Daily consumption of individual snack foods decreases their reinforcing value

The relationship among disordered eating behavior, power of food scale and sensitization of the reinforcing value of food

INTRODUCTION

Disordered eating behaviors are a current public health concern since their progression can lead to the development of a full criteria eating disorder. Sensitization to repeated intake of high energy density (HED) foods is associated with excess weight gain over time, but less is known about relationships with assessments of disordered eating. Thus, this study aims to understand how disordered eating behaviors refunlate to the influence of the food environment and sensitization.

METHOD

163 adolescents - 50 % female and 13.2 mean age - were followed for 24 months. Sensitization was assessed by comparing the relative reinforcing value (RRV) of HED food at baseline and after two weeks of daily intake; sensitization was defined as RRV of food after repeated intake. Study participants also completed the EDE-Q, and Power of Food Scale (PFS). We conducted multivariate general linear models to examine these associations.

RESULTS

Sensitization status and PFS scores at baseline were positively associated with EDE-Q subscale scores cross-sectionally, but not longitudinally, at baseline and 24 months. We found that sensitization to HED food and higher susceptibility to food cues relates to increased disordered eating behaviors and both at baseline and at 24-months.

DISCUSSION

These findings suggest that sensitization to repeated HED food intake and the food environment might be a risk factor for later engagement in disordered eating behaviors. Future studies should address the temporal relationships among these factors and the role that social norms around body weight and weight stigma may play in the development of these behaviors.

The Influence of Relative Reinforcing Value of Food, Sensitization, Energy Intake and Diet Quality on zBMI Change over Two Years in Adolescents: A Longitudinal Cohort Study

The relative reinforcing value (RRV) of food and sensitization are associated with zBMI and zBMI change over time, but the mechanisms underlying these relationships is unknown. The purpose of this study was to test the hypothesis that greater RRV and sensitization to HED food is associated with lower diet quality and greater energy intake at baseline and again at 24 months and that these relationships result in greater zBMI gain. The RRV of HED and LED food and dietary intake were measured at baseline and again after 24 months in a cohort of 202 boys and girls of 12-14 years old. The baseline RRV of HED food was associated with lower diet quality and lower energy intake at 24 months. zBMI gain was positively associated with the baseline energy intake but not baseline RRV of HED food or diet quality. However, diet quality moderated the relationship between baseline energy intake and zBMI change, with no difference in zBMI change as a function of energy intake when diet quality was high but significant and opposite relationships with energy intake when diet quality was low. This study suggests that high diet quality can reduce the negative impact of greater energy intake on zBMI change in adolescents.

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

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

Sensitization of the reinforcing value of high energy density foods is associated with increased zBMI gain in adolescents

Background/Objectives

Characterizing behavioral phenotypes that predict increased zBMI gain during adolescence could identify novel intervention targets and prevent the development of obesity. The purpose of this study was to determine if sensitization of the relative reinforcing value (RRV) of high (HED) or low energy density (LED) foods predicts adolescent weight gain trajectories. A secondary aim was to test the hypothesis that relationships between sensitization of the RRV of food and weight change are moderated by delay discounting (DD).

Subjects/Methods

We conducted a prospective, longitudinal cohort study in 201 boys and girls with an average zBMI of 0.4, who began the study between the ages of 12 and 14 years and completed the study 2 years later. Participants completed five laboratory visits where the RRV of HED and LED, and DD were assessed at a baseline (visits 1, 2, and 4) and then RRV was measured again after participants consumed a portion of the same HED and LED food for 2 weeks (visits 3 and 5; order counterbalanced). Increases (>1) in the RRV from baseline to post-daily intake were categorized as “sensitization” and decreases (≤1) were categorized as “satiation.” Participants returned to the laboratory for follow-up visits at 6, 15, and 24 months to have height and weight taken and to complete additional assessments.

Results

Sensitization to HED food was associated with a greater zBMI change over time (β = 0.0070; p = 0.035). There was no impact of sensitization to LED food or interaction between sensitization to HED and LED food on zBMI change and no moderation of DD on the relationship between HED sensitization and zBMI change (all p > 0.05).

Conclusion

Our prior work showed that sensitization to HED food is cross-sectionally associated with greater zBMI. This study extends this work by demonstrating that sensitization to HED food prospectively predicts increased zBMI gain over time in adolescents without obesity. Future studies should determine if sensitization can be modified or reduced through behavioral intervention.

