Food craving and food "addiction": a critical review of the evidence from a biopsychosocial perspective

From disordered eating to addiction: the "food drug" in bulimia nervosa

The high prevalence of substance abuse in individuals with bulimia nervosa (BN) and the pervasive symptom substitution in many types of drug addiction suggest that a number of substances--including food--can impair an individual's self-control, even in the presence of negative consequences. Nonetheless, the neurobiological similarities between BN and drug addiction are not clearly established. This review explores how the specific eating patterns seen in BN (binge eating and purging, with intermittent dietary restriction) are particularly addictive and differentiate BN from other eating disorders and obesity. A number of peripheral and central biological aberrations seen in BN may result in altered reward sensitivity in these individuals, particularly through effects on the dopaminergic system. Neurobiological findings support the notion that BN is an addictive disorder, which has treatment implications for therapy and pharmacological manipulations.

Rationale and consequences of reclassifying obesity as an addictive disorder: neurobiology, food environment and social policy perspectives

The rapid increase in the prevalence of obesity is a priority for investigators from across numerous disciplines, including biology, nutritional science, and public health and policy. In this paper, we systematically examine the premise that common dietary obesity is an addictive disorder, based on the criteria for addiction described in the Diagnostic and Statistical Manual (DSM) of Mental Disorders of the American Psychiatric Association, version IV, and consider the consequences of such a reclassification of obesity for public policy. Specifically, we discuss evidence from both human and animal studies investigating the effects of various types and amounts of food and the food environment in obese individuals. Neurobiological studies have shown that the hedonic brain pathways activated by palatable food overlap considerably with those activated by drugs of abuse and suffer significant deficits after chronic exposure to high-energy diets. Furthermore, food as a stimulus can induce the sensitization, compulsion and relapse patterns observed in individuals who are addicted to illicit drugs. The current food environment encourages these addictive-like behaviors where increased exposure through advertisements, proximity and increased portion sizes are routine. Taking lessons from the tobacco experience, it is clear that reclassifying common dietary obesity as an addictive disorder would necessitate policy changes (e.g., regulatory efforts, economic strategies, and educational approaches). These policies could be instrumental in addressing the obesity epidemic, by encouraging the food industry and the political leadership to collaborate with the scientific and medical community in establishing new and more effective therapeutic approaches.

Non-food odorants reduce chocolate cravings

The present study compared the relative effectiveness of simple, commercially available food and non-food olfactory tasks on chocolate craving reduction. Chocolate cravings were induced by a series of coloured photographs and 67 undergraduate women were asked to smell one of three odours (green apple, jasmine, or water). The non-food odorant (jasmine) significantly reduced chocolate cravings relative to both the food and control odorants. Thus simple non-food odorants offer potential scope as a technique for curbing unwanted food cravings.

Nutritional sensing and its utility in treating obesity

Obesity remains a major worldwide health problem, with current medical treatments being poorly effective. Nutrient sensing allows organs such as the GI tract and the brain to recognize and respond to fuel substrates such as carbohydrates, protein and fats. Specialized neural and hormonal pathways exist to facilitate and regulate these chemosensory mechanisms. Manipulation of factors involved in either central or peripheral chemosensory pathways may provide possible targets for the manipulation of appetite. However, further research is required to assess the utility of this approach to developing novel anti-obesity agents.

Dieting and food craving. A descriptive, quasi-prospective study

Evidence linking food restriction and food craving is equivocal. This study investigated whether dieting was associated with a greater frequency of food craving. Dieting to lose weight was distinguished from watching so as not to gain weight. Participants were 129 women (mean age=41 yrs): 52 were currently dieting to lose weight, 40 were watching their weight, and 37 were non-dieters. They completed a food craving record after every food craving, a food diary, and a daily mood assessment over 7-days. Of the 393 craving incidents recorded, dieters experienced significantly more food cravings than non-dieters, with watchers intermediate. Chocolate was the most craved food (37% of cravings) but neither the types of food, the proportion of cravings leading to eating (∼70%), the situations in which cravings occurred, nor the time since the last eating episode differed between groups. Compared with non-dieters, dieters experienced stronger cravings that were more difficult to resist, and for foods they were restricting eating. Watchers showed similarities in experience both to dieters (low hunger) and non-dieters (lower craving intensity). These results support an association between dieting and food craving, the usefulness of distinguishing dieting to lose weight and watching, and suggest a need for further experimental investigation of actual food restriction on food craving experiences.

