Stress-induced laboratory eating behavior in obese women with binge eating disorder

Lifetime stressor exposure is associated with greater rewarding effects of stress-related eating

Acute stressors tend to shift preferences toward comfort foods, yet they do not ubiquitously increase the amount of food consumed. Moreover, although many individuals eat more under stress, others eat less or show no change. Although the precise mechanisms explaining this variability in stress-related eating are unknown, they may be driven by individual differences in the rewarding effects of comfort eating, which are enhanced by greater lifetime stressor exposure. To investigate this possibility, we examined whether differences in lifetime stressor exposure predicted reductions in negative affect following snacking (i.e., negative reinforcement) and if this effect was specific to stress-related snacking or snacking in general. Participants were 26 women (23% non-White) between 20 and 45 years old (M = 31), with a mean body mass index of 26, who completed three laboratory visits. Participants completed an assessment of lifetime stressor exposure (i.e., STRAIN) on the first visit and, on two subsequent laboratory visits in counterbalanced order, were given snacks after an acute social stress task (i.e., TSST) or rest period. Greater lifetime stressor exposure was related to greater post-ingestive decreases in negative affect following the acute social stressor but not following the rest period. If stress-related eating is more comforting for women with greater lifetime stressors and contributes to a stronger stress-eating association, then this may inform obesity-related clinical treatments that target behaviors and cognitions related to reward-based learning.

The influence of stress on the neural underpinnings of disinhibited eating: a systematic review and future directions for research

Disinhibited eating involves overconsumption and loss of control over food intake, and underpins many health conditions, including obesity and binge-eating related disorders. Stress has been implicated in the development and maintenance of disinhibited eating behaviours, but the mechanisms underlying this relationship are unclear. In this systematic review, we examined how the impact of stress on the neurobiological substrates of food-related reward sensitivity, interoception and cognitive control explains its role in disinhibited eating behaviours. We synthesised the findings of functional magnetic resonance imaging studies including acute and/or chronic stress exposures in participants with disinhibited eating. A systematic search of existing literature conducted in alignment with the PRISMA guidelines identified seven studies investigating neural impacts of stress in people with disinhibited eating. Five studies used food-cue reactivity tasks, one study used a social evaluation task, and one used an instrumental learning task to probe reward, interoception and control circuitry. Acute stress was associated with deactivation of regions in the prefrontal cortex implicated in cognitive control and the hippocampus. However, there were mixed findings regarding differences in reward-related circuitry. In the study using a social task, acute stress associated with deactivation of prefrontal cognitive control regions in response to negative social evaluation. In contrast, chronic stress was associated with both deactivation of reward and prefrontal regions when viewing palatable food-cues. Given the small number of identified publications and notable heterogeneity in study designs, we propose several recommendations to strengthen future research in this emerging field.

Validation of computational models to characterize cumulative intake curves from video-coded meals

Introduction

Observational coding of eating behaviors (e.g., bites, eating rate) captures behavioral characteristics but is limited in its ability to capture dynamic patterns (e.g., temporal changes) across a meal. While the Universal Eating Monitor captures dynamic patterns of eating through cumulative intake curves, it is not commonly used in children due to strict behavioral protocols. Therefore, the objective of this study was to test the ability of computational models to characterize cumulative intake curves from video-coded meals without the use of continuous meal weight measurement.

Methods

Cumulative intake curves were estimated using Kisslieff's Quadratic model and Thomas's logistic ordinary differential equation (LODE) model. To test if cumulative intake curves could be characterized from video-coded meals, three different types of data were simulated: (1) Constant Bite: simplified cumulative intake data; (2) Variable Bite: continuously measured meal weight data; and (3) Bite Measurement Error: video-coded meals that require the use of average bite size rather than measured bite size.

Results

Performance did not differ by condition, which was assessed by examining model parameter recovery, goodness of fit, and prediction error. Therefore, the additional error incurred by using average bite size as one would with video-coded meals did not impact the ability to accurately estimate cumulative intake curves. While the Quadratic and LODE models were comparable in their ability to characterize cumulative intake curves, the LODE model parameters were more distinct than the Quadradic model. Greater distinctness suggests the LODE model may be more sensitive to individual differences in cumulative intake curves.

Discussion

Characterizing cumulative intake curves from video-coded meals expands our ability to capture dynamic patterns of eating behaviors in populations that are less amenable to strict protocols such as children and individuals with disordered eating. This will improve our ability to identify patterns of eating behavior associated with overconsumption and provide new opportunities for treatment.

Is work-family conflict a pathway between job strain components and binge eating? A cross-sectional analysis from the ELSA-Brasil study

BACKGROUND

Job strain has been reported as a trigger for binge eating, yet the underlying mechanisms have been unclear. The aim of this study was to evaluate whether work-family conflict is a pathway in the association between job strain and binge eating, considering the possible effect-modifying influence of body mass index (BMI).

METHODS

This cross-sectional analysis included 12,084 active civil servants from the multicenter Brazilian Longitudinal Study of Adult Health (ELSA-Brasil). Job strain was assessed using the Demand-Control-Support Questionnaire. Work-family conflict was considered as a latent variable comprising three items. Binge eating was defined as eating a large amount of food in less than 2 h at least twice a week in the last six months with a sense of lack of control over what and how much was eaten. Structural equation modelling was used to test the role of work-family conflict in the association between job strain and binge eating, stratifying for BMI.