Trial registration

Clinicaltrials.gov: NCT04027608.

Interactive influences of food, contexts and neurocognitive systems on addictive eating

Compulsive eating is a common symptom of different conditions, including obesity, binge eating disorder and bulimia. One hypothesis is that contemporary food products promote compulsive eating via addiction-like mechanisms. However, what is the addictive substance in food, and what is the phenotypic overlap between obesity / eating disorders and addictions are questions that remain unresolved. In this review, we applied a multilevel framework of addiction, which encompasses the 'drug' (certain foods), the person's mindset, and the context, to improve understanding of compulsive eating. Specifically, we reviewed evidence on the addictive properties of specific foods, the neurocognitive systems that control dietary choices, and their interaction with physical, emotional and social contexts. We focused on different target groups to illustrate distinct aspects of the proposed framework: the impact of food and contextual factors were examined across a continuum, with most studies conducted on healthy participants and subclinical populations, whereas the review of neurocognitive aspects focused on clinical groups in which the alterations linked to addictive and compulsive eating are particularly visible. The reviewed evidence suggest that macronutrient composition and level of processing are associated with the addictive properties of food; there are overlapping neuroadaptations in reward and decision-making circuits across compulsive eating conditions; and there are physical and social contexts that fuel compulsive eating by exploiting reward mechanisms and their interaction with emotions. We conclude that a biopsychosocial model that integrates food, neurobiology and context can provide a better understanding of compulsive eating manifestations in a transdiagnostic framework.

Fat and Carbohydrate Interact to Potentiate Food Reward in Healthy Weight but Not in Overweight or Obesity

Prior work suggests that actual, but not estimated, energy density drives the reinforcing value of food and that energy from fat and carbohydrate can interact to potentiate reward. Here we sought to replicate these findings in an American sample and to determine if the effects are influenced by body mass index (BMI). Thirty participants with healthy weight (HW; BMI 21.92 ± 1.77; M ± SD) and 30 participants with overweight/obesity (OW/OB; BMI 29.42 ± 4.44) rated pictures of common American snacks in 120-kcal portions for liking, familiarity, frequency of consumption, expected satiety, healthiness, energy content, energy density, and price. Participants then completed an auction task where they bid for the opportunity to consume each food. Snacks contained either primarily carbohydrate, primarily fat, or roughly equal portions of fat and carbohydrate (combo). Replicating prior work, we found that participants with HW bid the most for combo foods in linear mixed model analyses. This effect was not observed among individuals with OW/OB. Additionally, in contrast with previous reports, our linear regression analyses revealed a negative relationship between the actual energy density of the snacks and bid amount that was mediated by food price. Our findings support altered macronutrient reinforcement in obesity and highlight potential influences of the food environment on the regulation of food reward.

Having less and wanting more: an investigation of socioeconomic status and reinforcement pathology

BACKGROUND

In the United states obesity and socioeconomic status (SES), or one's standing in society based on income, education, and/or occupation, are strongly associated. The mechanisms for this relationship may include having high levels of motivation to get food (reinforcing value of food; RRV) and low levels of inhibitory control (delay discounting; DD) which, when combined, is referred to as reinforcement pathology (RP). We sought to examine the relationships among multiple measures of household SES, RP, and age-adjusted body mass index (zBMI) among adolescents.

METHODS

These data were collected as part of ongoing longitudinal study of risk factors for obesity in 244 adolescents. The adolescents and one parent/guardian had height and weight measured and completed surveys. The adolescents completed an adjusting amount DD task and a computer-based RRV task. Analyses consisted of correlations among measures of SES and RRV, DD, and BMI z-scores. In the case of significant associations, multiple regression models were created with theoretically informed covariates.

RESULTS

Household income, parent/guardian education, parent/guardian occupation, and food insecurity status were all related to one another. Among the adolescents, a significant portion of the variance in RRV was accounted for by household income after controlling for covariates. For DD, it was parent/guardian education that was most associated after controlling for covariates.

CONCLUSION

When low income and low parent/guardian education occur together, there may be an increased risk of RP. Separately, food insecurity was predictive of higher parent/guardian BMI. Future research should continue to explore the effects of low income and parent/guardian education on RP among youth by examining them over time.