Effects of bariatric surgery on food cravings: do food cravings and the consumption of craved foods "normalize" after surgery?

BACKGROUND

The reported effects of bariatric surgery on food cravings have been inconsistent. Moreover, research has been largely limited to sweet cravings, and no study has examined whether surgery patients' cravings differ from those of normal weight (NW) controls. Our objective was to use an empirically validated instrument to examine changes in bariatric surgery patients' frequency of food cravings and consumption of craved foods from before to 3 and 6 months after surgery and to compare surgery patients' frequency of food cravings to those of NW controls. The setting was private hospitals and research center in the United States.

METHODS

Bariatric surgery patients (n = 32) and NW controls (n = 20) completed the Food Cravings Inventory and had their height and weight measured.

RESULTS

Before surgery, the patients reported more overall cravings and cravings for high fat and fast foods and a greater consumption of craved high-fat foods than the NW controls. From before to 3 and 6 months after surgery, the patients had significant reductions in overall cravings for, and consumption of, craved foods, with specific effects for sweets and fast food; however, surgery had virtually no effect on the cravings for high-fat foods. Moreover, high-fat and fast food cravings did not reduce to normative levels. The postoperative patients were less likely to consume craved sweets than NW controls, and the patients' postoperative weight loss was largely unrelated to food cravings.

CONCLUSION

Bariatric surgery is associated with significant reductions in food cravings and consumption of craved foods, with the exception of high-fat foods. Despite these decreases, patients' cravings do not fully reduce to "normative" levels and are not associated with postoperative weight loss.

Evaluation of the French version of the Orientation Towards Chocolate Questionnaire: chocolate-related guilt and ambivalence are associated with overweight and disordered eating

The aims of this study were firstly to evaluate the psychometric properties of the French version of the Orientation towards Chocolate Questionnaire (OCQ), secondly to examine differences in chocolate craving as a function of weight status, and thirdly to examine the OCQ craving dimensions as predictors of body dissatisfaction and disordered eating. Participants included 247 female students from the University of Toulouse, France, who completed measures of chocolate craving, body dissatisfaction, bulimia, drive for thinness, and emotional eating, and for whom body mass index (BMI) was available. Confirmatory factor analysis supported the three-factor model of the OCQ, with guilt, approach, and avoidance subscales. Patterns of endorsement of chocolate craving dimensions differed according to weight status, with ambivalence present only amongst overweight participants. Guilt and approach were positively associated with disordered eating, whereas avoidance was negatively associated with bulimia. These results confirm the validity and reliability of the French version of the OCQ and highlight strong associations between chocolate craving dimensions and disordered eating patterns.

Natural rewards, neuroplasticity, and non-drug addictions

There is a high degree of overlap between brain regions involved in processing natural rewards and drugs of abuse. "Non-drug" or "behavioral" addictions have become increasingly documented in the clinic, and pathologies include compulsive activities such as shopping, eating, exercising, sexual behavior, and gambling. Like drug addiction, non-drug addictions manifest in symptoms including craving, impaired control over the behavior, tolerance, withdrawal, and high rates of relapse. These alterations in behavior suggest that plasticity may be occurring in brain regions associated with drug addiction. In this review, I summarize data demonstrating that exposure to non-drug rewards can alter neural plasticity in regions of the brain that are affected by drugs of abuse. Research suggests that there are several similarities between neuroplasticity induced by natural and drug rewards and that, depending on the reward, repeated exposure to natural rewards might induce neuroplasticity that either promotes or counteracts addictive behavior.

Change in food cravings, food preferences, and appetite during a low-carbohydrate and low-fat diet

The study objective was to evaluate the effect of prescribing a low-carbohydrate diet (LCD) and a low-fat diet (LFD) on food cravings, food preferences, and appetite. Obese adults were randomly assigned to a LCD (n = 134) or a LFD (n = 136) for 2 years. Cravings for specific types of foods (sweets, high-fats, fast-food fats, and carbohydrates/starches); preferences for high-sugar, high-carbohydrate, and low-carbohydrate/high-protein foods; and appetite were measured during the trial and evaluated during this secondary analysis of trial data. Differences between the LCD and LFD on change in outcome variables were examined with mixed linear models. Compared to the LFD, the LCD had significantly larger decreases in cravings for carbohydrates/starches and preferences for high-carbohydrate and high-sugar foods. The LCD group reported being less bothered by hunger compared to the LFD group. Compared to the LCD group, the LFD group had significantly larger decreases in cravings for high-fat foods and preference for low-carbohydrate/high-protein foods. Men had larger decreases in appetite ratings compared to women. Prescription of diets that promoted restriction of specific types of foods resulted in decreased cravings and preferences for the foods that were targeted for restriction. The results also indicate that the LCD group was less bothered by hunger compared to the LFD group and that men had larger reductions in appetite compared to women.