RESULTS

For individuals of normal weight, positive associations were found between skill discretion and binge eating (standardized coefficient [SC] = 0.209, 95%CI = 0.022-0.396), and between psychological job demands and work-family conflict (SC = 0.571, 95%CI = 0.520-0.622), but no statistically significant indirect effect was found. In overweight individuals, psychological job demands, skill discretion, and work-family conflict were positively associated with binge eating (SC = 0.099, 95%CI = 0.005-0.193; SC = 0.175, 95%CI = 0.062-0.288; and SC = 0.141, 95%CI = 0.077-0.206, respectively). Also, work-family conflict was observed to be a pathway on the associations of psychological job demands and decision authority with binge eating (SC = 0.084, 95%CI = 0.045-0.122; and SC =  - 0.008, 95%CI =  - 0.015- - 0.001, respectively).

CONCLUSIONS

Work-family conflict partly explains effects of high levels of psychological job demands and low levels of decision authority on binge eating among overweight individuals. Moreover, skill discretion is positively associated with binge eating, regardless of BMI category.

Volume and Connectivity Differences in Brain Networks Associated with Cognitive Constructs of Binge Eating

Bulimia nervosa (BN) and binge eating disorder (BED) are characterized by episodes of eating large amounts of food while experiencing a loss of control. Recent studies suggest that the underlying causes of BN/BED consist of a complex system of environmental cues, atypical processing of food stimuli, altered behavioral responding, and structural/functional brain differences compared with healthy controls (HC). In this narrative review, we provide an integrative account of the brain networks associated with the three cognitive constructs most integral to BN and BED, namely increased reward sensitivity, decreased cognitive control, and altered negative affect and stress responding. We show altered activity in BED/BN within several brain networks, specifically in the striatum, insula, prefrontal cortex (PFC) and orbitofrontal cortex (OFC), and cingulate gyrus. Numerous key nodes in these networks also differ in volume and connectivity compared with HC. We provide suggestions for how this integration may guide future research into these brain networks and cognitive constructs.

Chronic Restraint Stress Decreases the Excitability of Hypothalamic POMC Neuron and Increases Food Intake

Stress activates the hypothalamic-pituitary-adrenal system, and induces the release of glucocorticoids, stress hormones, into circulation. Many studies have shown that stress affects feeding behavior, however, the underlying circuitry and molecular mechanisms are not fully understood. The balance between orexigenic (simulating appetite) and anorexigenic (loss of appetite) signals reciprocally modulate feeding behavior. It is suggested that proopiomelanocortin (POMC) and neuropeptide Y (NPY) neurons in the arcuate nucleus (ARC) of the hypothalamus are the first-order neurons that respond to the circulating signals of hunger and satiety. Here, we examined a chronic restraint stress model and observed an increase in food intake, which was not correlated with anhedonia. We investigated whether stress affects the properties of POMC and NPY neurons and found that chronic restraint stress reduced the excitatory inputs onto POMC neurons and increased the action potential threshold. Therefore, our study suggests that chronic stress modulates the intrinsic excitability and excitatory inputs in POMC neurons, leading to changes in feeding behavior.

Two of a Kind? Mapping the Psychopathological Space between Obesity with and without Binge Eating Disorder

(1) Background: Obesity (OB) is a frequent co-morbidity in Binge Eating Disorder (BED), suggesting that both conditions share phenotypical features along a spectrum of eating-related behaviors. However, the evidence is inconsistent. This study aimed to comprehensively compare OB-BED patients against OB individuals without BED and healthy, normal-weight controls in general psychopathological features, eating-related phenotypes, and early life experiences. (2) Methods: OB-BED patients (n = 37), OB individuals (n = 50), and controls (n = 44) completed a battery of standardized questionnaires. Responses were analyzed using univariate comparisons and dimensionality reduction techniques (linear discriminant analysis, LDA). (3) Results: OB-BED patients showed the highest scores across assessments (e.g., depression, emotional and stress eating, food cravings, food addiction). OB-BED patients did not differ from OB individuals in terms of childhood traumatization or attachment styles. The LDA revealed a two-dimensional solution that distinguished controls from OB and OB-BED in terms of increasing problematic eating behaviors and attitudes, depression, and childhood adversities, as well as OB-BED from OB groups in terms of emotional eating tendencies and self-regulation impairments. (4) Conclusions: Findings support the idea of a shared spectrum of eating-related disorders but also highlight important distinctions relevant to identifying and treating BED in obese patients.

Cortisol Reactivity to a Digital Version of Trier Social Stress Test and Eating Behavior in Non-Overweight and Overweight Adolescents: A Pilot Study

(1) Background: In the present pilot study, we examined the response of cortisol to a digital version of the Trier Social Stress Test (TSST) and corresponding eating preferences in non-overweight and overweight adolescents. (2) Methods: The experimental study group included 35 adolescents aged 15.7 ± 0.5 years (16 boys and 19 girls). The participants were split into two groups: non-overweight (N = 24) and overweight (N = 11), according to the Body Mass Index (BMI). We induced acute stress in all participants, using a digital version of the Trier Social Stress Test (TSST), with three different digital tasks. We measured salivary cortisol before the test (T0), during the stress induction by digital tasks (T5, T10, T15), and 25 min after the stress test (T40). The Health Behavior in School-Aged Children Questionnaire (HBSC) was administered to assess the influence of stress on eating behavior: the consumption of fruit, vegetables, sweets, and soft drinks and the frequency of snacks. (3) Results: Among the entire group of adolescents, we observed a significant difference between the sexes in terms of cortisol response, girls being predominantly hyperreactive (13 girls compared to 5 boys, p = 0.03). In overweight adolescents, the cortisol reactivity was lower in boys and higher in girls (p = 0.05). The overweight hyperreactive adolescents, as compared to the hyporeactive ones, had a higher frequency of daily consumption of sweets (25% vs. 0%) and soft drink (25% vs. 0). (4) Conclusions: The individual patterns of cortisol reactivity to laboratory-induced stress could be associated with an increased risk of unhealthy eating behavior in adolescents.

