Eating Motives and the Controversy over Dieting: Eating Less Than Needed versus Less Than Wanted

Assessing the three types of dieting in the Three-Factor Model of dieting. The Dieting and Weight History Questionnaire

The construct of attempted eating restriction has been measured in a number of ways in recent years. The Three-Factor Model of Dieting suggests that dieting can be subdivided into three types: (1) frequency of past dieting and overeating (i.e., history of dieting), (2) current dieting to lose weight, and (3) weight suppression, or the difference between an individual's current weight and his or her highest previous weight. The purpose of this paper is to (1) describe the Dieting and Weight History Questionnaire (DWHQ), a measure that we have used for many years to assess these three dimensions of dieting; (2) provide some recent examples of published research on each type of dieting; (3) discuss some of the nuances of assessing these dieting types; and (4) suggest directions for future research.

Changes in weight control behaviors and hedonic hunger during a 12-week commercial weight loss program

Greater use of key self-regulatory behaviors (e.g., self-monitoring of food intake and weight) is associated with greater weight loss within behavioral weight loss treatments, although this association is less established within widely-available commercial weight loss programs. Further, high hedonic hunger (i.e., susceptibility to environmental food cues) may present a barrier to successful behavior change and weight loss, although this has not yet been examined. Adult men and women (N=111, body mass index M±SD=31.5±2.7kg/m(2)) were assessed before and after participating in a 12-week commercial weight loss program. From pre- to post-treatment, reported usage of weight control behaviors improved and hedonic hunger decreased, and these changes were inversely associated. A decrease in hedonic hunger was associated with better weight loss. An improvement in reported weight control behaviors (e.g., self-regulatory behaviors) was associated with better weight loss, and this association was even stronger among individuals with high baseline hedonic hunger. Findings highlight the importance of specific self-regulatory behaviors within weight loss treatment, including a commercial weight loss program developed for widespread community implementation. Assessment of weight control behavioral skills usage and hedonic hunger may be useful to further identify mediators of weight loss within commercial weight loss programs. Future interventions might specifically target high hedonic hunger and prospectively examine changes in hedonic hunger during other types of weight loss treatment to inform its potential impact on sustained behavior change and weight control.

Putting desire on a budget: dopamine and energy expenditure, reconciling reward and resources

Accumulating evidence indicates integration of dopamine function with metabolic signals, highlighting a potential role for dopamine in energy balance, frequently construed as modulating reward in response to homeostatic state. Though its precise role remains controversial, the reward perspective of dopamine has dominated investigation of motivational disorders, including obesity. In the hypothesis outlined here, we suggest instead that the primary role of dopamine in behavior is to modulate activity to adapt behavioral energy expenditure to the prevailing environmental energy conditions, with the role of dopamine in reward and motivated behaviors derived from its primary role in energy balance. Dopamine has long been known to modulate activity, exemplified by psychostimulants that act via dopamine. More recently, there has been nascent investigation into the role of dopamine in modulating voluntary activity, with some investigators suggesting that dopamine may serve as a final common pathway that couples energy sensing to regulated voluntary energy expenditure. We suggest that interposed between input from both the internal and external world, dopamine modulates behavioral energy expenditure along two axes: a conserve-expend axis that regulates generalized activity and an explore-exploit axes that regulates the degree to which reward value biases the distribution of activity. In this view, increased dopamine does not promote consumption of tasty food. Instead increased dopamine promotes energy expenditure and exploration while decreased dopamine favors energy conservation and exploitation. This hypothesis provides a mechanistic interpretation to an apparent paradox: the well-established role of dopamine in food seeking and the findings that low dopaminergic functions are associated with obesity. Our hypothesis provides an alternative perspective on the role of dopamine in obesity and reinterprets the "reward deficiency hypothesis" as a perceived energy deficit. We propose that dopamine, by facilitating energy expenditure, should be protective against obesity. We suggest the apparent failure of this protective mechanism in Western societies with high prevalence of obesity arises as a consequence of sedentary lifestyles that thwart energy expenditure.