Experimental effects of chocolate deprivation on cravings, mood, and consumption in high and low chocolate-cravers

This study examined how deprivation of chocolate affects state-level chocolate cravings, mood, and chocolate consumption in high and low trait-level chocolate-cravers. After identifying high and low chocolate cravers (N=58), half of the participants were instructed not to eat any chocolate for 2weeks. This created four experimental groups: deprived high-cravers (n=14), deprived low-cravers (n=14), non-deprived high-cravers (n=15), and non-deprived low-cravers (n=15). Following 2-week deprivation, state-level food cravings, mood, and chocolate intake were measured in a laboratory setting and compared across groups. Analyses revealed that anxiety increased over time for high-cravers (both deprived and non-deprived); state-level chocolate- and food-craving increased over time for both deprived groups and non-deprived high-cravers; non-deprived high-cravers ate the most chocolate; and, high-cravers were more joyful and guilty than low-cravers after eating chocolate in the laboratory. Theoretically, these results suggest that chocolate consumption may be better explained by trait-level of chocolate craving than by deprivation and highlighted significant differences in mood, state-level cravings, and chocolate intake between cravers and non-cravers following deprivation.

The temporal dynamics of ambivalence: changes in positive and negative affect in relation to consumption of an "emotionally charged" food

Ambivalence is thought to impact consumption of food, alcohol and drugs, possibly via influences on craving, with cravers often being simultaneously drawn toward and repelled from ingestion. So far, little is known about the temporal dynamics of ambivalence, especially as it varies in relationship to consumption. Participants (n=482, 56.8% female) completed the Positive and Negative Affect Schedule prior to, immediately and 30 min after the opportunity to eat a bar of chocolate. Affective ambivalence was calculated based on the relative strengths of and discrepancy between ratings of positive and negative affect. Ambivalence peaked prior to a decision about consumption and subsequently decreased, whether or not the decision was in favor of or against consuming. Decreasing ambivalence was driven by a drop in positive affect over time; positivity decreased more rapidly in those who consumed chocolate. Findings represent a first step in characterizing the dynamics of ambivalence in interactions with a target stimulus.

Food reward, hyperphagia, and obesity

Given the unabated obesity problem, there is increasing appreciation of expressions like "my eyes are bigger than my stomach," and recent studies in rodents and humans suggest that dysregulated brain reward pathways may be contributing not only to drug addiction but also to increased intake of palatable foods and ultimately obesity. After describing recent progress in revealing the neural pathways and mechanisms underlying food reward and the attribution of incentive salience by internal state signals, we analyze the potentially circular relationship between palatable food intake, hyperphagia, and obesity. Are there preexisting individual differences in reward functions at an early age, and could they be responsible for development of obesity later in life? Does repeated exposure to palatable foods set off a cascade of sensitization as in drug and alcohol addiction? Are reward functions altered by secondary effects of the obese state, such as increased signaling through inflammatory, oxidative, and mitochondrial stress pathways? Answering these questions will significantly impact prevention and treatment of obesity and its ensuing comorbidities as well as eating disorders and drug and alcohol addiction.

A multimodal approach to assessing the impact of nicotine dependence, nicotine abstinence, and craving on negative affect in smokers

We used multimodal measurement to evaluate whether (a) nicotine dependence is associated with baseline and postquit negative affect and craving, (b) smoking relapse is associated with greater negative affect and craving than abstinence, and (c) craving is associated with negative affect. Treatment-seeking smokers were randomly assigned to either a brief behaviorally based smoking-cessation treatment condition or to a delayed treatment control condition. Participants in the treatment condition attended four assessment sessions, 4-5 days prequit (baseline), 1-2 days postquit, 3-5 days postquit, and 10-14 days postquit, while controls attended four sessions spaced over the same intervals. Retrospective questionnaires were collected at the beginning of each session, and corrugator EMG and in-session ratings were collected during viewing of affective and cigarette-related slides. The multimodal measures indicated that more dependent smokers experienced greater negative affect and craving at baseline and postquit, regardless of abstinence status. The self-report measures indicated that both relapsed and abstinent smokers reported greater negative affect and craving than control smokers. Craving was associated with negative affect across measurement modalities. These results highlight the benefits of using multimodal measures to study the impact of nicotine dependence and withdrawal on negative affect and craving.