Cortisol Reactivity to a Digital Version of Trier Social Stress Test and Eating Behavior in Non-Overweight and Overweight Adolescents: A Pilot Study

(1) Background: In the present pilot study, we examined the response of cortisol to a digital version of the Trier Social Stress Test (TSST) and corresponding eating preferences in non-overweight and overweight adolescents. (2) Methods: The experimental study group included 35 adolescents aged 15.7 ± 0.5 years (16 boys and 19 girls). The participants were split into two groups: non-overweight (N = 24) and overweight (N = 11), according to the Body Mass Index (BMI). We induced acute stress in all participants, using a digital version of the Trier Social Stress Test (TSST), with three different digital tasks. We measured salivary cortisol before the test (T0), during the stress induction by digital tasks (T5, T10, T15), and 25 min after the stress test (T40). The Health Behavior in School-Aged Children Questionnaire (HBSC) was administered to assess the influence of stress on eating behavior: the consumption of fruit, vegetables, sweets, and soft drinks and the frequency of snacks. (3) Results: Among the entire group of adolescents, we observed a significant difference between the sexes in terms of cortisol response, girls being predominantly hyperreactive (13 girls compared to 5 boys, p = 0.03). In overweight adolescents, the cortisol reactivity was lower in boys and higher in girls (p = 0.05). The overweight hyperreactive adolescents, as compared to the hyporeactive ones, had a higher frequency of daily consumption of sweets (25% vs. 0%) and soft drink (25% vs. 0). (4) Conclusions: The individual patterns of cortisol reactivity to laboratory-induced stress could be associated with an increased risk of unhealthy eating behavior in adolescents.

Associations of Stress and Appetite Hormones with Binge Eating in Females with Anorexia Nervosa after Weight Restoration: A Longitudinal Study

Binge eating is a transdiagnostic eating disorder symptom that can occur in patients with anorexia nervosa (AN), persisting after weight restoration, and impeding their recovery. However, little is known about the biological predictors of binge eating after AN weight restoration. The goals of this exploratory study of 73 females with AN were: (1) to examine changes in cortisol, the adrenocorticotropic hormone, norepinephrine, ghrelin (total and active), and leptin levels across the admission, discharge, and 3 months post-discharge from the inpatient AN weight restoration; and (2) to determine whether the target hormones were associated with objective or subjective binge eating (OBE or SBE). The participants completed the self-reported Eating Disorder Examination Questionnaire, Beck Anxiety Inventory, and Beck Depression Inventory-II, and provided fasting whole blood samples for hormone assays. The results showed significant changes in body mass index (BMI), cortisol, total ghrelin, and leptin levels over the three time points. The cortisol levels at admission and discharge were significantly associated with the number of SBE episodes at 3 months post-discharge. Findings suggest the need to replicate and confirm the role of cortisol in predicting the emergence of SBE and uncover the mechanisms underlying SBE and cortisol to prevent SBE and its negative consequences.

Loss of control over eating: A systematic review of task based research into impulsive and compulsive processes in binge eating

Recurring episodes of excessive food intake in binge eating disorder can be understood through the lens of behavioral control systems: patients repeat maladaptive behaviors against their explicit intent. Self-report measures show enhanced impulsivity and compulsivity in binge eating (BE) but are agnostic as to the processes that might lead to impulsive and compulsive behavior in the moment. Task-based neurocognitive investigations can tap into those processes. In this systematic review, we synthesize neurocognitive research on behavioral impulsivity and compulsivity in BE in humans and animals, published between 2010-2020. Findings on impulsivity are heterogeneous. Findings on compulsivity are sparse but comparatively consistent, indicating an imbalance of goal-directed and habitual control as well as deficits in reversal learning. We urge researchers to address heterogeneity related to mood states and the temporal dynamics of symptoms, to systematically differentiate contributions of body weight and BE, and to ascertain the validity and reliability of tasks. Moreover, we propose to further scrutinize the compulsivity findings to unravel the computational mechanisms of a potential reinforcement learning deficit.

Effects of stress on chewing and food intake in patients with anorexia nervosa

OBJECTIVE

The present study investigates the impact of psychosocial stress on chewing and eating behavior in patients with anorexia nervosa (P_AN ).

METHOD

The eating and chewing behavior of P_AN were examined in a standardized setting by means of a chewing sensor. These procedures encompassed n = 19 P_AN , age, and gender matched to n = 19 healthy controls (HC). Food intake and chewing frequency were assessed in two experimental conditions: rest versus stress (via Trier Social Stress Test). To verify stress induction, two appraisal scales were employed. In addition, chronic stress, psychological distress and eating disorder symptoms were assessed.

RESULTS

In terms of food intake and chewing frequency, the results of the 2x2 ANOVA demonstrated a significant effect of condition and group. During stress, all participants demonstrated a higher chewing frequency and a decreased ingestion. In general, patients ate less at a lower chewing frequency (vs. HC). However, sample specific analyses demonstrated that the eating and chewing behavior of P_AN remained unchanged regardless of the condition, except for their drinking. Food choices were comparable between the groups, but appetite values significantly differed.

DISCUSSION

The increase in chewing frequency in all participants during stress suggests that chewing might impact affect regulation, however, not specifically in P_AN . Future research should clarify to what extent the normalization of chewing behavior could ameliorate ED-symptoms (incl. food intake) in P_AN . The application of a chewing sensor could support this aim and future interventions.

Emotional reactivity and eating disorder related attitudes in response to the trier social stress test: An experimental study in people with anorexia nervosa and with bulimia nervosa

BACKGROUND

In order to experimentally asses the role of socio-emotional problems in Eating Disorder (ED) psychopathology, we have measured affective states and ED-related attitudes in response to an acute psychosocial stress and their relationships with interpersonal sensitivity in people with Anorexia Nervosa (AN) and Bulimia Nervosa (BN).

