: Recency as a Predictor of Success in Weight Management

Only a minority of participants in behavioral weight management lose weight significantly. The ability to predict who is likely to benefit from weight management can improve the efficiency of obesity treatment. Identifying predictors of weight loss can also reveal potential ways to improve existing treatments. We propose a neuro-psychological model that is focused on recency: the reliance on recent information at the expense of time-distant information. Forty-four weight-management patients completed a decision-making task and their recency level was estimated by a mathematical model. Impulsivity and risk-taking were also measured for comparison. Weight loss was measured in the end of the 16-week intervention. Consistent with our hypothesis, successful dieters (n = 12) had lower recency scores than unsuccessful ones (n = 32; p = 0.006). Successful and unsuccessful dieters were similar in their demographics, intelligence, risk taking, impulsivity, and delay of gratification. We conclude that dieters who process time-distant information in their decision making are more likely to lose weight than those who are high in recency. We argue that having low recency facilitates future-oriented thinking, and thereby contributes to behavior change treatment adherence. Our findings underline the importance of choosing the right treatment for every individual, and outline a way to improve weight-management processes for more patients.

A Cognitive Profile of Obesity and Its Translation into New Interventions

Change your lifestyle: decrease your energy intake and increase your energy expenditure, is what obesity experts tell people who need to lose weight. Though the advice might be correct, it appears to be extremely difficult to change one’s lifestyle. Unhealthy habits usually are ingrained and hard to change, especially for people with an “obese cognitive profile.” Knowledge of the cognitive mechanisms that maintain unhealthy eating habits is necessary for the development of interventions that can change behavior effectively. This paper discusses some cognitive processes that might maintain unhealthy eating habits and make healthier eating difficult, like increased food cue reactivity, weak executive skills and attention bias. An effort is also done to translate these basic scientific findings into new interventions which aim to tackle the sabotaging cognitive processes. Preliminary studies into the effectiveness of these interventions, if available, are presented.

The Effects of Weight Perception on Adolescents' Weight-Loss Intentions and Behaviors: Evidence from the Youth Risk Behavior Surveillance Survey

The objective of this study was to examine the correlation between self-perception of being overweight and weight loss intentions, eating and exercise behaviors, as well as extreme weight-loss strategies for U.S. adolescents. This study uses 50,241 observations from the Youth Risk Behavior Surveillance Survey (YRBSS) 2001-2009, which were nationally representative sample of 9th- through 12th-grade students in both public and private schools in the US. This study finds that, irrespective of the weight status base on self-reported weight and height, adolescents who perceive themselves as overweight have a stronger intention to lose weight, but do not develop better eating and exercise habits, compared with their counterparts of same gender and reported weight status. Normal-weight adolescents, if they perceive themselves as overweight, are more likely to engage in health-compromising weight-loss methods. This study shows that it is critical to transform weight-loss intentions into actual behaviors among overweight/obese adolescents and improve the efficacy of behavioral interventions against childhood obesity. It also highlights the need of establishing a correct perception of body weight among normal weight adolescents to curb extreme weight-loss methods.

Managing temptation in obesity treatment: A neurobehavioral model of intervention strategies

Weight loss outcomes in lifestyle interventions for obesity are primarily a function of sustained adherence to a reduced-energy diet, and most lapses in diet adherence are precipitated by temptation from palatable food. The high nonresponse and relapse rates of lifestyle interventions suggest that current temptation management approaches may be insufficient for most participants. In this conceptual review, we discuss three neurobehavioral processes (attentional bias, temporal discounting, and the cold-hot empathy gap) that emerge during temptation and contribute to lapses in diet adherence. Characterizing the neurobehavioral profile of temptation highlights an important distinction between temptation resistance strategies aimed at overcoming temptation while it is experienced, and temptation prevention strategies that seek to avoid or minimize exposure to tempting stimuli. Many temptation resistance and temptation prevention strategies heavily rely on executive functions mediated by prefrontal systems that are prone to disruption by common occurrences such as stress, insufficient sleep, and even exposure to tempting stimuli. In contrast, commitment strategies are a set of devices that enable individuals to manage temptation by constraining their future choices, without placing heavy demands on executive functions. These concepts are synthesized in a conceptual model that categorizes temptation management approaches based on their intended effects on reward processing and degree of reliance on executive functions. We conclude by discussing the implications of our model for strengthening temptation management approaches in future lifestyle interventions, tailoring these approaches based on key individual difference variables, and suggesting high-priority topics for future research.