Orofacial reactivity to the sight and smell of food stimuli. Evidence for anticipatory liking related to food reward cues in overweight children

Whether food liking may be a risk factor of overconsumption and overweight/obesity remains a controversial issue. So far, most studies used subjective reports to assess consummatory behavior, approaches that might overlook subtle or implicit hedonic changes to sensory properties of foods. Therefore, we used a cue-exposure approach by recording different measures of hedonic processes (orofacial reactivity, self-rated pleasantness, food preference) in 6-11 years old overweight (n=20) and normal-weight (n=20) children. Children were exposed to the smell and sight of high and low-energy density food stimuli and to non-food stimuli during pre- and post-prandial states. Their facial and verbal responses were videotaped and parent's reports of children's eating styles and appetitive traits were collected using the Children's Eating Behavior Questionnaire (CEBQ). Results showed that orofacial reactivity, as an objective measure of anticipatory liking, was more discriminative than self reports, with overweight children displaying more lip sucking than normal-weight children when exposed to high energy food pictures and to food odorants. Orofacial reactivity to food cues was also associated with BMI and children's eating styles (food responsiveness, emotional overeating, and desire to drink). Finally, overweight children classified more frequently non-food odorants as members of the food category during the pre-prandial state than during the post-prandial state, suggesting a possible influence of affective/motivational bias on odor categorization. Our findings suggest that orofacial responsiveness may be relevant to assess the sensitivity to energy-dense food reward cues in overweight children and for signaling, as an index of anticipatory liking, a potential risk for the development of overweight/obesity.

Comparing thought suppression and acceptance as coping techniques for food cravings

Handling food cravings seems to play a major role in weight management. Many try to simply avoid cravings. However, avoidance based techniques like thought suppression can make attempts to deal with cravings more difficult. Recent research suggests that acceptance based techniques, such as defusion, may be a plausible alternative. The current study aimed to compare these two techniques. Participants were instructed in either a thought suppression or defusion technique at the beginning of a week-long period of attempted chocolate abstinence. A control group was given no instruction. It was predicted that the participants given the defusion intervention would eat less chocolate during six days and during a final taste test. It was found that participants in the defusion group ate significantly less chocolate during the taste test than other groups. However, no difference was found in the amount of chocolate eaten throughout the duration of the experiment. The results are discussed in terms of the possible utility of acceptance based techniques in promoting weight management.

Dopaminergic enhancement of local food-seeking is under global homeostatic control

Recent work has implicated dopaminergic mechanisms in overeating and obesity with some researchers suggesting parallels between the dopamine dysregulation associated with addiction and an analogous dysregulation in obesity. The precise role of dopamine in mediating reward and reinforcement, however, remains controversial. In contrast to drugs of abuse, pursuit of a natural reward, such as food, is regulated by homeostatic processes that putatively maintain a stable energy balance keeping unrestrained consumption and reward pursuit in check. Understanding how the reward system is constrained by or escapes homeostatic regulation is a critical question. The widespread use of food restriction to motivate animal subjects in behavior paradigms precludes investigation of this relationship as the homeostatic system is locked into deficit mode. In the present study, we examined the role of dopamine in modulating adaptive feeding behavior in semi-naturalistic homecage paradigms where mice earn all of their food from lever pressing. We compared consumption and meal patterning between hyperdopaminergic dopamine transporter knock-down and wild-type mice in two paradigms that introduce escalating costs for procuring food. We found that hyperdopaminergic mice exhibited similar demand elasticity, weight loss and energy balance in response to cost. However, the dopamine transporter knock-down mice showed clear differences in meal patterning. Consistent with expectations of enhanced motivation, elevated dopamine increased the meal size and reduced intrameal cost sensitivity. Nonetheless, this did not alter the overall energy balance. We conclude that elevated dopamine enhances the incentive or willingness to work locally within meals without shifting the energy balance, enhancing global food-seeking or generating an energy surplus.

Assessing food appeal and desire to eat: the effects of portion size & energy density

BACKGROUND

Visual presentation of food provides considerable information such as its potential for palatability and availability, both of which can impact eating behavior.

METHODS

We investigated the subjective ratings for food appeal and desire to eat when exposed to food pictures in a fed sample (n=129) using the computer paradigm ImageRate. Food appeal and desire to eat were analyzed for the effects of food group, portion size and energy density of the foods presented as well as by participant characteristics.

RESULTS

Food appeal ratings were significantly higher than those for desire to eat (57.9±11.6 v. 44.7±18.0; p<0.05). Body mass index was positively correlated to desire to eat (r=0.20; p<0.05), but not food appeal. Food category analyses revealed that fruit was the highest rated food category for both appeal and desire, followed by discretionary foods. Additionally, overweight individuals reported higher ratings of desire to eat large portions of food compared to smaller portions (p<0.001), although these effects were relatively small. Energy density of the foods was inversely correlated with ratings for both appeal and desire (r's=-0.27; p's<0.01).

CONCLUSIONS

Results support the hypothesis that individuals differentiate between food appeal and desire to eat foods when assessing these ratings using the same type of metric. Additionally, relations among food appeal and desire to eat ratings and body mass show overweight individuals could be more responsive to visual foods cues in a manner that contributes to obesity.