Home consumption of two fortified balanced energy protein supplements by pregnant women in Burkina Faso

Balanced energy protein (BEP) supplementation for pregnant and lactating women in low‐ and middle‐income countries is a promising strategy to improve birth outcomes and child growth. The objective of this study was to assess and compare the acceptability of new formulations of two fortified BEP supplements, a lipid‐based peanut paste and a vanilla biscuit, among 80 pregnant women in rural Burkina Faso, prior to an efficacy trial. A 10‐week individually randomized cross‐over study was designed, in which women received a weekly supply of each supplement for 4 weeks, and a daily choice between the supplements in the last 2 weeks. Questionnaires to assess daily consumption and supplement acceptability (n = 80) and home observations (n = 20) were combined with focus group discussions (n = 6) and in‐depth interviews with women (n = 80) and stakeholders (n = 24). Results showed that the two supplements were well accepted. Quantitative findings indicated high compliance (>99.6%) and high overall appreciation (Likert score >6 out of 7) of both supplements. The assessment of preferred choice in Weeks 9 and 10 indicated a slight preference for the vanilla biscuit. Qualitative findings indicated that perceived health benefits, support from household members and educational messages from health professionals were important drivers for acceptance and compliance. Sharing was not often reported but was identified during interviews as a possible risk. We recommend that future studies use a combination of methods to identify appropriate food supplements and context‐specific factors that influence acceptability, compliance and subsequent impact of nutritious food supplements.

Teaching families to manage intake of candy in the home: Results from a feasibility study using multiphase optimization strategy (MOST)

BACKGROUND

Excess intake of desserts/sweets high in added sugars, such as candy, is linked with greater obesity risk. Parents often limit their childrens' intake of these sweet foods using controlling feeding practices, such as restriction; yet, restrictive feeding practices are counterproductive for childrens' self-regulation of energy intake.

OBJECTIVE

This study developed a family-based behavioural intervention that taught parents alternatives to restrictive feeding practices and encouraged children to consume candy in moderation.

METHODS

Using the multiphase optimization strategy (MOST), parent-child dyads (N = 37) were randomized into one of eight conditions that included a combination of intervention components delivered over 4 weeks: home supply, parent shared decision making, child mindfulness and child attention control strategies.

RESULTS

Retention rate at follow-up was high (95%). Among parents who received parent shared decision making, 86.4% reported the structured-based candy routine they set with their child was easy to follow. Most children reported child mindfulness (95%) and attention control (89.5%) strategies were easy to play. Children recalled 4.1 ± 1.8 of the six mindfulness strategies and 2.7 ± 1.6 of the five attention control strategies at follow-up. Eating in the absence of hunger tended to be lower for children who received parent shared decision making and child mindfulness components.

CONCLUSION

This intervention was feasible and well-implemented in the home environment. Findings will inform future, larger interventions designed to test similar strategies on childrens; eating behaviours and self-regulation.

Sensitization of the reinforcing value of food: a novel risk factor for overweight in adolescents

Background and Objectives

The relative reinforcing value (RRV) of food is associated with increased energy intake and obesity and increases in RRV of food after repeated intake (sensitization) are related cross-sectionally and prospectively to higher BMI in adults. We examined the factors, such as delay discounting (DD), associated with sensitization of RRV of high energy density (HED) and low energy density (LED) food and how sensitization relates to zBMI in adolescents. We hypothesized that sensitization to HED food would be positively associated with zBMI, that sensitization to LED food would be negatively associated with zBMI, that DD would be associated with HED sensitization, and that LED sensitization and DD would moderate the relationships between HED sensitization and zBMI.

Subjects and Methods

A population-based sample of 207 adolescents without obesity, aged 12 – 14 years was studied from June 2016 – March 2019. The RRV of LED and HED foods were measured before and after two weeks of daily consumption along with zBMI and other potential factors related to eating and weight, including dietary restraint, hunger, food liking, and delay discounting (DD). Hierarchical regression models were used to determine the associations between these factors and sensitization and zBMI. We also examined LED sensitization and DD as potential moderators of the relationship between sensitization and zBMI.

Results

As hypothesized, dietary restraint and sensitization to HED food were associated with greater zBMI. Contrary to our original hypotheses, DD was not associated with sensitization, there was no relationship between sensitization to LED food and zBMI and neither LED sensitization or DD moderated the relationship between HED sensitization and zBMI.

Conclusions

Sensitization to repeated intake of HED food was associated with higher zBMI in adolescents without obesity. Sensitization may be a novel behavioral phenotype that may relate to overweight in youth.