Incidental rewarding cues influence economic decisions in people with obesity

Recent research suggests that obesity is linked to prominent alterations in learning and decision-making. This general difference may also underlie the preference for immediately consumable, highly palatable but unhealthy and high-calorie foods. Such poor food-related inter-temporal decision-making can explain weight gain; however, it is not yet clear whether this deficit can be generalized to other domains of inter-temporal decision-making, for example financial decisions. Further, little is known about the stability of decision-making behavior in obesity, especially in the presence of rewarding cues. To answer these questions, obese and lean participants (n = 52) completed two sessions of a novel priming paradigm including a computerized monetary delay discounting task. In the first session, general differences between groups in financial delay discounting were measured. In the second session, we tested the general stability of discount rates. Additionally, participants were primed by affective visual cues of different contextual categories before making financial decisions. We found that the obese group showed stronger discounting of future monetary rewards than the lean group, but groups did not differ in their general stability between sessions nor in their sensitivity toward changes in reward magnitude. In the obese group, a fast decrease of subjective value over time was directly related to a higher tendency for opportunistic eating. Obese in contrast to lean people were primed by the affective cues, showing a sex-specific pattern of priming direction. Our findings demonstrate that environments rich of cues, aiming at inducing unhealthy consumer decisions, can be highly detrimental for obese people. It also underscores that obesity is not merely a medical condition but has a strong cognitive component, meaning that current dietary and medical treatment strategies may fall too short.

Preschool-Adapted Liking Survey (PALS): A Brief and Valid Method To Assess Dietary Quality of Preschoolers

BACKGROUND

Feasible, valid, and reliable tools are needed to assess dietary quality among preschoolers. We aimed to test construct-/criterion-related validity and reliability of a dietary quality index generated from a liking survey and novel dietary patterns for characterizing food hedonism and parental feeding practices.

METHODS

Participants included 416 economically disadvantaged, diverse preschoolers (41% overweight/obese) from educational centers and their parents. Parents completed liking and frequency surveys; the liking survey took half as long to complete. Preschoolers' skin carotenoid status (measured by Resonance Raman spectroscopy) and BMI percentile (measured weight/height) were assessed. The Healthy Eating Preference Index (HEPI) was constructed from weighted averages of liking scores for food groups and healthy variety score and Healthy Eating Index 2010 (HEI) from nutrient analysis of the frequency survey.

RESULTS

The HEPI was normally distributed and showed construct validity and adequate internal reliability. In hierarchical regression analyses, the HEPI explained carotenoid status and adiposity as alternative or value-added predictors to HEI, supporting criterion-related validity of HEPI. Parental reporting of children's liking of high-fat/sweet/salty foods in excess of pleasurable activities (food hedonism) predicted heavier preschoolers, as did discord between HEI and HEPI (potential parental pressure toward healthy eating). HEPI alone or with HEI explained variability in carotenoid status and adiposity in path models with adequate to good fits.

CONCLUSIONS

With simple collection and processing, the liking survey can generate a valid/reliable dietary quality index in child care settings to identify preschoolers at risk for lower nutritional status. Using liking and frequency-based screeners could improve understanding of parental feeding behaviors and precision of predicting nutritional status.

Cued to Act on Impulse: More Impulsive Choice and Risky Decision Making by Women Susceptible to Overeating after Exposure to Food Stimuli

There is increasing evidence that individual differences in tendency to overeat relate to impulsivity, possibly by increasing reactivity to food-related cues in the environment. This study tested whether acute exposure to food cues enhanced impulsive and risky responses in women classified on tendency to overeat, indexed by scores on the three factor eating questionnaire disinhibition (TFEQ-D), restraint (TFEQ-R) and hunger scales. Ninety six healthy women completed two measures of impulsive responding (delayed discounting, DDT and a Go No-Go, GNG, task) and a measure of risky decision making (the balloon analogue risk task, BART) as well as questionnaire measures of impulsive behaviour either after looking at a series of pictures of food or visually matched controls. Impulsivity (DDT) and risk-taking (BART) were both positively associated with TFEQ-D scores, but in both cases this effect was exacerbated by prior exposure to food cues. No effects of restraint were found. TFEQ-D scores were also related to more commission errors on the GNG, while restrained women were slower on the GNG, but neither effect was modified by cue exposure. Overall these data suggest that exposure to food cues act to enhance general impulsive responding in women at risk of overeating and tentatively suggest an important interaction between tendency for impulsive decision making and food cues that may help explain a key underlying risk factor for overeating.