Ecological momentary assessment of obesogenic eating behavior: combining person-specific and environmental predictors

Obesity has been promoted by a food environment that encourages excessive caloric intake. An understanding of how the food environment contributes to obesogenic eating behavior in different types of individuals may facilitate healthy weight control efforts. In this study, Ecological Momentary Assessment (EMA) via palmtop computers was used to collect real-time information about participants' environment and eating patterns to predict overeating (i.e., greater than usual intake during routine meals/snacks, and eating outside of a participant's normal routine) that could lead to weight gain. Thirty-nine women (BMI = 21.6 ± 1.8; age = 20.1 ± 2.0 years; 61% white) of normal weight (BMI 18.5-25) completed the Three Factor Eating Questionnaire and the Power of Food Scale (PFS), and carried a palmtop computer for 7-10 days, which prompted them to answer questions about eating events, including a count of the types of good tasting high-calorie foods that were available. None of the self-report measures predicted overeating, but BMI interacted with the number of palatable foods available to predict overeating (P = 0.035). Compared to leaner individuals who reported a relatively low frequency of overeating regardless of the availability of palatable food, the probability of overeating among heavier individuals was very low in the absence of palatable food, but quickly increased in proportion to the number of palatable foods available. Our findings suggest that the eating behavior of those with higher relative weights is susceptible to the presence of palatable foods in the environment. Individuals practicing weight control may benefit from limiting their exposure to good tasting high-calorie food in their immediate environment.

Weight, gender, and snack appeal

In this study, we hypothesized that overweight/obese persons have an exaggerated approach tendency toward high calorie foods. Testing this hypothesis, a stimulus response compatibility (SRC) task was used to assess approach-avoidance tendencies toward food in both overweight/obese participants (n=42), and normal weight controls (n=46). The SRC task is a reaction time task measuring how fast one approaches and avoids pictures of food and non-foods according to given instructions. It was found that overweight/obese men are slower at avoiding particularly high calorie snack foods. But this does not appear to be the case for overweight/obese women who showed nearly as fast avoidance as approach toward the high calorie food cues. It is concluded that overweight/obese women, rather than men, are ambivalent toward high calorie foods, which is the likely result of high dietary restraint.

A mindful eating group as an adjunct to individual treatment for eating disorders: a pilot study

The objective of this study was to investigate potential benefits of a Mindful Eating Group as an adjunct to long-term treatment for a variety of eating disorders. Individuals (N = 33) attending treatment at an outpatient treatment facility participated in the 10-week intervention designed to enhance awareness around hunger and satiety cues. Disordered eating symptoms were assessed pre- and post-intervention using the EAT-26. Significant reductions were found on all subscales of the EAT-26 with large effect sizes. No significant differences were identified between eating disorder diagnoses. Results suggest potential benefits of an adjunct mindfulness group intervention when treating a variety of eating disorders. Limitations are discussed.

Binge eating, purging, or both: eating disorder psychopathology findings from an internet community survey

OBJECTIVE

This study aimed to compare bulimia nervosa (BN), binge eating disorder (BED), and purging disorder (PD) on clinically significant variables and examine the utility of once versus twice-weekly diagnostic thresholds for disturbed eating behaviors.

METHOD

234 women with BN, BED, or PD were identified through self-report measures via an online survey and categorized based on either once-weekly or twice-weekly disturbed eating behaviors.

RESULTS

BN emerged as a more severe disorder than BED and PD. The three groups differed significantly in self-reported restraint and disinhibition and the BN and BED groups reported higher levels of depression than PD. For BN, those engaging in behaviors twice-weekly versus once-weekly were more symptomatic.

DISCUSSION

The BN, BED, and PD groups differed in clinically meaningful ways. Future research need to clarify the relationship between mood disturbances and eating behaviors. Reducing the twice-weekly behavior threshold for BN would capture individuals with clinically significant eating disorders, though the twice-weekly threshold may provide important information about disorder severity for both BN and BED.

The diagnosis of eating disorders in adults with learning disabilities: Conceptualisation and implications for clinical practice

OBJECTIVE

The literature suggests that less attention has been afforded to eating disorders (EDs) in adults with learning disabilities (LDs) than in adults of normal intellect. This review aimed to examine the methods, prevalence and implications of an ED diagnosis in adults with LDs.

METHOD

Key texts, journals and online databases were searched for literature examining disordered eating in adults with LDs.

RESULTS

A review of the extant literature revealed that a range of dysfunctional eating behaviours have been classified as 'eating disorders' and highlighted a lack of clarity about the distinction between feeding and EDs. A small body of research suggests that some individuals with LDs show the emotional and cognitive characteristics of typical EDs.

DISCUSSION

The lack of consensus about conceptualisation, assessment, diagnosis and treatment of EDs in individuals with LDs needs to be addressed in order to aid awareness and enhance clinical approaches for this population.