METHODS

Twenty-one women with AN, 21 with BN and 27 healthy women underwent an acute psycho-social challenge, the Trier Social Stress Test. Anxiety feelings, hunger perception, amount of desired food and body dissatisfaction were measured throughout the experimental procedure. The relationships between these variables and with interpersonal sensitivity measures were explored through Pearson's correlation and mediation analyses.

RESULTS

Stress-induced anxiety was increased in people with EDs. People with AN showed reduced hunger perception, decreased desire for food and a negative association between anxiety feelings and desire for food. In people with EDs, baseline ineffectiveness predicted post-stress body dissatisfaction through the mediation of post-stress anxiety levels.

LIMITATIONS

The relatively low sample size and the lack of an experimental control condition are the main limitations of the study.

CONCLUSIONS

The present findings show, for the first time, the relationships between socio-emotional distress and ED-related attitudes in people with EDs, providing experimental support to the interpersonal model of EDs. This gives empirical evidence to treatments targeting interpersonal problems in EDs.

Toward a unifying theory of dysregulated behaviors

Dysregulated behaviors, defined as active behaviors that have short-term benefits but cause serious recurrent long-term distress or impairment to the individual and/or those around them, include behaviors such as suicidal and nonsuicidal self-injury, aggression, and substance use. These behaviors are common and costly to the individual, their friends and family, and society. Despite similar etiological models and interventions, dysregulated behaviors have largely been studied in isolation from one another. The goals of this paper were to a) define dysregulated behaviors as a coherent class of behaviors, b) review the prevalence and consequences of dysregulated behaviors, c) outline how dysregulated behaviors fit into current models of psychopathology, and d) describe the key questions to be addressed by future research in this area. It is argued that integrating across theories of discrete dysregulated behaviors can help provide aid in the development of etiological models, which in turn can improve prevention and intervention for dysregulated behaviors.

Weight Stigmatization and Binge Eating in Asian Americans with Overweight and Obesity

Weight stigma and binge eating have been found to be associated in Western populations; however, this relationship is understudied among Asian Americans. The aims of the study were to (1) investigate the prevalence of binge eating and its relationship with experienced weight stigma in higher-weight Asian Americans, and (2) examine whether the level of acculturation moderates this relationship. Data were collected from a cross-sectional study with 166 higher-weight Asian American adults living in North Carolina, United States. Demographic data, the frequency of experiencing weight stigma, the severity of binge eating, the levels of acculturation, the perceived racism against Asians, and perceived stress were assessed via self-reported questionnaires. The results indicated that experienced weight stigma was a significant independent predictor over and above the effects of other stressors, such as racism and general stress. The level of acculturation did not influence the relationship between the experienced weight stigma and binge eating after adjusting for relevant covariates. Our findings contribute to the limited literature examining weight stigma and binge eating among Asian American populations, highlighting that higher levels of experienced weight stigma are associated with a greater degree of binge eating.

Initial development and validation of the Online Appearance-Relevant Peer Conversations Scale

In this research, we present three studies on the development and validation of the Online Appearance-Relevant Peer Conversations Scale (OARPCS), a 12-item measure of (1) physical appearance and (2) life stressors as foci of online peer communications. In Study 1, young Chinese adults (N = 800) completed OARPCS items and measures of body image, Internet use, and general distress. Exploratory factor analyses supported the hypothesized two factor structure and within gender correlation analyses provided construct validity support. Study 2 replicated the EFA-derived OARPCS factor structure and validity further within confirmatory factor analyses of young adults from Chongqing (N = 750) and Macau (N = 994). Study 3 assessed the predictive validity of OARPCS dimensions in relation to prospective changes in cosmetic surgery consideration, eating disturbances and perceived stress over one year (N = 796). Independent of baseline responses on outcomes, baseline physical appearance and life stressor subscale scores, respectively, explained modest, significant variance in women's body image concerns and men's reported stress. Together, results underscored appearance-relevant content in online peer interactions as influences on body image and emotional status and provided psychometric support for a brief self-report measure of these factors.

Neurocognitive findings in young adults with binge eating disorder

Objectives: Binge-eating disorder (BED) has been associated with cognitive impairment, including on measures of impulsivity, but it is not clear in prior literature whether these deficits may have been associated with obesity, rather than BED per se. Impulsivity may play a role in predisposing people towards BED as well as in the chronicity of symptoms. The aim of this study was to examine cognitive functions between BED and healthy controls matched for age, gender, and body mass indices.Methods: Individuals with BED and healthy controls were recruited from the general community using media advertisements. After providing informed consent, study participants completed a clinical interview and computerised neuropsychological testing. Group differences were analysed.Results: Groups did not differ significantly on age, gender, education levels, or body mass indices. The BED group (N = 17) exhibited significantly impaired stop-signal response inhibition (Stop-Signal Task) and executive planning (Stockings of Cambridge Task) compared to healthy controls (N = 17). Spatial working memory and set-shifting were intact.Discussion: BED appears to be associated with motor disinhibition and impaired executive planning even controlling for obesity. Longitudinal work is needed to clarify whether motor impulsivity predisposes people to BED, and/or contributes to persistence of symptoms over time.Key pointsBinge-eating disorder is common, under-recognised, and associated with untoward physical and health sequelae.The neurobiological basis of binge-eating disorder is unclear; cognitive testing may offer insights.Many prior cognitive studies have not controlled for potential confounds, especially group differences in body mass indices (BMI). Obesity in itself has been linked with cognitive dysfunction.Here, we compared cognition between people with binge-eating disorder and controls, matched for BMI and other measures.Binge-eating disorder was associated with impaired response inhibition and executive planning.These results inform neurobiological models of binge-eating disorder and may suggest new treatment targets for this condition.