The relationships between eating disorder pathology and relative reinforcing value of food, delay discounting, and related constructs in adolescents

Food is a primary reinforcer that motivates behavior in the absence of learning or conditioning. Both the relative reinforcing value (RRV) of food and delay discounting are associated with weight status. While dietary restraint and disinhibition have been shown to influence the RRV of food, limited work has examined the relationships between eating disorder pathology and RRV of food and delay discounting. Therefore, the purpose of this study was to examine how eating disorder pathology predicts RRV of food, proportion of food consumed, delay discounting, reinforcement pathology (i.e., high motivation to eat and high delay discounting), and sensitization of high energy dense food (HED; i.e., increases in RRV of HED food after daily repeated exposure). Participants were 167 adolescents ages 12-14 without obesity participating in a longitudinal study examining predictors of weight change who completed a series of laboratory assessments assessing the RRV of food of HED food, delay discounting, reinforcement pathology, sensitization of HED food, and a questionnaire assessing eating disorder pathology. Eating disorder pathology was not related to the RRV of food or delay discounting, but did predict reinforcement pathology and the sensitization of HED food. When explored by weight status, these relationships were only observed for those with overweight. There were no other significant relationships for either adolescents with normal weight or overweight. Given that weight status appeared to moderate some of the relationships between eating disorder pathology and reinforcement-related constructs, future work should examine how reinforcement pathology and eating disorder pathology are related to changes in weight status over time.

Reinforcing Value of Caffeinated and Noncaffeinated Beverages After Acute Exposure in Children and Adolescents

Background: When caffeine is added to beverages, it increases beverage liking and the relative reinforcing value (RRV) of these beverages after repeated exposure. The purpose of this study was to test the hypothesis that a single acute exposure to caffeine increases liking and motivation to consume sugar-sweetened beverages (SSBs) relative to placebo. Methods: Participants were children ages 8-9 years (n = 36) and adolescents ages 15-17 years (n = 41) with an approximately equal number of boys and girls. A double-blind, placebo-controlled crossover study was conducted where participants sampled a SSB containing caffeine (1 and 2 mg/kg) on one visit and placebo (quinine 0.01 and 0.02 mg/kg) on a second visit day and then, on a third visit, played a computer game to earn points for the beverages and rated liking and taste sensations. They returned to the laboratory after a 1-week washout and had the alternate dose combination. Results: Acute exposure to the higher dose of caffeine increased the RRV of the SSB relative to placebo, but only when that dose was presented in the first week and only in female participants. The liking of the caffeine-containing SSB at the higher dose was lower than the placebo at all time points. Conclusions: These data suggest that a single exposure to a caffeinated SSB can impact its RRV and liking, but only under certain conditions and only in females. This supports previous work suggesting that caffeine can increase desire to consume SSB.

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.

Food reinforcement during infancy

The motivation to eat, as operationalized by measuring how hard someone will work for food, is cross-sectionally and prospectively related to obesity. Persons high in food reinforcement consume more calories, and energy intake mediates the relationship between food reinforcement and obesity. Research has shown avid sucking for milk in early infancy predicts later adiposity, and the relationship between food reinforcement and excess body weight has been observed in infants as young as 9months of age. New methodological developments in studying food reinforcement in infants and young children provide the first opportunity to study the origin of food reinforcement. This review seeks to provide background on the measurement of food reinforcement, and to present, for the first time, prenatal and postnatal predictors of infant food reinforcement. Lastly, potential mechanisms for an increasing trajectory of food reinforcement throughout development are proposed.

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.

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.

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.

Energy depletion by diet or aerobic exercise alone: impact of energy deficit modality on appetite parameters

BACKGROUND

Millions of Americans attempt to lose weight each year, and it is unclear whether the modality of acute, tightly controlled energy depletions can differently affect appetite parameters and olfaction.

OBJECTIVE

The objectives were to examine how the modality of an acute 3-d isocaloric 25% energy depletion by dieting alone or by aerobic exercise alone differently affects appetite and appetite-related hormones, ad libitum feeding, food reward (snack points), and olfaction.