Psychobiological traits in the risk profile for overeating and weight gain

Our dramatically changed food environment--since periods in our history when food sources were highly constrained--has presented new challenges for obesity research. For example, these alterations have strongly emphasized the physiological differences between the homeostatic and the hedonic regulation of food intake--the latter being largely responsible for the pronounced increase in obesity in the past few decades. There is also increasing agreement that compulsive overeating shares many parallels with addiction disorders such as drug abuse. These factors have also fostered a renewed interest in identifying individual differences in personality and motivational systems that increase the risk for overeating and weight gain in our population. Reward sensitivity has been the focus of a recent body of compelling research, with evidence favoring two seemingly opposite points of view. On the one hand, studies have found support for a link between low reward sensitivity and obesity, whereas other evidence suggests that a strong appetitive motivation leads to overeating and weight gain. Arguments are provided to reconcile these apparently disparate theories. Finally, the role of impulsivity and its links with symptoms of attention deficit/hyperactivity disorder are discussed, as well as their respective roles in the risk profile for obesity.

Hedonic and motivational roles of opioids in food reward: implications for overeating disorders

Food reward can be driven by separable mechanisms of hedonic impact (food 'liking') and incentive motivation (food 'wanting'). Brain mu-opioid systems contribute crucially to both forms of food reward. Yet, opioid signals for food 'liking' and 'wanting' diverge in anatomical substrates, in pathways connecting these sites, and in the firing profiles of single neurons. Divergent neural control of hedonic and motivational processes raises the possibility for joint or separable modulation of food intake in human disorders associated with excessive eating and obesity. Early findings confirm an important role for 'liking' and 'wanting' in human appetitive behaviors, and suggest the intriguing possibility that exaggerated signals for 'wanting,' and perhaps 'liking,' may contribute to forms of overeating.

Sensitivity to reward and punishment in eating disorders

The aim of this review was to collate and summarise the self-report data regarding anomalies in sensitivity to reward and punishment in eating disorders (ED) with use of a meta-analysis where possible. Electronic databases were searched to December 2008. Studies were required to have a non-eating disorder healthy control group and include at least one self-report measure of sensitivity to reward or punishment in an eating disorder population. Findings were very heterogeneous and inconsistencies between studies and measures were highlighted. In general, patients with anorexia nervosa (restricting type) were less sensitive to reward than healthy controls, whereas patients with bulimia nervosa and anorexia nervosa (binge/purge) type were more sensitive. All ED groups report higher sensitivity to punishment than healthy controls. Individuals with eating disorders differ from healthy controls in measures of reward and punishment sensitivity as measured using the Temperament and Character Inventory, Tridimensional Personality Questionnaire and BIS/BAS scales, but further work is required as there is some heterogeneity in the data. Generating more research using behavioural measures may increase understanding of the findings.

Dopamine and binge eating behaviors

Central dopaminergic mechanisms are involved in the motivational aspects of eating and food choices. This review focuses on human and animal data investigating the importance of dopamine on binge eating behaviors. Early work examining dopamine metabolites in the cerebrospinal fluid and plasma of bulimic individuals suggested decreased dopamine turnover during the active phase of the illness. While neuroimaging studies of dopamine mechanisms in bulimia nervosa (BN) and binge eating disorder (BED) are limited, genetic studies in humans have implicated an increased frequency of dopamine transporter and associated D2 receptor polymorphisms with binge pathology. Recent studies in rodent models of dietary-induced binge eating (DIBE) have investigated plausible dopamine mechanisms involved in sustaining binge eating behaviors. In DIBE models, highly palatable foods (fats, sugars and their combination), as well as restricted access conditions appear to promote ingestive responses and result in sustained dopamine stimulation within the nucleus accumbens. Taken together with studies on the comorbidity of illicit drug use and eating disorders, the data reviewed here support a role for dopamine in perpetuating the compulsive feeding patterns of BN and BED. As such, we propose that sustained stimulation of the dopamine systems by bingeing promoted by preexisting conditions (e.g., genetic traits, dietary restraint, stress, etc.) results in progressive impairments of dopamine signaling. To disrupt this vicious cycle, novel research-based treatment options aiming at the neural substrates of compulsive eating patterns are necessary.

The Influence of Taxes and Subsidies on Energy Purchased in an Experimental Purchasing Study

There is limited research on how taxes and subsidies would influence the energy and nutritional quality of food purchases. Using an experimental analogue purchasing task, we examined the effects of increasing the price of high-calorie-for-nutrient foods or reducing the price of low-calorie-for-nutrient foods by 12.5% and 25% on mothers’ purchases of 68 common foods and drinks. Taxing less healthy foods with low nutrient density reduced energy (caloric) intake, while reducing the proportion of fat and increasing the proportion of protein purchased. Subsidizing more healthful foods with high nutrient density increased energy intake, without changing the macronutrient profile of foods purchased. These results favor taxes as a way to reduce caloric intake.