Central dopaminergic circuitry controlling food intake and reward: implications for the regulation of obesity

Prevalence of obesity in the general population has increased in the past 15 years from 15% to 35%. With increasing obesity, the coincident medical and social consequences are becoming more alarming. Control over food intake is crucial for the maintenance of body weight and represents an important target for the treatment of obesity. Central nervous system mechanisms responsible for control of food intake have evolved to sense the nutrient and energy levels in the organism and to coordinate appropriate responses to adjust energy intake and expenditure. This homeostatic system is crucial for maintenance of stable body weight over long periods of time of uneven energy availability. However, not only the caloric and nutritional value of food but also hedonic and emotional aspects of feeding affect food intake. In modern society, the increased availability of highly palatable and rewarding (fat, sweet) food can significantly affect homeostatic balance, resulting in dysregulated food intake. This review will focus on the role of hypothalamic and mesolimbic/mesocortical dopaminergic (DA) circuitry in coding homeostatic and hedonic signals for the regulation of food intake and maintenance of caloric balance. The interaction of dopamine with peripheral and central indices of nutritional status (e.g., leptin, ghrelin, neuropeptide Y), and the susceptibility of the dopamine system to prenatal insults will be discussed. Additionally, the importance of alterations in dopamine signaling that occur coincidently with obesity will be addressed.

Theobromine and the pharmacology of cocoa

The effects of theobromine in man are underresearched, possibly owing to the assumption that it is behaviourally inert. Toxicology research in animals may appear to provide alarming results, but these cannot be extrapolated to humans for a number of reasons. Domestic animals and animals used for racing competitions need to be guarded from chocolate and cocoa-containing foods, including foods containing cocoa husks. Research ought to include caffeine as a comparative agent, and underlying mechanisms need to be further explored. Of all constituents proposed to play a role in our liking for chocolate, caffeine is the most convincing, though a role for theobromine cannot be ruled out. Most other substances are unlikely to exude a psychopharmacological effect owing to extremely low concentrations or the inability to reach the blood-brain barrier, whilst chocolate craving and addiction need to be explained by means of a culturally determined ambivalence towards chocolate.

Cocaine is low on the value ladder of rats: possible evidence for resilience to addiction

Background

Assessing the relative value of cocaine and how it changes with chronic drug use represents a long-standing goal in addiction research. Surprisingly, recent experiments in rats – by far the most frequently used animal model in this field – suggest that the value of cocaine is lower than previously thought.

Methodology/Principal Findings

Here we report a series of choice experiments that better define the relative position of cocaine on the value ladder of rats (i.e., preference rank-ordering of different rewards). Rats were allowed to choose either taking cocaine or drinking water sweetened with saccharin – a nondrug alternative that is not biologically essential. By systematically varying the cost and concentration of sweet water, we found that cocaine is low on the value ladder of the large majority of rats, near the lowest concentrations of sweet water. In addition, a retrospective analysis of all experiments over the past 5 years revealed that no matter how heavy was past cocaine use most rats readily give up cocaine use in favor of the nondrug alternative. Only a minority, fewer than 15% at the heaviest level of past cocaine use, continued to take cocaine, even when hungry and offered a natural sugar that could relieve their need of calories.

Conclusions/Significance

This pattern of results (cocaine abstinence in most rats; cocaine preference in few rats) maps well onto the epidemiology of human cocaine addiction and suggests that only a minority of rats would be vulnerable to cocaine addiction while the large majority would be resilient despite extensive drug use. Resilience to drug addiction has long been suspected in humans but could not be firmly established, mostly because it is difficult to control retrospectively for differences in drug self-exposure and/or availability in human drug users. This conclusion has important implications for preclinical research on the neurobiology of cocaine addiction and for future medication development.