DESIGN

Ten male participants with a mean ± SD age of 23.7 ± 5.1 y and an initial mean ± SD body weight of 83.2 ± 11.5 kg participated in this randomized crossover design. Baseline measurement [day 1 of the control condition (CON1)] was performed and repeated 3 d later [day 4 of the control condition (CON4)], after which randomization was applied to the order of the 2 experimental conditions: 25% daily needs energy deficits induced by diet only (DIET) and by exercise only (EX) and tested before [day 1 of DIET (DIET1) and day 1 of EX (EX1)] and after 3 d [day 4 of DIET (DIET4) and day 4 of EX (EX4)] of the intervention. Body weight, leptin and ghrelin concentrations, relative-reinforcing value of food, and olfaction were measured at days 1 and 4. Body composition (dual-energy X-ray absorptiometry), ad libitum energy intake (EI; buffet), and palatability (visual analog scale) were measured only at day 4.

RESULTS

Relative to CON4, EI (P= 0.001), palatability (P= 0.01), and odor threshold (P= 0.05) were higher at DIET4; relative to CON4, palatability (P= 0.03) was higher at EX4. Compared with EX4, EI was higher for DIET4 (P= 0.006). Relative to CON4, snack points earned were higher at DIET4 (P= 0.03) and EX4 (P= 0.001); more snack points were earned at EX4 relative to DIET4 (P= 0.001).

CONCLUSIONS

Compared with the control condition, DIET represented a greater acute challenge to appetite regulation than EX, as demonstrated by greater appetite and ad libitum EI. This study confirms that compared with depletions by exercise alone, acute caloric restriction results in rapid changes in appetite that result in compensatory eating, which may initially dissuade potential success in weight-loss efforts. This trial was registered at clinicaltrials.gov as NCT02653378.

Reducing variety enhances effectiveness of family-based treatment for pediatric obesity

Basic research has shown that increasing variety increases energy intake, and repeated consumption of the same food increases habituation to those foods and reduces consumption. Twenty-four families with overweight/obese 8-12 year-old children and overweight/obese parents were randomly assigned to 6months of usual family based treatment (FBT) or FBT plus reduced variety of high energy-dense foods (FBT+Variety). Intention to treat mixed model ANOVA showed between group differences in child percent overweight (FBT+Variety-15.4% vs. FBT-8.9%, p=0.017) and parent BMI (FBT+Variety-3.7kg/m(2) vs. FBT-2.3kg/m(2); p=0.017). Positive relationships were observed between child zBMI and parent BMI changes (r=0.51, p=0.018), and between reductions in food variety of high energy-dense foods and reductions in child zBMI (r=0.54, p=0.02) and parent BMI (r=0.45, p=0.08). These pilot data suggest that reducing the variety of high energy dense foods and repeating meals within the context of FBT resulted in improved child and parent weight changes at six months. This represents easy to implement changes that reduce choice and may reduce response burden on families. Reducing variety may be a complement to standard FBT that enhances weight loss. Long term studies are needed to assess maintenance of these changes.

Candy consumption patterns, effects on health, and behavioral strategies to promote moderation: summary report of a roundtable discussion

Nearly all Americans (97%) report eating candy at least once per year; yet, on a given day, only approximately one-fourth of the US population aged ≥2 y consumes candy. Among all Americans, candy contributes a relatively small proportion of calories, added sugars, and saturated fat to the total diet, and recent research suggests that current levels of candy consumption are not associated with risk of weight gain and cardiovascular disease in children and adults. Providing guidance for the consumption of candy in moderation requires an understanding of various behavioral health-related factors that influence candy consumption. A roundtable of behavioral nutrition experts, researchers, and nutrition educators met to discuss recent data on intakes of candy, health outcomes associated with usual candy intake, and the impact of behavioral strategies, including restriction, education, and environmental awareness, on modifying eating behaviors to achieve moderate intakes of candy. Restricting access to palatable foods, whether self-imposed or by parental control, may have potentially negative consequences. Techniques and insight into how to adopt "moderation" in candy consumption, from effective parental practices to environmental strategies that facilitate behavior change without a high degree of effort, were identified as important next steps toward sustainable dietary guidance related to the role of candy and other treats in a healthy lifestyle.

Factors that influence the reinforcing value of foods and beverages

Behavioral economic principles state that as the cost of a product increases, purchasing or consumption of that product will decrease. To understand the impact of behavioral economics on ingestive behavior, our laboratory utilizes an operant behavior paradigm to measure how much work an individual will engage in to get access to foods and beverages. This task provides an objective measure of the reinforcing value. We have shown that consumption of the same high fat snack food every day for two weeks reduces its reinforcing value in lean individuals, but increases its reinforcing value in a subset of obese individuals. This increase in the reinforcing value of food predicts future weight gain. Similarly, we have shown that repeated intake of caffeinated soda increases its reinforcing value in boys, but not in girls. This increase in reinforcing value is not related to usual caffeine consumption, but may be associated with positive, subjective effects of caffeine that are more likely to be reported by boys than by girls. Because food and beverage reinforcement relates to real-world consumption, it is important to determine factors that increase or decrease the reinforcing value and determine the consequences of these responses. We are especially interested in determining ways to shift the behavioral economic curve in order to develop novel strategies to decrease the reinforcing value of less healthy snack foods and beverages, such as soda, potato chips and candy and to increase the reinforcing value of healthier foods and beverages, such as water, fruits, and vegetables.