Leptin and the systems neuroscience of meal size control

The development of effective pharmacotherapy for obesity will benefit from a more complete understanding of the neural pathways and the neurochemical signals whose actions result in the reduction of the size of meals. This review examines the neural control of meal size and the integration of two principal sources of that control--satiation signals arising from the gastrointestinal tract and CNS leptin signaling. Four types of integrations that are central to the control of meal size are described and each involves the neurons of the nucleus tractus solitarius (NTS) in the dorsal hindbrain. Data discussed show that NTS neurons integrate information arising from: (1) ascending GI-derived vagal afferent projections, (2) descending neuropeptidergic projections from leptin-activated arcuate and paraventricular nucleus neurons, (3) leptin signaling in NTS neurons themselves and (4) melanocortinergic projections from NTS and hypothalamic POMC neurons to NTS neurons and melanocortinergic modulation of vagal afferent nerve terminals that are presynaptic to NTS neurons.

Managing the pandemic of obesity: siding with the fox or the hedgehog?

Obesity is a major public health problem of pandemic proportion. Despite its high prevalence and widespread distribution (consistent with a common underlying etiology), clinical psychologists and primary care physicians routinely approach the problem with individualized but often ineffective treatments like psychotherapy and pharmacotherapy, or propose alterations to specific components of the 'toxic environment', cultural influences, and psychosocial factors purported to cause overeating. This paper presents an alternative perspective and proposes a potential framework for assisting health professionals in developing rational approaches to education about and preventive treatment of obesity based on the role of factors in early life that contribute to personality and behavior and which over time lead to obesity and its maintenance.

Are dietary restraint scales valid measures of dietary restriction? Additional objective behavioral and biological data suggest not

Prospective studies find that individuals with elevated dietary restraint scores are at increased risk for bulimic symptom onset, yet experiments find that assignment to energy-deficit diet interventions reduce bulimic symptoms. One explanation for the conflicting findings is that the dietary restraint scales used in the former studies do not actually identify individuals who are restraining their caloric intake. Thus, we tested whether dietary restraint scales showed inverse relations to objectively measured caloric intake in three studies. Four dietary restraint scales did not correlate with doubly labeled water estimates of caloric intake over a 2-week period (M, r=.01). One scale showed a significant inverse correlation with objectively measured caloric intake during a regular meal ordered from an ecologically valid menu (M, r=-.30), but a significant positive relation that was qualified by a significant quadratic effect, to objectively measured caloric intake during multiple eating episodes in the lab (M, r=.32). In balance, results suggest that dietary restraint scales are not valid measures of dietary restriction, replicating findings from prior studies that examined objective measures of caloric intake.

Adding cognitive therapy to dietetic treatment is associated with less relapse in obesity

OBJECTIVE

The treatment of obesity is universally disappointing; although usually some weight loss is reported directly after treatment, eventual relapse to, or even above, former body weight is common. In this study it is tested whether the addition of cognitive therapy to a standard dietetic treatment for obesity might prevent relapse. It is argued that the addition of cognitive therapy might not only be effective in reducing weight and related concerns, depressed mood, and low self-esteem, but also has an enduring effect that lasts beyond the end of treatment.

METHODS

Non-eating-disordered overweight and obese participants in a community health center (N=204) were randomly assigned to a group dietetic treatment+cognitive therapy or a group dietetic treatment+physical exercise.

RESULTS

Both treatments were quite successful and led to significant decreases in BMI, specific eating psychopathology (binge eating, weight-, shape-, and eating concerns) and general psychopathology (depression, low self-esteem). In the long run, however, the cognitive dietetic treatment was significantly better than the exercise dietetic treatment; participants in the cognitive dietetic treatment maintained all their weight loss, whereas participants in the physical exercise dietetic treatment regained part (25%) of their lost weight.

CONCLUSION

Cognitive therapy had enduring effects that lasted beyond the end of treatment. This potential prophylactic effect of cognitive therapy is promising; it might be a new strategy to combat the global epidemic of obesity.

Dieting, restraint, and disinhibition predict women's weight change over 6 y

BACKGROUND

Although disinhibited eating is positively associated with higher weight in women, it is not known whether restrained eating and dieting moderate the influence of disinhibited eating on weight change.

OBJECTIVE

The objective was to investigate over 6 y the interactive effects of restrained and disinhibited eating and self-reported dieting to lose weight as predictors of weight gain in women.