Eat to avoid negative self-awareness: Locus of control and core self-evaluation as serial mediators in the effect of stress on food intake

The primary hypothesis of escape theory lies in that those who are under stress eat to escape from negative self-awareness. Although escape theory has been well cited in the eating literature, relatively few studies have directly tested its applicability to stress-induced eating. The aim of the present study is to provide causal evidence on using escape theory to explain the effect of stress on food intake. Specifically, we examined whether locus of control (LOC) and core self-evaluation (CSE) are serial mediators in the effect of stress on food intake. By a longitudinal experimental design, participants were randomly assigned to a stress group or a control group, and data on LOC, CSE, and food intake were collected at 3 waves. The results indicated that LOC and CSE are serial mediators in the effect of stress on food intake, though the direct effect of stress conditions remained significant. Our findings support the applicability of escape theory to interpret why stress increases food intake, and exclusion of LOC as an indicator of CSE. Thus, the present study provides causal evidence on escape theory by shedding light on the sequential mediating effect of LOC and CSE. Future research need to pay more attention to the evaluative process in stress-induced eating.

Stress as a potential moderator of ovarian hormone influences on binge eating in women

Previous research has demonstrated significant associations between increased levels of ovarian hormones and increased rates of binge eating (BE) in women. However, whereas all women experience fluctuations in ovarian hormones across the menstrual cycle, not all women binge eat in response to these fluctuations, suggesting that other factors must contribute. Stress is one potential contributing factor. Specifically, it may be that hormone-BE associations are stronger in women who experience high levels of stress, particularly as stress has been shown to be a precipitant to BE episodes in women. To date, no studies have directly examined stress as a moderator of hormone-BE associations, but indirect data (that is, associations between BE and stress and between ovarian hormones and stress) could provide initial clues about moderating effects. Given the above, the purpose of this narrative review was to evaluate these indirect data and their promise for understanding the role of stress in hormone-BE associations. Studies examining associations between all three phenotypes (that is, ovarian hormones, stress, and BE) in animals and humans were reviewed to provide the most thorough and up-to-date review of the literature on the potential moderating effects of stress on ovarian hormone-BE associations. Overall, current evidence suggests that associations between hormones and BE may be stronger in women with high stress levels, possibly via altered hypothalamic-pituitary-adrenal axis response to stress and increased sensitivity to and altered effects of ovarian hormones during stress. Additional studies are necessary to directly examine stress as a moderator of ovarian hormone-BE associations and identify the mechanisms underlying these effects.

Bite count rates in free-living individuals: new insights from a portable sensor

Background

Conclusions regarding bite count rates and body mass index (BMI) in free-living populations have primarily relied on self-report. The objective of this exploratory study was to compare the relationship between BMI and bite counts measured by a portable sensor called the Bite Counter in free-living populations and participants eating in residence.

Methods

Two previously conducted studies were analyzed for relationships between BMI and sensor evaluated bite count/min, and meal duration. Participants from the first study (N = 77) wore the bite counter in a free-living environment for a continuous period of 14 days. The second study (N = 214) collected bite count/min, meal duration, and total energy intake in participants who consumed one meal in a cafeteria. Linear regression was applied to examine relationships between BMI and bite count/min.

Results

There was no significant correlation in the free-living participants average bite counts per second and BMI (R² = 0.03, p = 0.14) and a significant negative correlation in the cafeteria participants (R² = 0.04, p = 0.03) with higher bite count rates observed in lean versus obese participants. There was a significant correlation between average meal duration and BMI in the free-living participants (R² = 0.08, p = 0.01). Total energy intake in the cafeteria participants was also significantly correlated to meal duration (R² = 0.31, p < 0.001).

Conclusions

With additional novel applications of the Bite Counter, insights into free-living eating behavior may provide avenues for future interventions that are sustainable for long term application.

Screening for Binge Eating Disorder in people with obesity

The Risk factors for Binge Eating Disorder in Overweight (REO) questionnaire is a screening tool for nutritionists to discriminate between individuals with obesity with and without Binge Eating Disorder (BED). The first study tested the discriminative ability of the REO and identified an optimal cut-off value. In the second study this cut-off value was used to identify individuals with and without BED from a sample of individuals with obesity visiting a nutritionist and compared clinical and personality characteristics with a group of individuals officially diagnosed with BED. Results showed that the REO has a sensitivity of 95.1%, specificity of 81.5%, a good internal consistency of α=.96, and an exploratory factor analysis showed four underlying factors of the REO that explained a total variance of 63.7%. Characteristics of individuals with BED symptoms identified by the REO and those officially diagnosed with BED were comparable and differed from individuals with obesity without BED symptoms. By screening individuals with obesity with the REO those presenting with BED symptoms are more easily identified, and can be referred to psychological treatment facilities for further assessment and appropriate treatment.

Characterizing emotional overeating among patients with and without binge-eating disorder in primary care

OBJECTIVE

Emotional overeating and loss-of-control eating are associated with poorer weight-related and psychiatric outcomes, yet our understanding of the relationship between these variables is limited, particularly among individuals in primary care. This study examined the frequency of emotional overeating and relationship with loss-of-control eating among patients with and without binge-eating disorder (BED) seeking weight loss treatment in primary care.

METHOD

Participants were 131 adults (n = 105 female) with overweight/obesity seeking weight loss treatment in primary care. Participants completed the Eating Disorder Examination (semi-structured interview) and Yale Emotional Overeating Scale, which measures emotional overeating episodes. Height and weight were measured. Mean age and BMI were 47.60 years and 35.31 kg/m², respectively. BED criteria were met by n = 35 (26.7%) participants.

RESULTS

Participants with BED endorsed more frequent emotional overeating episodes compared to those without BED. While total emotional overeating scores were not associated with loss-of-control eating, discrete types of emotional overeating episodes (e.g., loneliness) were associated with loss-of-control eating. Emotional overeating was most often reported in response to loneliness, boredom, or anxiety, which varied by BED status.