Impulsive delayed reward discounting as a genetically-influenced target for drug abuse prevention: a critical evaluation

This review evaluates the viability of delayed reward discounting (DRD), an index of how much an individual devalues a future reward based on its delay in time, for genetically-informed drug abuse prevention. A review of the literature suggests that impulsive DRD is robustly associated with drug addiction and meets most of the criteria for being an endophenotype, albeit with mixed findings for specific molecular genetic influences. Several modes of experimental manipulation have been demonstrated to reduce DRD acutely. These include behavioral strategies, such as mindfulness, reward bundling, and episodic future thinking; pharmacological interventions, including noradrenergic agonists, adrenergic agonists, and multiple monoamine agonists; and neuromodulatory interventions, such as transcranial magnetic stimulation and transcranial direct current stimulation. However, the generalization of these interventions to positive clinical outcomes remains unclear and no studies to date have examined interventions on DRD in the context of prevention. Collectively, these findings suggest it would be premature to target DRD for genetically-informed prevention. Indeed, given the evidence of environmental contributions to impulsive DRD, whether genetically-informed secondary prevention would ever be warranted is debatable. Progress in identifying polymorphisms associated with DRD profiles could further clarify the underlying biological systems for pharmacological and neuromodulatory interventions, and, as a qualitatively different risk factor from existing prevention programs, impulsive DRD is worthy of investigation at a more general level as a novel and promising drug abuse prevention target.

The genetics of impulsivity: evidence for the heritability of delay discounting

BACKGROUND

Delay discounting (DD), a decline in the subjective value of reward with increasing delay until its receipt, is an established behavioral model of impulsive choice, a key component of a broader impulsivity construct. Greater DD, i.e., a tendency to choose smaller immediate over larger delayed rewards, has been implicated as a potential intermediate phenotype (endophenotype) for addictive disorders and comorbid externalizing psychopathology, particularly in adolescence. However, genetic and environmental origins of DD remain unclear. Accordingly, the goal of the present study was to assess heritability of DD, an important aspect of its utility as an endophenotype.

METHODS

A commonly used computerized procedure involving choice between varying amounts of money available immediately and a standard amount of $100 presented at variable delays was administered to a population-based sample of twins aged 16 and 18 (n = 560, including 134 monozygotic and 142 dizygotic pairs). DD was quantified using area under the discounting curve and the k coefficient estimated by fitting a hyperbolic model to individual data. Heritability was assessed using linear structural equation modeling of twin data.

RESULTS

The genetic analysis revealed significant heritability of both DD measures (area under the discounting curve: 46% and 62%; k: 35% and 55% at age 16 and 18, respectively).

CONCLUSIONS

The present study provides evidence for heritability of both model-based and model-free DD measures and suggests that DD is a promising intermediate phenotype for genetic dissection of impulsivity and externalizing spectrum disorders.

A comparison of delay discounting in adolescents and adults in treatment for cannabis use disorders

Delay discounting is associated with problematic substance use and poorer treatment outcomes in adolescents and adults with substance use disorders. Although some research has addressed delay discounting among individuals with cannabis use disorders (CUDs), results have been equivocal, and no study has examined whether discounting rates differ between adolescent and adult cannabis users. The aim of this study was to compare discounting rates between adolescents and adults in treatment for CUD to determine whether discounting at intake or changes in discounting across treatment differed between age groups. Participants were 165 adolescents and 104 adults enrolled in treatment for CUD. Participants completed a delay discounting task at intake and end of treatment for 2 commodities (money and cannabis) at 2 different magnitudes ($100 and $1,000). Repeated measures mixed models examined differences in discounting rates by commodity and magnitude across age groups at intake and changes in discounting across treatment. At intake, adolescents discounted money more than adults whereas adults showed greater discounting at $100 magnitude than $1,000. In addition, adults had greater decreases in discounting of cannabis over the course of treatment. Overall, adolescents appeared less sensitive to changes in magnitude of rewards, discounted money at higher rates, and showed less improvement in discounting over the course of treatment compared to adults. Comparing delay discounting in adolescents and adults with CUD can contribute to a better understanding of how development influences the effect of discounting on substance use to better inform treatment for substance use disorders.