DESIGN

Data were collected from non-Hispanic white women (n = 163) every 2 y. Height and weight were measured in triplicate. Dietary restraint and disinhibition were assessed by using the Eating Inventory. Participants were also asked if they were "currently dieting to lose weight." Multilevel modeling was used to examine change in weight as a function of time-invariant and time-varying predictors, including dietary restraint, dietary disinhibition, and self-reported dieting.

RESULTS

After covariates were adjusted for, growth curve models showed that within-person increases in restraint over time were associated with concurrent decreases in weight and that higher levels of restraint moderated the positive association between dietary disinhibition and weight. Women who reported dieting at study entry were heavier at study entry and gained more weight over time than did nondieters. Finally, a significant interaction between restraint, disinhibition, and dieting showed that restraint moderated the effect of disinhibition on weight differently in nondieters than in dieters.

CONCLUSIONS

Increasing levels of dietary restraint may be beneficial in moderating weight by attenuating the positive association between disinhibition and weight in dieting women. An understanding of weight and weight change requires examination of the interactive effects of restraint, disinhibition, and dieting.

Repeated binge access to a palatable food alters feeding behavior, hormone profile, and hindbrain c-Fos responses to a test meal in adult male rats

Repetitive cycles of palatable food access and chronic calorie restriction alter feeding behaviors and forebrain neural systems. The purpose of this study was to determine the behavioral, endocrine, and meal-related hindbrain neural activation in adult male Sprague-Dawley rats exposed to a binge-access feeding schedule. The binge-access schedule consisted of repeated twice-per-week episodes of acute calorie restriction (to one-third of the previous day's intake) followed by 2 h of concurrent access to high-calorie palatable food (sweetened fat: 90% vegetable shortening-10% sucrose) and chow. The binge-access rats consumed more calories during the "binge" period than rats with continuous access to sweetened fat (continuous-access group) or subjected to repeated acute calorie restriction only (chow-restricted group). The binge-access group also exhibited a approximately 25% increase in sweetened fat intake from week 1 to week 6. Persistence of the binge phenotype in the binge-access animals was demonstrated 2 wk, but not 4 wk, after ad libitum chow. The binge-access and chow-restricted groups maintained a similar normal body composition and hormonal profiles, whereas the continuous-access animals developed an obese phenotype. Terminal ghrelin levels were significantly higher in the binge-access group than in the continuous-access group. Consumption of a standardized meal resulted in more c-Fos-positive cells along the anterior-posterior nucleus of the solitary tract regions in the binge-access group than in naive controls. These results suggest that repeated cycles of acute calorie restriction followed by palatable food produce physiological alterations that may facilitate overconsumption of a highly palatable food during limited-access periods.

The Power of Food Scale. A new measure of the psychological influence of the food environment

This paper describes the psychometric evaluation of a new measure called the Power of Food Scale (PFS). The PFS assesses the psychological impact of living in food-abundant environments. It measures appetite for, rather than consumption of, palatable foods, at three levels of food proximity (food available, food present, and food tasted). Participants were 466 healthy college students. A confirmatory factor analysis replicated the three-factor solution found previously by Capelleri et al. [Capelleri, J. C., Bushmakin, A. G., Gerber, R. A., Leidy, N. K., Sexton, C., Karlsson, J., et al. (in press). Discovering the structure of the Power of Food Scale (PFS) in obese patients. International Journal of Obesity, 11, A165]. The PFS was found to have adequate internal consistency and test-retest reliability. The PFS and the Restraint Scale were regressed on four self-report measures of overeating. The PFS was independently related to all four whereas the Restraint Scale was independently related to two. Expert ratings of items suggested that the items are an acceptable reflection of the construct that the PFS is designed to capture. The PFS may be useful as a measure of the hedonic impact of food environments replete with highly palatable foods.

Regimented and lifestyle restraint in binge eating disorder

OBJECTIVE

This study tested the psychometric properties of two commonly used measures of dietary restraint, the Three Factor Eating Questionnaire and the Eating Disorder Examination Questionnaire.

METHOD

Restraint data from 512 overweight/obese participants with binge eating disorder (BED) were subjected to exploratory and confirmatory factor analyses.

RESULTS

Factor analyses of the restraint variables indicated a two-factor solution, interpreted as "Regimented" and "Lifestyle" restraint. Stepwise regression analyses revealed that Regimented restraint was more predictive of eating pathology, whereas Lifestyle restraint appeared to be protective of eating problems. Neither type of restraint was related to binge eating. Cluster analysis of the restraint dimensions yielded three distinct subgroups of patients who differed significantly on several important eating- and weight-related features.

DISCUSSION

Future research is needed to test the significance of these restraint constructs over time in both the development of obesity and binge eating problems as well as their treatment.