CONCLUSIONS

Most participants endorsed recent episodes of emotional overeating; those with BED endorsed more frequent episodes. Future research examining the impact of emotional overeating on weight loss treatment outcomes is warranted.

Emotion Regulation in Binge Eating Disorder: A Review

The purpose of the present review is to provide a summary of the research findings on emotion regulation in Binge Eating Disorder (BED). Negative emotions and maladaptive emotion regulation strategies play a role in the onset and maintenance of binge eating in BED. Anger and sadness, along with negative emotions related to interpersonal experiences (i.e., disappointment, being hurt or loneliness), seem to be particularly relevant. Individuals with BED have a tendency to suppress and ruminate on their unwanted emotions, which leads to increased psychopathological thoughts and symptoms. Compared to healthy controls, they use adaptive strategies, such as reappraisal, less frequently. Evidence concerning the causal relation between negative affect and binge eating is inconclusive and still very limited. While experimental studies in a laboratory setting lack ecological validity, ecological momentary assessment studies offer more promise at unraveling the causal relationship between emotions and binge eating. Increases in negative affect are found to be antecedents of binge eating in BED. However, there seems to be less support for the possibility that binge eating serves as a means to alleviate negative affect. Finally, BED seems to be related to other forms of maladaptive emotion regulation strategies, such as substance abuse and self-harm.

Stress, overeating, and obesity: Insights from human studies and preclinical models

Eating disorders and obesity have become predominant in human society. Their association to modern lifestyle, encompassing calorie-rich diets, psychological stress, and comorbidity with major diseases are well documented. Unfortunately the biological basis remains elusive and the pharmacological treatment inadequate, in part due to the limited availability of valid animal models. Human research on binge eating disorder (BED) proves a strong link between stress exposure and bingeing: state-levels of stress and negative affect are linked to binge eating in individuals with BED both in laboratory settings and the natural environment. Similarly, classical animal models of BED reveal an association between acute exposure to stressors and binging but they are often associated with unchanged or decreased body weight, thus reflecting a negative energy balance, which is uncommon in humans where most commonly BED is associated with excessive or unstable body weight gain. Recent mouse models of subordination stress induce spontaneous binging and hyperphagia, altogether more closely mimicking the behavioral and metabolic features of human BED. Therefore the translational relevance of subordination stress models could facilitate the identification of the neurobiological basis of BED and obesity-associated disease and inform on the development of innovative therapies.

Ecological Momentary Assessment in Behavioral Research: Addressing Technological and Human Participant Challenges

Background

Ecological momentary assessment (EMA) assesses individuals’ current experiences, behaviors, and moods as they occur in real time and in their natural environment. EMA studies, particularly those of longer duration, are complex and require an infrastructure to support the data flow and monitoring of EMA completion.

Objective

Our objective is to provide a practical guide to developing and implementing an EMA study, with a focus on the methods and logistics of conducting such a study.

Methods

The EMPOWER study was a 12-month study that used EMA to examine the triggers of lapses and relapse following intentional weight loss. We report on several studies that informed the implementation of the EMPOWER study: (1) a series of pilot studies, (2) the EMPOWER study’s infrastructure, (3) training of study participants in use of smartphones and the EMA protocol and, (4) strategies used to enhance adherence to completing EMA surveys.

Results

The study enrolled 151 adults and had 87.4% (132/151) retention rate at 12 months. Our learning experiences in the development of the infrastructure to support EMA assessments for the 12-month study spanned several topic areas. Included were the optimal frequency of EMA prompts to maximize data collection without overburdening participants; the timing and scheduling of EMA prompts; technological lessons to support a longitudinal study, such as proper communication between the Android smartphone, the Web server, and the database server; and use of a phone that provided access to the system’s functionality for EMA data collection to avoid loss of data and minimize the impact of loss of network connectivity. These were especially important in a 1-year study with participants who might travel. It also protected the data collection from any server-side failure. Regular monitoring of participants’ response to EMA prompts was critical, so we built in incentives to enhance completion of EMA surveys. During the first 6 months of the 12-month study interval, adherence to completing EMA surveys was high, with 88.3% (66,978/75,888) completion of random assessments and around 90% (23,411/25,929 and 23,343/26,010) completion of time-contingent assessments, despite the duration of EMA data collection and challenges with implementation.

Conclusions

This work informed us of the necessary preliminary steps to plan and prepare a longitudinal study using smartphone technology and the critical elements to ensure participant engagement in the potentially burdensome protocol, which spanned 12 months. While this was a technology-supported and -programmed study, it required close oversight to ensure all elements were functioning correctly, particularly once human participants became involved.

The Role of Essential Fatty Acids in Anorexia Nervosa and Obesity

The two basic questions in food intake study are what we eat, and how much do we eat. Most research is directed toward the control of how much is eaten. This is likely the result of the increased number of individuals with eating disorders in the Western world. Feeding behavior is highly complex, and is controlled by many psychological, physiological, biochemical, and immunological factors. The aim of this review is to clarify the involvement of fatty acids in eating disorders such as anorexia and binge eating disorder. The review will describe the modified fatty acid profile observed in individuals with anorexia or binge eating disorder, and discuss on what factors fatty acids can exert beneficial effects. In addition, the differences and similarities between anorexia and binge eating disorder will be discussed. We suggest that beneficial effects of essential fatty acids on both anorexia and binge eating disorder can be explained by the stabilizing effect of those fatty acids on the neuronal membrane fluidity index.

A new universal dynamic model to describe eating rate and cumulative intake curves

BACKGROUND

Attempts to model cumulative intake curves with quadratic functions have not simultaneously taken gustatory stimulation, satiation, and maximal food intake into account.