Food reinforcement, dietary disinhibition and weight gain in nonobese adults

OBJECTIVE

Food reinforcement is cross-sectionally related to BMI and energy intake in adults, and prospectively predicts weight gain in children, but there has not been any research studying 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 in a sample of 115 nonobese (BMI < 30) adults. Dietary disinhibition and dietary restraint were also examined as potential moderators of this relationship.

RESULTS

In a hierarchical regression controlling for baseline age and weight, dietary hunger, income, sex, and minority status, food reinforcement and predicted weight gain (P = 0.01) significantly increased the variance from 6.3% to 11.7% (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.

Acute and chronic effects of gum chewing on food reinforcement and energy intake

Although chewing gum has been considered a potential method for reducing energy intake, little empirical data exist to support this idea. The purpose of this study was to test the hypothesis that chewing gum before eating reduces motivation to eat, hunger, and energy intake. In order to test this hypothesis, we conducted two experiments in which participants chewed gum prior to completing a food reinforcement task or before all eating occasions for two of three weeks. In Experiment 1, we found that chewing gum had no influence on the reinforcing value of food, but chewing mint gum reduced liking of and energy intake from fruit. In addition, chewing gum reduced self-reported hunger immediately after gum chewing and after eating compared with the no gum condition. In Experiment 2, gum chewing had no significant effect on total energy intake, but participants consumed fewer meals, consumed more energy per meal, and had a lower nutrient adequacy ratio during the gum chewing weeks. These studies provide no evidence that acute or chronic gum chewing reduces hunger or energy intake. In fact, chewing mint-flavored gum may deter consumption of fruit and reduce diet quality.

Validation of an online questionnaire measure of the relative reinforcing value of food

Laboratory methods and questionnaires to assess the relative reinforcing value of food (RRV-F) have been developed, but this is the first study to validate an online questionnaire measure of the RRV-F. Participants (281 college students) completed an online survey assessing demographic variables, food preferences, and the RRV-F. A subsample (n=21) also completed a laboratory food choice session. The online RRV-F instrument showed strong predictive validity for laboratory food choice behavior, convergent validity with overweight status, and discriminant validity with unrelated constructs (age, gender, height). Results suggest that online methodology is appropriate for assessing the RRV-F in a manner that is cost-effective, time-efficient, affords greater anonymity, and enables recruitment from larger samples over a broader geographic region.

Meal timing and composition influence ghrelin levels, appetite scores and weight loss maintenance in overweight and obese adults

BACKGROUND

Although dietary restriction often results in initial weight loss, the majority of obese dieters fail to maintain their reduced weight. Diet-induced weight loss results in compensatory increase of hunger, craving and decreased ghrelin suppression that encourage weight regain. A high protein and carbohydrate breakfast may overcome these compensatory changes and prevent obesity relapse.

METHODS

In this study 193 obese (BMI 32.2±1.0kg/m(2)), sedentary non diabetic adult men and women (47±7years) were randomized to a low carbohydrate breakfast (LCb) or an isocaloric diet with high carbohydrate and protein breakfast (HCPb). Anthropometric measures were assessed every 4weeks. Fasting glucose, insulin, ghrelin, lipids, craving scores and breakfast meal challenge assessing hunger, satiety, insulin and ghrelin responses, were performed at baseline, after a Diet Intervention Period (Week 16) and after a Follow-up Period (Week 32).

RESULTS

At Week 16, groups exhibited similar weight loss: 15.1±1.9kg in LCb group vs. 13.5±2.3kg in HCPb group, p=0.11. From Week 16 to Week 32, LCb group regained 11.6±2.6kg, while the HCPb group lost additional 6.9±1.7kg. Ghrelin levels were reduced after breakfast by 45.2% and 29.5% following the HCPb and LCb, respectively. Satiety was significantly improved and hunger and craving scores significantly reduced in the HCPb group vs. the LCb group.