What neurobiology cannot tell us about addiction

Molecular neurobiological studies have yielded enormous amounts of valuable information about neuronal response mechanisms and their adaptive changes. However, in relation to addiction this information is of limited value because almost every cell function appears to be involved. Thus it tells us only that neurons adapt to 'addictive drugs' as they do to all sorts of other functional disturbances. This information may be of limited help in the development of potential auxiliary agents for treatment of addiction. However, a reductionist approach which attempts to analyse addiction at ever finer levels of structure and function, is inherently incapable of explaining what causes these mechanisms to be brought into play in some cases and not in others, or by self-administration of a drug but not by passive exposure. There is abundant evidence that psychological, social, economic and specific situational factors play important roles in initiating addiction, in addition to genetic and other biological factors. Therefore, if we hope to be able to make predictions at any but a statistical level, or to develop effective means of prevention, it is necessary to devise appropriate integrative approaches to the study of addiction, rather than pursue an ever-finer reductive approach which leads steadily farther away from the complex interaction of drug, user, environment and specific situations that characterizes the problem in humans.

Does "craving" carve nature at the joints? Absence of a synonym for craving in many languages

INTRODUCTION

Craving is a term commonly used by North American lay people, and is also used as an important category in psychological and addiction research. However, difficulties in defining craving suggest that it may not be a natural category.

METHODS

Assuming that lexicalization of a concept is an indicator of its importance and/or universality, the presence of synonyms for craving is examined in a range of natural languages, using both dictionaries and native speaker informants. Related words, such as "love," "like," "urge," "desire," "adore" and "addiction" are also explored in 20 languages, in terms of meaning and the domains of life to which these words are applied.

RESULTS

Based on automated translations, 64% of 25 languages have a craving synonym, and based on native speaker, only 17% of 20 languages lexicalize craving; when there is a synonym, it seems to mean a desire for a potential ingestant or a drug, that is, it is a desire restricted to certain domains of activity.

DISCUSSION

The concept of "craving" appears to be limited in its importance and relevance in languages and cultures outside of English and North America. This finding has important implications for the understanding of "craving" as a natural category in the study of drug and other addictions. A similar though less extensive lack of synonyms for "addiction" is also reported.

Does dark chocolate have a role in the prevention and management of hypertension?: commentary on the evidence

The notion that eating chocolate would prevent or treat hypertension is appealing to many who produce and enjoy chocolate. Several studies have documented beneficial effects of dark chocolate on insulin action and endothelial function. However, the published studies on chocolate and blood pressure include a relatively small number of subjects, and results are conflicting. In addition, because of secrecy surrounding the production of chocolate and the unique sociocultural context of this popular food, research on efficacy and effectiveness is complex. This commentary summarizes 13 peer-reviewed studies on dark chocolate and blood pressure and raises questions relevant to its future as an evidence-based lifestyle intervention.

The tempted brain eats: pleasure and desire circuits in obesity and eating disorders

What we eat, when and how much, all are influenced by brain reward mechanisms that generate "liking" and "wanting" for foods. As a corollary, dysfunction in reward circuits might contribute to the recent rise of obesity and eating disorders. Here we assess brain mechanisms known to generate "liking" and "wanting" for foods and evaluate their interaction with regulatory mechanisms of hunger and satiety, relevant to clinical issues. "Liking" mechanisms include hedonic circuits that connect together cubic-millimeter hotspots in forebrain limbic structures such as nucleus accumbens and ventral pallidum (where opioid/endocannabinoid/orexin signals can amplify sensory pleasure). "Wanting" mechanisms include larger opioid networks in nucleus accumbens, striatum, and amygdala that extend beyond the hedonic hotspots, as well as mesolimbic dopamine systems, and corticolimbic glutamate signals that interact with those systems. We focus on ways in which these brain reward circuits might participate in obesity or in eating disorders.

Chronic suppression of μ-opioid receptor signaling in the nucleus accumbens attenuates development of diet-induced obesity in rats

Objective

To test the hypothesis that mu-opioid receptor signaling in the nucleus accumbens contributes to hedonic (over)eating and obesity. To investigate the effects of chronic mu-opioid antagonism in the nucleus accumbens core or shell on intake of a palatable diet, and the development of diet-induced obesity in rats.

Methods and Design

Chronic blockade of mu-opioid receptor-signaling in the nucleus accumbens core or shell was achieved by means of repeated injections (every 4–5 days) of the irreversible receptor antagonist β-Funaltrexamine (BFNA) over 3–5 weeks. The diet consisted of either a choice of high-fat chow, chocolate-flavored Ensure, and regular chow (each nutritionally complete), or regular chow only. Intake of each food item, body weight, and body fat mass were monitored throughout the study.