OBJECTIVE

Our aim was to develop a dynamic model for cumulative intake curves that captures gustatory stimulation, satiation, and maximal food intake.

DESIGN

We developed a first-principles model describing cumulative intake that universally describes gustatory stimulation, satiation, and maximal food intake using 3 key parameters: 1) the initial eating rate, 2) the effective duration of eating, and 3) the maximal food intake. These model parameters were estimated in a study (n = 49) where eating rates were deliberately changed. Baseline data was used to determine the quality of model's fit to data compared with the quadratic model. The 3 parameters were also calculated in a second study consisting of restrained and unrestrained eaters. Finally, we calculated when the gustatory stimulation phase is short or absent.

RESULTS

The mean sum squared error for the first-principles model was 337.1 ± 240.4 compared with 581.6 ± 563.5 for the quadratic model, or a 43% improvement in fit. Individual comparison demonstrated lower errors for 94% of the subjects. Both sex (P = 0.002) and eating duration (P = 0.002) were associated with the initial eating rate (adjusted R² = 0.23). Sex was also associated (P = 0.03 and P = 0.012) with the effective eating duration and maximum food intake (adjusted R² = 0.06 and 0.11). In participants directed to eat as much as they could compared with as much as they felt comfortable with, the maximal intake parameter was approximately double the amount. The model found that certain parameter regions resulted in both stimulation and satiation phases, whereas others only produced a satiation phase.

CONCLUSIONS

The first-principles model better quantifies interindividual differences in food intake, shows how aspects of food intake differ across subpopulations, and can be applied to determine how eating behavior factors influence total food intake.

Stress-induced eating in women with binge-eating disorder and obesity

The purpose of the current study was to investigate stress-induced eating in women with binge-eating disorder (BED) and obesity. Three groups of women [obese with BED (n=9); obese non-BED (n=11); and normal weight (NW) non-BED (n=12)], rated their levels of hunger and psychological distress before and after completing the Trier Social Stress Test, followed by food anticipation and then consumption of their preferred snack food. We differentiated between the motivational and hedonic components of eating by measuring the amount of food participants poured into a serving bowl compared to the amount consumed. Stress did not affect poured and consumed calories differently between groups. Across all subjects, calories poured and consumed were positively correlated with post-stress hunger, but calories poured was positively correlated with post-stress anxiety and negative affect. These results indicate that stress-related psychological factors may be more strongly associated with the motivational drive to eat (i.e. amount poured) rather than the hedonic aspects of eating (i.e. amount consumed) for women in general. Exploratory correlation analyses per subgroup suggest that post-stress hunger was positively associated with calories poured and consumed in both non-BED groups. In the obese BED group, calories consumed was negatively associated with dietary restraint and, although not significantly, positively associated with stress-induced changes in anxiety.These findings suggest that stress-induced snacking in obese BED women may be influenced by psychological factors more so than homeostatic hunger mechanisms. After controlling for dietary restraint and negative affect, the NW non-BED women ate a greater percentage of the food they poured than both obese groups, suggesting that obesity may be associated with a heightened motivational drive to eat coupled with a reduction in hedonic pleasure from eating post-stress. Further studies that incorporate novel approaches to measuring the motivational versus hedonic aspects of stress-induced eating may expose nuanced eating behaviors that differentiate BED and obesity. If confirmed, our findings would support prevention and treatment strategies that target subsets of women based on obesity and BED status.

Acute Stressors Reduce Neural Inhibition to Food Cues and Increase Eating Among Binge Eating Disorder Symptomatic Women

Stressors can trigger binge-eating but researchers have yet to consider their effects on both neural responses to food cues and food consumption among those at risk. In this experiment, we examined the impact of acute stressors on neural activation to food images and subsequent food consumption within binge-eating disorder (BED) and non-eating disordered control groups. Eighteen women meeting DSM-IV BED criteria and 26 women serving as non-eating disordered controls were randomly assigned to unpleasant stressor (painful cold pressor test (CPT) followed by negative performance feedback) or less unpleasant stressor (non-painful sensory discrimination task followed by positive performance feedback) conditions. Subsequently, they were scanned with functional magnetic resonance imaging (fMRI) while viewing food and neutral images. After the scans, participants completed a self-report battery in an environment conducive to snacking. During exposure to food images, BED-symptomatic women in the unpleasant stressor condition reported more liking of high calorie food images and showed less activation in one inhibitory area, the hippocampus, compared to controls in this condition. BED-symptomatic women exposed to unpleasant stressors also consumed more chocolate than any other group during the post-scan questionnaire completion. Crucially, reduced hippocampal activation to high calorie food images predicted more chocolate consumption following fMRI scans within the entire sample. This experiment provides initial evidence suggesting unpleasant acute stressors contribute to reduced inhibitory region responsiveness in relation to external food cues and later food consumption among BED-symptomatic women.

Crave, Like, Eat: Determinants of Food Intake in a Sample of Children and Adolescents with a Wide Range in Body Mass

Obesity is a heterogeneous condition with obese individuals displaying different eating patterns. Growing evidence suggests that there is a subgroup of obese adults that is marked by frequent and intense food cravings and addiction-like consumption of high-calorie foods. Little is known, however, about such a subgroup of obese individuals in childhood and adolescence. In the present study, a sample of children and adolescents with a wide range in body mass was investigated and trait food craving, liking for and intake of high- and low-calorie foods was measured. One-hundred and forty-two children and adolescents (51.4% female, n = 73; Mage = 13.7 years, SD = 2.25; MBMI-SDS = 1.26, SD = 1.50) completed the Food Cravings Questionnaire-Trait, then viewed pictures of high- and low-calorie foods and rated their liking for them, and subsequently consumed some of these foods in a bogus taste test. Contrary to expectations, higher body mass was associated with lower consumption of high-calorie foods. However, there was an interaction between body mass and trait food craving when predicting food consumption: in obese participants, higher trait food craving was associated with higher consumption of high-calorie foods and this association was not found in normal-weight participants. The relationship between trait food craving and high-calorie food consumption within obese individuals was mediated by higher liking for high-calorie foods (but not by liking for low-calorie foods). Thus, similar to adults, a subgroup of obese children and adolescents - characterized by high trait food craving - seems to exist, calling for specific targeted treatment strategies.