CONCLUSION

A high carbohydrate and protein breakfast may prevent weight regain by reducing diet-induced compensatory changes in hunger, cravings and ghrelin suppression. To achieve long-term weight loss, meal timing and macronutrient composition must counteract these compensatory mechanisms which encourage weight regain after weight loss.

Differences between liking and wanting signals in the human brain and relations with cognitive dietary restraint and body mass index

BACKGROUND

Eating behavior is determined, to a significant extent, by the rewarding value of food (ie, liking and wanting).

OBJECTIVE

We determined brain regions involved in liking and wanting and related brain signaling to body mass index (BMI; in kg/m(2)) and dietary restraint.

DESIGN

Fifteen normal-weight female subjects [mean ± SEM age: 21.5 ± 0.4 y; BMI: 22.2 ± 0.2] completed a food-choice paradigm by using visually displayed food items during functional magnetic resonance imaging scans. Two scans were made as follows: one scan was made in a fasted condition, and one scan was made in a satiated condition. The paradigm discriminated between liking and wanting, and subjects were offered items rated highly for wanting immediately after each scan. Imaging contrasts for high and low liking and wanting were made, and data for regions of interest were extracted. Activation related to liking and wanting, respectively, was determined. Outcomes were correlated to cognitive dietary restraint and BMI.

RESULTS

Dietary restraint predicted liking task-related signaling (TRS) in the amygdala, striatum, thalamus, and cingulate cortex (r = -0.5 ± 0.03, P < 0.00001). In the nucleus accumbens, the premeal liking and wanting TRS and premeal to postmeal liking TRS changes correlated positively with dietary restraint [bilateral average r = 0.6 ± 0.02, P < 0.04 (Bonferroni corrected)]. BMI and hunger predicted wanting TRS in the hypothalamus and striatum (P < 0.05). Postmeal liking TRS in the striatum, anterior insula, and cingulate cortex and wanting TRS in the striatum predicted the energy intake (liking: r = -0.3 ± 0.05, P < 0.0001; wanting: r = -0.3 ± 0.03, P < 0.00001).

CONCLUSIONS

Successful dietary restraint was supported by liking TRS from premeal to postmeal in the nucleus accumbens. Reward-related signaling was inversely related to BMI and energy intake, indicating reward deficiency.

Food reinforcement, energy intake, and macronutrient choice

BACKGROUND

Food is a powerful reinforcer that motivates people to eat. The relative reinforcing value of food (RRV(food)) is associated with obesity and energy intake and interacts with impulsivity to predict energy intake.

OBJECTIVE

How RRV(food) is related to macronutrient choice in ad libitum eating tasks in humans has not been studied; however, animal research suggests that sugar or simple carbohydrates may be a determinant of reward value in food. This study assessed which macronutrients are associated with food reinforcement.

DESIGN

Two hundred seventy-three adults with various body mass indexes were assessed for RRV(food), the relative reinforcing value of reading, food hedonics, energy intake in an ad libitum taste test, and usual energy intake derived from repeated 24-h dietary recalls. Multiple regression was used to assess the relation between predictors of total energy and energy associated with macronutrient intake after control for age, sex, income, education, minority status, and other macronutrient intakes.

RESULTS

The results showed that the relative proportion of responding for food compared with reading (RRV(prop)) was positively related to body mass index, laboratory-measured energy intake, and usual energy intake. In addition, RRV(prop) was a predictor of sugar intake but not of total carbohydrate, fat, or protein intake.

CONCLUSION

These results are consistent with basic animal research showing that sugar is related to food reward and with the hypothesis that food reward processes are more strongly related to eating than are food hedonics. This trial was registered at clinicaltrials.gov as NCT00962117.

Food reinforcement, delay discounting and obesity

Choice is a central construct in behavioral economics, with choice research divided into choice of concurrent alternative reinforcers, which is conceptualized as relative reinforcing value, or choice of small immediate versus larger delayed rewards, usually of the same commodity, which is conceptualized as delay of gratification and delay discounting. Relative reinforcing value, delay of gratification and delay discounting paradigms can be used to study obesity, which involves strong motivation to obtain and consume food reinforcers. Strong food reinforcement and difficulties in delay of gratification are risk factors for child weight gain, and both are related to individual differences in overweight/obesity. Delay discounting interacts with food reinforcement to predict energy intake. We provide a selective review of research on each of these areas, and argue that the division of choice into reinforcing value versus delay discounting is based on an arbitrary definition based on the temporality of choices. We present a model that integrates reinforcing value and delay discounting approaches. Implications of this theoretical approach to better understand excess energy intake and obesity are discussed. The paper represents an invited review by a symposium, award winner or keynote speaker at the Society for the Study of Ingestive Behavior [SSIB] Annual Meeting in Portland, July 2009.