The Pavlovian power of palatable food: lessons for weight-loss adherence from a new rodent model of cue-induced overeating

Objective

Relapsing to overeating is a stubborn problem in obesity treatment. We tested the hypothesis that context cues surrounding palatable food (PF) intake have the power to disrupt caloric regulation even of less PF. Context cues are non-food cues that are in the environment where PF is habitually eaten.

Design

Rats were conditioned to associate intake of Oreo cookies as the PF to cages with distinct context cues that differed from cues in cages were they were only given chow. PF naturally stimulated greater caloric intake. The rats were then tested in the PF cage with only chow available to determine if the PF-paired cues, alone, could elicit overeating of plain chow.

Subjects

Non food-deprived female Sprague-Dawley rats.

Measurements

Intake of plain chow under PF-paired cues vs. chow-paired cues was compared. This was also measured in tests that included a morsel of PF as a priming stimulus. We also controlled for any effect of binge-prone vs. binge–resistant status to predict cued-overeating.

Results

Rats consumed significantly more chow when exposed to context cues previously paired with PF than with chow (p<0.01). This effect occurred using various cues (e.g., different types of bedding or wallpaper). The effect was strengthened by priming with a morsel of PF (p<0.001) and was unaffected by baseline differences in propensity to binge on PF.

Conclusion

Context-cues associated with PF intake can drive overeating even of a less PF and abolish the ability of rats to compensate for the calories of a PF primer. Just as drug-associated context cues can reinstate drug-addiction relapse, PF-paired cues may trigger overeating relapses linked to weight regain and obesity. This model should help identify the reflex-like biology that sabotages attempts to adhere to healthy reduced calorie regimens and call greater attention to the cue-factor in the treatment of binge-eating and obesity.

Can we apply the dual-pathway model of overeating to a population of weight-preoccupied overweight women?

OBJECTIVE

The aim of the study is to verify the applicability of the dual-pathway model among weight-preoccupied overweight women and to document the restraint pathway, the negative affect pathway, and the possibility of a direct pathway from body dissatisfaction to overeating.

METHOD

Structural equations were performed to test the model on baseline data of 153 weight-preoccupied overweight women recruited to participate in a randomized trial.

RESULTS

Findings suggest that the model obtains satisfactory fit. Although the restraint pathway is partially supported, the negative affect pathway is confirmed. A third pathway linking directly body dissatisfaction to overeating is also evidenced.

DISCUSSION

The dual-pathway model of overeating seems to be representative of the reality of weight-preoccupied overweight women, which could be pointed as a population in need of clinical attention, particularly considering the dramatically increasing rates of obesity.

Food volume effects on intake and appetite in women with binge-eating disorder and weight-matched controls

OBJECTIVE

Our study examined the effect of food volume on later intake and appetite ratings in 15 women with binge eating disorder (BED) and 15 healthy control women.

METHOD

On nonconsecutive days, lower-volume (250 ml/171 kcal) and higher-volume milk-based preloads (500 ml/171 kcal) were served in counterbalanced order. Thirty minutes later, appetite ratings and intake at a buffet-style test-lunch were assessed.

RESULTS

Higher-volume preloads decreased hunger, desire to eat, excitement about eating, desire for dessert, and loss of control over eating at test meals, relative to lower-volume preloads. Test-meal intake was greater among BED participants than controls; intake did not differ by preload volume. BED participants' desire to eat, prospective consumption, excitement about eating, and desire for meals and desserts were higher than controls' ratings.

CONCLUSION

Higher-volume foods decreased hunger and related appetite ratings. Differences in food intake and appetite between BED and control participants provide further evidence for the validity of test meals to assess binge eating.

Military experience strongly influences post-service eating behavior and BMI status in American veterans

In-depth interviews were conducted with veterans (n=64) with an average age of 57 years to investigate eating behavior and food insecurity during military service and examine if it affects post-war eating behavior, and if this contributes to the high incidence of obesity found in veterans. About half of the subjects served during the Vietnam War, while smaller numbers served in WWII, the Korean War, Desert Storm, or other conflicts. The mean BMI was 30.5+/-6.7 kg/m(2). Only 12.5% of participants were classified as normal weight, while 37.5% were overweight, 46.9% were obese, and 3.1% were classified as excessively obese. Five major themes were identified including, (a) military service impacts soldier's food environment, (b) food insecurity influences eating behavior and food choices, (c) military impacts weight status during and post-service, (d) military service has health consequences, and (e) post-service re-adjustment solutions are needed to ease re-entry into civilian life.