Results

BFNA injections aimed at either the core or shell of the nucleus accumbens resulted in significantly attenuated intake of palatable diet, body weight gain, and fat accretion, compared with vehicle control injections. BFNA in the core did not significantly change these parameters in chow-fed control rats. BFNA in the core and shell differentially affected intake of the two palatable food items: in the core BFNA significantly reduced intake of high-fat, but not of Ensure, whereas in the shell, it significantly reduced intake of Ensure, but not of high-fat, compared with vehicle-treatment.

Conclusions

Endogenous mu-opioid receptor-signaling in the nucleus accumbens core and shell is necessary for palatable diet-induced hyperphagia and obesity to fully develop in rats. Sweet and non-sweet fatty foods may be differentially processed in subcomponents of the ventral striatum.

The plausibility of sugar addiction and its role in obesity and eating disorders

BACKGROUND & AIMS

To consider the hypothesis that addiction to food, or more specifically sucrose, plays a role in obesity and eating disorders.

METHODS

By considering the relevant literature a series of predictions were examined, derived from the hypothesis that addiction to sucrose consumption can develop. Fasting should increase food cravings, predominantly for sweet items; cravings should occur after an overnight fast; the obese should find sweetness particularly attractive; a high-sugar consumption should predispose to obesity. More specifically predictions based on the hypothesis that addiction to sugar is central to bingeing disorders were developed. Dieting should predate the development of bingeing; dietary style rather than psychological, social and economic factors should be predispose to eating disorders; sweet items should be preferentially consumed while bingeing; opioid antagonists should cause withdrawal symptoms; bingeing should develop at a younger age when there is a greater preference for sweetness.

RESULTS

The above predications have in common that on no occasion was the behaviour predicted by an animal model of sucrose addiction supported by human studies.

CONCLUSION

There is no support from the human literature for the hypothesis that sucrose may be physically addictive or that addiction to sugar plays a role in eating disorders.

State craving, food availability, and reactivity to preferred snack foods

The startle response has been shown to be useful in studying reactivity to food cues. Following 6h of food deprivation and exposure to neutral and food cues, we examined the role of state craving combined with both a short and long delay of consumption on affect and startle reflex. Participants completed the PANAS, consumed a controlled early morning meal, and experienced 6h of food deprivation. They then reported back to the laboratory, completed a second baseline PANAS, and had their baseline eyeblink EMG startle responses to 100 dB(A) startle probe assessed. Prior to and following the presentation of cues, startle probes were presented and responses were recorded. The PANAS and state craving were also assessed after each cue. Food cues provoked higher levels of state craving than neutral cues and startle responses failed to habituate as quickly to food cues as they did to neutral cues. In addition, cue exposure created the highest NA among high state cravers in the long delay of consumption group. Startle responses differed from NA in that with long delay startle was high irrespective of state craving scores; in the short delay of consumption condition, startle increased linearly with state craving. These results illustrate that state craving and expectations of food availability are important variables in understanding food-related cue reactivity.

Pre-exposure to environmental cues predictive of food availability elicits hypothalamic-pituitary-adrenal axis activation and increases operant responding for food in female rats

The present study was undertaken to develop an animal model exploiting food cue-induced increased motivation to obtain food under operant self-administration conditions. To demonstrate the predictive validity of the model, rimonabant, fluoxetine, sibutramine and topiramate, administered 1 hour before the experiment, were tested. For 5 days, female Wistar rats were trained to self-administer standard 45 mg food pellets in one daily session (30 minutes) under FR1 (fixed ratio 1) schedule of reinforcement. Rats were then trained to an FR3 schedule and finally divided into two groups. The first group (control) was subjected to a standard 30 minutes FR3 food self-administration session. The second group was exposed to five presentations of levers and light for 10 seconds each (every 3 minutes in 15 minutes total). At the completion of this pre-session phase, a normal 30-minute session (as in the control group) started. Results showed that pre-exposure to environmental stimuli associated to food deliveries increased response for food when the session started. Corticosterone and adrenocorticotropic hormone plasma levels, measured after the 15-minute pre-exposure, were also significantly increased. No changes were observed for the other measured hormones (growth hormone, prolactin, thyroid-stimulating hormone, luteinizing hormone, insulin, amylin, gastric inhibitor polypeptide, ghrelin, leptin, peptide YY and pancreatic polypeptide). Rimonabant, sibutramine and fluoxetine significantly reduced food intake in both animals pre-exposed and in those not pre-exposed to food-associated cues. Topiramate selectively reduced feeding only in pre-exposed rats. The present study describes the development of a new animal model to investigate cue-induced increased motivation to obtain food. This model shows face and predictive validity, thus, supporting its usefulness in the investigation of new potential treatments of binge-related eating disorders. In addition, the present findings confirm that topiramate may represent an important pharmacotherapeutic approach to binge-related eating.