Does impulsiveness moderate response to financial incentives for smoking cessation among pregnant and newly postpartum women?

We examined whether impulsiveness moderates response to financial incentives for cessation among pregnant smokers. Participants were randomized to receive financial incentives delivered contingent on smoking abstinence or to a control condition wherein incentives were delivered independent of smoking status. The study was conducted in two steps: First, we examined associations between baseline impulsiveness and abstinence at late pregnancy and 24-weeks-postpartum as part of a planned prospective study of this topic using data from a recently completed, randomized controlled clinical trial (N = 118). Next, to increase statistical power, we conducted a second analysis collapsing results across that recent trial and two prior trials involving the same study conditions (N = 236). Impulsivity was assessed using a delay discounting (DD) of hypothetical monetary rewards task in all three trials and Barratt Impulsiveness Scale (BIS) in the most recent trial. Neither DD nor BIS predicted smoking status in the single or combined trials. Receiving abstinence-contingent incentives, lower baseline smoking rate, and a history of quit attempts prepregnancy predicted greater odds of antepartum abstinence across the single and combined trials. No variable predicted postpartum abstinence across the single and combined trials, although a history of antepartum quit attempts and receiving abstinence-contingent incentives predicted in the single and combined trials, respectively. Overall, this study provides no evidence that impulsiveness as assessed by DD or BIS moderates response to this treatment approach while underscoring a substantial association of smoking rate and prior quit attempts with abstinence across the contingent incentives and control treatment conditions.

Eat now or later: self-control as an overlapping cognitive mechanism of depression and obesity

While overlapping neurobiological mechanisms are known, relatively little is known about how “self-control” and cognitive affective processing of rewards may also influence the bi-directional risk between obesity and depression. The objective of this study was to identify the extent to which “self-control,” measured using a delay discounting task is co-related to BMI and Depression diagnostic thresholds. A within-subjects counterbalanced design was used in which 92 participants (Mean±SD: BMI = 27.9±3.5, HAMD = 14.7±7.7) completed a series of clinical diagnostic, survey, and demographic questionnaires in a behavioral health laboratory setting. For the delay discounting task, participants chose between one large delayed reward and one successively smaller immediate reward for four food types (dessert, fried food, fruit, and vegetable). Results showed that delay discounting scores were predictive of BMI and depression with lower delay discounting scores associated with higher BMI and HAMD for the dessert (HAMD scores (β = -.197, p = .013), BMI (β = -.239, p < .001)) and fried food (HAMD scores (β = -.328, p = .001), BMI (β = -.166, p = .027)). Clinical significance was further evident when HAMD and BMI scores were converted to diagnostic thresholds. Only depression and/or atypical depressive symptoms were related to delay discounting scores with the fruit and vegetable. Thus, reduced cognitive affective self-control for impulsive food choices—particularly for “comfort foods” high in fat and sugar—appears to be a shared cognitive mechanism for both conditions perhaps contributing to the high prevalence of co-morbid mood disorders and weight gain.

Prospect theory and body mass: characterizing psychological parameters for weight-related risk attitudes and weight-gain aversion

We developed a novel decision-making paradigm that allows us to apply prospect theory in behavioral economics to body mass. 67 healthy young adults completed self-report measures and two decision-making tasks for weight-loss, as well as for monetary rewards. We estimated risk-related preference and loss aversion parameters for each individual, separately for weight-loss and monetary rewards choice data. Risk-seeking tendency for weight-loss was positively correlated with body mass index in individuals who desired to lose body weight, whereas the risk-seeking for momentary rewards was not. Risk-seeking for weight-loss was correlated to excessive body shape preoccupations, while aversion to weight-gain was correlated with self-reports of behavioral involvement for successful weight-loss. We demonstrated that prospect theory can be useful in explaining the decision-making process related to body mass. Applying prospect theory is expected to advance our understanding of decision-making mechanisms in obesity, which might prove helpful for improving healthy choices.