Effects of daily snack food intake on food reinforcement depend on body mass index and energy density

BACKGROUND

The reinforcing value of food plays a role in food consumption. We have shown previously that daily intake of a high-energy-density (HED) snack food decreases food reinforcement and food liking in nonobese women but increases food reinforcement and decreases food liking in obese women.

OBJECTIVE

These previous studies were conducted with the use of only HED snack foods. The purpose of this study was to determine whether these effects generalize to low-energy-density (LED) foods.

DESIGN

Participants (n = 53) had food reinforcement and food liking tested at baseline and then again after 2 wk of daily consumption of 60-g portions of an HED (n = 26) or an LED (n = 27) snack food.

RESULTS

We observed a decrease in food reinforcement in women with a lower body mass index (BMI) and an increase in food reinforcement in women with a higher BMI after 14 d of consumption of an HED snack food. Food liking decreased in all women, regardless of BMI, after repeated consumption of HED foods. Conversely, all women, regardless of BMI, showed a decrease in food reinforcement after 14 d of LED snack food consumption. Women with a lower BMI who consumed LED snacks also showed a decrease in liking, but women with a higher BMI who consumed LED foods reported no change in liking.

CONCLUSIONS

These findings suggest that changes in food reinforcement after daily snack food intake are influenced by both BMI and the energy density of the foods. In addition, changes in food reinforcement cannot be explained by changes in food liking.

Differential effects of daily snack food intake on the reinforcing value of food in obese and nonobese women

BACKGROUND

Food reinforcement, ie, motivation to obtain food, is associated with energy intake and obesity. Finding ways to decrease the reinforcing value of unhealthy foods may help with adherence to diets and maintenance of weight loss. Our previous study in nonobese adults showed that daily consumption of the same snack food (food consumed apart from meals) for 14 d significantly decreased its reinforcing value.

OBJECTIVES

The aims of this study were to replicate and extend these findings to obese individuals and to examine the effects of different portion sizes of snack foods on food reinforcement.

DESIGN

Food reinforcement and liking were tested in 31 obese and 27 nonobese women at baseline and after 2 wk of daily consumption of 0, 100, or 300 kcal/d of the same snack food.

RESULTS

We found a significant interaction of phase, portion size, and body mass index on the pattern of operant responding for food. Obese women had a significant increase in food reinforcement after consuming the 300-kcal portion of food for 2 wk, whereas nonobese women had the opposite response. No significant differences were found on the reinforcing value with the 0- and 100-kcal portion-size conditions. Women in the 300-kcal group (obese and nonobese) reported a significant decrease in snack food liking from baseline to after daily intake.

CONCLUSIONS

These findings suggest that obese and nonobese women respond differently to the daily intake of a snack food and that this may not be a viable mechanism for reducing food reinforcement in obese women. This trial was registered at www.clinicaltrials.gov as NCT00837694.

Food branding influences ad libitum intake differently in children depending on weight status. Results of a pilot study

Environmental changes have facilitated the rapid increase in childhood obesity. One such change is increased presence of food marketing which promotes intake of high-fat, energy-dense foods. This study tested the hypotheses that overweight (OW) children are more sensitive to the intake-enhancing effects of food branding than non-OW children, and that the relationship between weight status and intake of branded foods is mediated by level of food brand awareness. Forty-three non-OW (n = 23) and OW (n = 20) children from diverse ethnic backgrounds participated in four dinnertime visits to test their intake of meals where food brands were present ("branded") or absent ("unbranded"). Food brand awareness was assessed by testing children's abilities to match food brand logos with correct foods and name specific brands from recall. Weight and height were measured on the first visit to determine BMI z-score and weight status. OW children consumed significantly more energy per meal than non-OW. Child age and brand awareness were positively associated. OW children consumed an additional 40 kcal in branded vs. unbranded meals whereas non-OW children consumed 45 kcal less in branded meals. Overweight children showed greater responsiveness to food branding, and they may be at risk in environments that are highly inundated with messages about food.