Cultural values and political economic contexts of diabetes among low-income Mexican Americans

PURPOSE

To explore the political and economic dimensions of diabetes self-management for Mexican American adults.

DESIGN

Critical ethnographic analysis of focus group data from caregivers and adults with diabetes.

FINDINGS

Three themes were identified: diabetes self-management is tied to other mental and bodily states, family and neighborhood environments cause stress and prevent diabetes solutions, and hassles of the health care environment subvert self-management.

DISCUSSION

Cultural constructs about diabetes merge with social-political forces in explaining diabetes.

IMPLICATIONS

Cultural competence in diabetes care requires attention to the political economy of the disease and advocacy for healthful political and economic change.

Chocolate, lifestyle, and health

Interest in the biological activities of cocoa polyphenols is increasing steadily. In fact, the high polyphenol content of cocoa, coupled with its widespread presence in many food items, render this food of particular interest from the nutritional and "pharmacological" viewpoints. This paper summarizes the new findings and developments regarding the effects of cocoa and chocolate consumption on human health as presented at the International Conference "Chocolate, Lifestyle, and Health" (Milan, Italy, March 2, 2007) regarding the effects of cocoa and chocolate consumption on human health.

The feeling of being trapped in and ashamed of one's own body: A qualitative study of women who suffer from eating difficulties

The aim of this study was to explore women's bodily experiences of suffering from eating difficulties (ED). The research question was: How do women who suffer from ED experience the bodily aspects related to their condition? Women suffering from ED experience problems in both the physical and emotional areas. Few qualitative studies have specifically addressed sufferers' bodily experiences related to ED. An explorative design was used. The data were collected by means of focus group interviews on the subject of ED-related problems, guilt and shame, and being a mother. The interpretation of the qualitative data was inspired by hermeneutic content analysis. The main theme, 'Powerful feelings of being trapped in and ashamed of one's own body', comprised two themes: 'The feeling of being trapped by overwhelming physical sensations' and 'The feeling of being ashamed of one's own body'. Bodily experiences were reported as strong. One clinical implication for nurses is to acknowledge this fact and make it possible for these women to articulate their difficulties, especially those connected to the feelings of being trapped and ashamed. Support groups focusing on these themes could be one way of assisting women and easing some of the negative feelings associated with ED.

'Liking' and 'wanting' food rewards: brain substrates and roles in eating disorders

What brain reward systems mediate motivational 'wanting' and hedonic 'liking' for food rewards? And what roles do those systems play in eating disorders? This article surveys recent findings regarding brain mechanisms of hedonic 'liking', such as the existence of cubic-millimeter hedonic hotspots in nucleus accumbens and ventral pallidum for opioid amplification of sensory pleasure. It also considers brain 'wanting' or incentive salience systems important to appetite, such as mesolimbic dopamine systems and opioid motivation circuits that extend beyond the hedonic hotspots. Finally, it considers some potential ways in which 'wanting' and 'liking' might relate to eating disorders.

Homeostatic and hedonic signals interact in the regulation of food intake

Food intake is regulated by 2 complementary drives: the homeostatic and hedonic pathways. The homeostatic pathway controls energy balance by increasing the motivation to eat following depletion of energy stores. In contrast, hedonic or reward-based regulation can override the homeostatic pathway during periods of relative energy abundance by increasing the desire to consume foods that are highly palatable. In contrast to the consumption of food, the motivation to use drugs of abuse is mediated only by the reward pathway. In this article we review the extensive research that has identified several mechanisms by which repeated exposure to drugs of abuse alters neuronal function and increases the motivational incentive to obtain and use these substances. We then compare our current understanding of drug-induced changes in neuronal reward circuitry with what is known about the consequences of repeated consumption of highly palatable foods such as high-fat and high-sugar diets. Next, we discuss the normal homeostatic regulation of food intake, which is a unique aspect of food addiction. Finally, we discuss the clinical implications of these neuronal adaptations in the context of obesity and neuropsychiatric syndromes such as bulimia nervosa and Prader-Willi syndrome.