Therapeutic Opportunities for Self-Control Repair in Addiction and Related Disorders: Change and the Limits of Change in Trans-Disease Processes

Contemporary neuro-economic approaches hypothesize that self-control failure results from drugs annexing normal learning mechanisms that produce pathological reward processing and distort decision-making as a result from the dysregulation of two valuation systems. An emphasis on processes shared across different diseases and disorders is at odds with the contemporary approach that assumes unique disease etiologies and treatments. Studying trans-disease processes can identify mechanisms that operate in multiple disease states and ascertain if factors that influence processes in one disease state may be applicable to all disease states. In this paper we review the dual model of self-control failure, the Competing Neurobehavioral Decision Systems approach, the relationship of delay discounting to the relative control of these two systems, and evidence that the executive system can be strengthened. Future research that could result in more potent interventions for executive system improvement and potential constraints on the repair of self-control failure are discussed.

Early life stress in fathers improves behavioural flexibility in their offspring

Traumatic experiences in childhood can alter behavioural responses and increase the risk for psychopathologies across life, not only in the exposed individuals but also in their progeny. In some conditions, such experiences can however be beneficial and facilitate the appraisal of adverse environments later in life. Here we expose newborn mice to unpredictable maternal separation combined with unpredictable maternal stress (MSUS) for 2 weeks and assess the impact on behaviour in the offspring when adult. We show that MSUS in male mice favours goal-directed behaviours and behavioural flexibility in the adult offspring. This effect is accompanied by epigenetic changes involving histone post-translational modifications at the mineralocorticoid receptor (MR) gene and decreased MR expression in the hippocampus. Mimicking these changes pharmacologically in vivo reproduces the behavioural phenotype. These findings highlight the beneficial impact that early adverse experiences can have in adulthood, and the implication of epigenetic modes of gene regulation.

Can't wait to lose weight? Characterizing temporal discounting parameters for weight-loss

Obesity is often related to steeper temporal discounting, that is, higher decision impulsivity for immediate rewards over delayed rewards. However, previous studies have measured temporal discounting parameters through monetary rewards. The aim of this study was to develop a temporal discounting measure based on weight-loss rewards, which may help to understand decision-making mechanisms more closely related to body weight regulation. After having their heights and weights measured, healthy young adults completed the Monetary Choice Questionnaire (MCQ), and an adapted version of the MCQ, with weight-loss as a reward. Participants also completed self-reports that measure obesity-related cognitive variables. For 42 participants who expressed a desire to lose weight, weight-loss rewards were discounted over time and had a positive correlation with temporal discounting for monetary rewards. Higher temporal discounting for weight loss rewards (i.e., preference for immediate weight loss) showed correlations with beliefs that obesity is under obese persons' control and largely due to lack of willpower, while temporal discounting parameters for monetary rewards did not. Taken together, our weight loss temporal discounting measure demonstrated both convergent and divergent validity, which can be utilized for future obesity research and interventions.

A Competing Neurobehavioral Decision Systems model of SES-related health and behavioral disparities

We propose that executive dysfunction is an important component relating to the socio-economic status gradient of select health behaviors. We review and find evidence supporting an SES gradient associated with (1) negative health behaviors (e.g., obesity, excessive use of alcohol, tobacco and other substances), and (2) executive dysfunction. Moreover, the evidence supports that stress and insufficient cognitive resources contribute to executive dysfunction and that executive dysfunction is evident among individuals who smoke cigarettes, are obese, abuse alcohol, and use illicit drugs. Collectively these data support the dual system model of cognitive control, referred to here as the Competing Neurobehavioral Decision Systems hypothesis. The implications of these relationships for intervention and social justice considerations are discussed.

Errors affect hypothetical intertemporal food choice in women

Growing evidence suggests that the ability to control behavior is enhanced in contexts in which errors are more frequent. Here we investigated whether pairing desirable food with errors could decrease impulsive choice during hypothetical temporal decisions about food. To this end, healthy women performed a Stop-signal task in which one food cue predicted high-error rate, and another food cue predicted low-error rate. Afterwards, we measured participants' intertemporal preferences during decisions between smaller-immediate and larger-delayed amounts of food. We expected reduced sensitivity to smaller-immediate amounts of food associated with high-error rate. Moreover, taking into account that deprivational states affect sensitivity for food, we controlled for participants' hunger. Results showed that pairing food with high-error likelihood decreased temporal discounting. This effect was modulated by hunger, indicating that, the lower the hunger level, the more participants showed reduced impulsive preference for the food previously associated with a high number of errors as compared with the other food. These findings reveal that errors, which are motivationally salient events that recruit cognitive control and drive avoidance learning against error-prone behavior, are effective in reducing impulsive choice for edible outcomes.