Relationship between eating behaviours and food and drink consumption in healthy postmenopausal women in a real-life context

Associations between eating behaviours and dietary variables have not been thoroughly investigated in healthy postmenopausal women in a real-life uncontrolled context. To investigate how eating behaviours (cognitive dietary restraint, disinhibition and susceptibility to hunger) were associated with food and drink consumption, energy density and meal pattern in 112 healthy postmenopausal women (age 56·8 (sd 4·4) years) not on hormonal therapy. Women completed a 3 d weighed food record and filled out the Three-Factor Eating Questionnaire. The sample was divided according to the median of the distribution of cognitive dietary restraint and disinhibition (9 and 6 respectively). Both subgroups of women with high restraint level (presenting either high or low disinhibition) consumed a diet with a lower energy density than subgroups of women with lower restraint level. Women with high restraint–low disinhibition had a lower consumption of red meat and processed meat and a lower consumption of diet soft drinks than women with low restraint–high disinhibition. They were also characterised by a higher intake of whole grains than women with high restraint–high disinhibition and than women with lower restraint level (with either high or low disinhibition). Women with high restraint–high disinhibition levels showed differences in dietary variables when compared with subgroups of women with lower restraint level, namely for refined grains and diet soft drinks. We conclude that in healthy postmenopausal women, dietary consumption of specific food and drink may be related to particular eating behaviours. Women with high restraint and low disinhibition levels generally showed the most healthy dietary pattern.

Access conditions affect binge-type shortening consumption in rats

When non-food-deprived rats are given intermittent access to certain substances, consumption of those substances is greater than when more frequent access is provided. The present study examined the effects of three different shortening access conditions on subsequent shortening intake in rats. Each of the three different shortening conditions lasted five weeks and was followed by a five-week period in which shortening access was limited by time (1 h of availability) on either an Intermittent (Monday, Wednesday, Friday) or Daily schedule of access. In Part 1, limiting the quantity of shortening provided during the 1-h period of availability attenuated subsequent 1-h shortening intake in the Intermittent access group, but had no statistically significant effect in the Daily access group. In Part 2, unrestricted availability of shortening (24 h/day-7 days/week) attenuated subsequent 1-h shortening intake in all groups. In Part 3, shortening non-availability for five weeks enhanced subsequent 1-h shortening intake in all groups. It was also shown that rats under an Intermittent, but not a Daily, schedule of access consumed as much shortening during a 1-h period of availability, as was consumed in 24 h when shortening availability was unrestricted. These results demonstrate that while intermittent access is necessary and sufficient to stimulate binge-type eating in rats, the behavioral history can modulate binge size.

Daily consumption of individual snack foods decreases their reinforcing value

The reinforcing value of food is one factor that influences energy intake. The purpose of this study was to determine if the reinforcing value of highly liked snack foods could be modified by restriction or daily intake of individual preferred foods in the absence of changes in total energy intake. Food reinforcement was tested at baseline and after each of two, two-week phases. During the restriction phase, participants did not eat a target food or closely related foods while during the daily intake phase, participants consumed a 200-300 kcal portion of the target food daily. The reinforcing value of the target food significantly decreased after two weeks of daily intake. Restriction did not change food reinforcement. These data suggest that eating a portion of a highly palatable food every day decreases its reinforcing value. Implications for weight control are discussed.

Ovarian hormones inhibit fat intake under binge-type conditions in ovariectomized rats

Binge eating is more common in females than in males. This study investigated the effects of ovarian hormones on binge-eating behavior in a diet-related rat model. Six groups of ovariectomized Sprague-Dawley rats were used (n=13/group). All rats had continuous access to chow and water throughout the study. One half of the rats were injected every fourth day with estradiol benzoate (2 microg/100 microl sesame oil) and progesterone (500 microg/100 microl sesame oil); the other half received only the sesame oil vehicle. Three feeding protocols were tested in each hormone injection condition: (1) chow only: no additional dietary fat access; (2) low-restriction: 1-h fat access every day; (3) high-restriction: 1-h fat access on Monday, Wednesday, and Friday. As previously reported in intact male and female rats, the high-restriction groups exhibited binge-like increases in 1-h energy intake during fat access. The major new finding of this study is that 1-h energy intake was tonically, but not cyclically, reduced in the hormone-treated high-restriction (binge) rats. Specifically, both low- and high-restriction hormone-treated rats consumed significantly less energy than did the oil-treated rats during the 1-h fat period (p<0.0001) and overall (p<0.0001), indicating a tonic inhibition of eating. However, food intake during the 1-h fat access period was also cyclically reduced in the hormone-treated low-restriction rats, but not in the hormone-treated high-restriction rats. These results indicate that the normal cyclic inhibitory influence of ovarian hormones on eating, but not their normal tonic inhibitory influence, is disrupted by conditions leading to binge-type eating.