Cognitive-motivational determinants of fat food consumption in overweight and obese youngsters: the implicit association between fat food and arousal

Cognitive-motivational accounts of fat food intake propose an association between fat food and action dispositions, which are according to the biphasic emotion theory of Lang [(1995). The emotion probe. Studies of motivation and attention. American Psychologist, 50, 372-385; Lang, P.J., Bradley, M.M., & Cuthbert, M.M. (1997). Motivated attention: Affect, activation and action. In P.J. Lang, R.F. Simons & M.T. Balaban (Eds.). Attention and orienting: Sensory and motivational processes (pp. 97-134). Hillsdale, NJ: Lawrence Erlbaum Associates, Inc.] characterized by high levels of arousal. In two experiments, this association was investigated in lean and overweight youngsters. In the first experiment, 29 overweight and 29 lean youngsters conducted two Implicit Association Tasks (IAT; Greenwald, A.G., McGhee, D.E., & Schwartz, J.L. (1998). Measuring individual differences in implicit cognition: The implicit association test. Journal of Personality and Social Psychology, 74, 1464-1480.). In a positive arousal IAT, implicit associations between fat vs. lean food, and high and low arousal words with a positive valence were assessed. In a negative arousal IAT, high and low arousal words with a negative valence were used. A second experiment was conducted to replicate Experiment 1 in 29 youngsters with severe obesity and 29 lean peers. The results revealed strong implicit associations between fat food and arousal in both the overweight and the control group. No differences were found between the groups, nor between the positive and the negative arousal task. These results are related to cognitive-motivational theories of fat food intake.

Abuse potential of carbohydrates for overweight carbohydrate cravers

RATIONALE

The long-rejected construct of food addiction is undergoing re-examination.

OBJECTIVES

To evaluate whether a novel carbohydrate food shows abuse potential for rigorously defined carbohydrate cravers, as evidenced by selective self-administration and mood enhancement during double-blind discrimination testing.

MATERIALS AND METHODS

Discrete trials choice testing was performed with 61 overweight (BMI m = 27.64, SD = 2.59) women (ages 18-45; 19.70% African American) whose diet records showed >4 weekly afternoon/evening emotional-eating episodes confined to snacks with carbohydrate to protein ratio of >6:1. After being induced into a sad mood, participants were exposed, double-blind and in counterbalanced order, to taste-matched carbohydrate and protein beverages. They were asked to choose and self-administer the drink that made them feel better.

RESULTS

Women overwhelmingly chose the carbohydrate beverage, even though blinded. Mixed-effects regression modeling, controlling for beverage order, revealed greater liking and greater reduction in dysphoria after administration of the carbohydrate beverage compared to the protein beverage but no differential effect on vigor.

CONCLUSION

For women who crave them, carbohydrates appear to display abuse potential, plausibly contributing to overconsumption and overweight.

Alteration of eating behaviors in patients with Parkinson's disease: possibly overlooked?

Patients with Parkinson's disease (PD) occasionally show food cravings and/or compulsive eating that result in significant, undesired weight gain. Dopamine replacement therapy may be the cause of this type of eating disorder. We evaluated 60 consecutive patients to see if they had any alteration of eating patterns after starting levodopa. Among them, five (8.3%) patients exhibited characteristic alterations of food preference following the start of dopamine replacement therapy. One patient showed an undesirable weight gain. Of the five patients exhibiting food preference alterations, all showed increased preference to consume sweet snacks, although this alteration was not always associated with hyperphagia (eating too much). This type of dietary alteration was not related to a specific antiparkinsonian drug, and could be observed in patients undergoing dopamine agonist monotherapy. Alteration of eating behavior may not be uncommon in PD patients, and is possibly overlooked. Since dopamine is closely involved in acquisition of food preferences, dietary changes with/without compulsive eating may be a manifestation of an alteration of appetitive behaviors due to excessive dopaminergic neurotransmission.

Repeated cue exposure effects on subjective and physiological indices of chocolate craving

The aim of this study is to investigate the effects of repeated unreinforced exposure to chocolate cues in persons reporting chocolate craving. Participants in the experimental group (n=40) received 10 consecutive brief exposures to chocolate cues in each of two sessions, separated by 1-3 days. Control participants (n=18) received two exposures at the start and end of each session. Chocolate craving was measured (alternately) through subjective report and the amount of saliva secretion to chocolate cues. Results showed a between-sessions decrease in both craving measures in the experimental group, whereas no differences in craving between sessions were observed in the control group. These results provide evidence for the effects of cue exposure treatment in chocolate craving.