A behavioral economic analysis of changes in food-related and food-free reinforcement during weight loss treatment

OBJECTIVE

Behavioral economic theory predicts that reductions in consumption of highly valued commodities, such as drugs or palatable food items, are facilitated by increasing engagement in reinforcing substitutes. The current study prospectively examines changes in engagement in and enjoyment of food versus food-free activities during an 18-month behavioral weight loss intervention.

METHOD

Participants were 202 overweight/obese individuals who took part in an 18-month behavioral weight loss treatment and were randomly assigned to a traditional hypocaloric, low-fat diet condition or a traditional hypocaloric, low-fat diet plus a goal to limit variety in snack food consumption condition. At baseline and 6, 12, and 18 months, participants were weighed and completed a measure that assessed recent frequency of engagement in and enjoyment of a variety of both food and food-free activities.

RESULTS

Growth models revealed a statistically significant decrease in the relative percentage of food-related reinforcement (vs. food-free) over time (reinforcement ratio, or RR), with the greatest reduction during the first 6 months of treatment. Food-related reinforcement decreased over time, and food-free reinforcement increased. Additionally, the RR change predicted change in body mass index (BMI) from 0 to 6 months and 0 to 18 months, such that greater changes in RR were associated with greater changes in BMI.

CONCLUSIONS

Findings suggest that behavioral weight loss treatment may promote a shift away from food-related reinforcement toward food-free reinforcement and that this change may predict BMI change. Future interventions may consider targeting increasing engagement in enjoyable food-free activities to help with long-term maintenance.

Clues to maintaining calorie restriction? Psychosocial profiles of successful long-term restrictors

To combat the obesity epidemic, interventions and treatments often recommend low-calorie dieting. Calorie restriction (CR) as a weight intervention, however, is often unsuccessful, as most people cannot sustain the behavior. Yet one small group has maintained extreme CR over years - members of the CR Society and followers of The CR Way. This study examined stable psychosocial characteristics of these individuals to identify traits that may promote success at long-term CR. In 65 participants, we measured diet, eating behaviors, and personality traits comparing calorie restrictors with two age-, gender-, ethnicity-, and education-matched comparison groups (normal weight and overweight/obese). We first tested whether the CR group restricted calories without indications of eating disorder pathology, and second, what crystallized psychosocial characteristics set them apart from their nonrestricting comparisons. Results indicated the CR group averaged 10 years of CR but scored lower than comparison groups on measures of disordered eating (p < .001) and psychopathology (p < .001). Particularly against overweight/obese participants, CR participants scored lower on neuroticism (p < .04) and hostility (p < .01), and were stronger in future time orientation (p < .05). Overall, CR profiles reflected high self-control and well being, except for having few close relationships. This study suggests a potential predisposition for successful long-term CR without disordered eating. Since modifying trait factors may be unrealistic, there may be psychosocial boundaries to the capacity for sustaining CR. Paralleling a movement toward personalized medicine, this study points toward a personalized behavioral medicine model in behavioral nutrition and treatment of overweight/obesity.

Food reinforcement and parental obesity predict future weight gain in non-obese adolescents

BACKGROUND

Food reinforcement, the extent to which people are willing to work to earn a preferred snack food, and parental obesity are risk factors for weight gain, but there is no research comparing the predictive effects of these factors for adolescent weight gain.

METHODS

130 non-obese adolescents (M age=15.2 ± 1.0; M BMI=20.7 ± 2.0; M zBMI=0.16 ± 0.64) at differential risk for weight gain based on parental obesity completed baseline food and money reinforcement tasks, and provided zBMI data over a 2-year follow-up.

RESULTS

The number of obese (BMI ≥ 30) parents (p=0.007) and high food reinforcement (p=0.046) were both significant independent predictors of greater zBMI increases, controlling for age, sex, parent education and minority status. Having no obese parents or being low or average in food reinforcement was associated with reductions in zBMI, but those high in food reinforcement showed larger zBMI increases (0.102) than having one obese parent (0.025) but less than having two obese parents (0.177).

DISCUSSION

Food reinforcement and parental obesity independently predict future weight gain among adolescents. It might be fruitful for obesity prevention programs to target both high risk groups.