Stress in owned cats: behavioural changes and welfare implications

Domestic cats are exposed to a variety of stressful stimuli, which may have a negative effect on the cats' welfare and trigger a number of behavioural changes. Some of the stressors most commonly encountered by cats include changes in environment, inter-cat conflict, a poor human-cat relationship and the cat's inability to perform highly motivated behaviour patterns. Stress is very likely to reduce feed intake, and stress-related anorexia may contribute to the development of potentially serious medical conditions. Stress also increases the risk of cats showing urine marking and some forms of aggression, including redirected aggression. A number of compulsive disorders such as over-grooming may also develop as a consequence of stressful environments. Some of the main strategies to prevent or reduce stress-related behavioural problems in cats are environmental enrichment, appropriate management techniques to introduce unfamiliar cats to each other and the use of the synthetic analogue of the feline facial pheromone. As the stress response in cats depends, to a large extent, on the temperament of the animal, breeding and husbandry strategies that contribute to the cat developing a well-balanced temperament are also very useful.

Recognizing Binge-Eating Disorder in the Clinical Setting: A Review of the Literature

OBJECTIVE

Review the clinical skills needed to recognize, diagnose, and manage binge-eating disorder (BED) in a primary care setting.

DATA SOURCES

A PubMed search of English-language publications (January 1, 2008-December 11, 2014) was conducted using the term binge-eating disorder. Relevant articles known to the authors were also included.

STUDY SELECTION/DATA EXTRACTION

Publications focusing on preclinical topics (eg, characterization of receptors and neurotransmitter systems) without discussing clinical relevance were excluded. A total of 101 publications were included in this review.

RESULTS

Although BED is the most prevalent eating disorder, it is underdiagnosed and undertreated. BED can be associated with medical (eg, type 2 diabetes and metabolic syndrome) and psychiatric (eg, depression and anxiety) comorbidities that, if left untreated, can impair quality of life and functionality. Primary care physicians may find diagnosing and treating BED challenging because of insufficient knowledge of its new diagnostic criteria and available treatment options. Furthermore, individuals with BED may be reluctant to seek treatment because of shame, embarrassment, and a lack of awareness of the disorder. Several short assessment tools are available to screen for BED in primary care settings. Pharmacotherapy and psychotherapy should focus on reducing binge-eating behavior, thereby reducing medical and psychiatric complications.

CONCLUSIONS

Overcoming primary care physician- and patient-related barriers is critical to accurately diagnose and appropriately treat BED. Primary care physicians should take an active role in the initial recognition and assessment of suspected BED based on case-finding indicators (eg, eating habits and being overweight), the initial treatment selection, and the long-term follow-up of patients who meet DSM-5 BED diagnostic criteria.

The "Smart Dining Table": Automatic Behavioral Tracking of a Meal with a Multi-Touch-Computer

Studying how humans eat in the context of a meal is important to understanding basic mechanisms of food intake regulation and can help develop new interventions for the promotion of healthy eating and prevention of obesity and eating disorders. While there are a number of methodologies available for behavioral evaluation of a meal, there is a need for new tools that can simplify data collection through automatic and online analysis. Also, there are currently no methods that leverage technology to add a dimension of interactivity to the meal table. In this study, we examined the feasibility of a new technology for automatic detection and classification of bites during a laboratory meal. We used a SUR40 multi-touch tabletop computer, powered by an infrared camera behind the screen. Tags were attached to three plates, allowing their positions to be tracked, and the saturation (a measure of the infrared intensity) in the surrounding region was measured. A Kinect camera was used to record the meals for manual verification and provide gesture detection for when the bites were taken. Bite detections triggered classification of the source plate by the SUR40 based on saturation flux in the preceding time window. Five healthy subjects (aged 20–40 years, one female) were tested, providing a total sample of 320 bites. Sensitivity, defined as the number of correctly detected bites out of the number of actual bites, was 67.5%. Classification accuracy, defined as the number of correctly classified bites out of those detected, was 82.4%. Due to the poor sensitivity, a second experiment was designed using a single plate and a Myo armband containing a nine-axis accelerometer as an alternative method for bite detection. The same subjects were tested (sample: 195 bites). Using a simple threshold on the pitch reading of the magnetometer, the Myo data achieved 86.1% sensitivity vs. 60.5% with the Kinect. Further, the precision of positive predictive value was 72.1% for the Myo vs. 42.8% for the Kinect. We conclude that the SUR40 + Myo combination is feasible for automatic detection and classification of bites with adequate accuracy for a range of applications.

The neurobiological basis of binge-eating disorder

Relatively little is known about the neuropathophysiology of binge-eating disorder (BED). Here, the evidence from neuroimaging, neurocognitive, genetics, and animal studies are reviewed to synthesize our current understanding of the pathophysiology of BED. Binge-eating disorder may be conceptualized as an impulsive/compulsive disorder, with altered reward sensitivity and food-related attentional biases. Neuroimaging studies suggest there are corticostriatal circuitry alterations in BED similar to those observed in substance abuse, including altered function of prefrontal, insular, and orbitofrontal cortices and the striatum. Human genetics and animal studies suggest that there are changes in neurotransmitter networks, including dopaminergic and opioidergic systems, associated with binge-eating behaviors. Overall, the current evidence suggests that BED may be related to maladaptation of the corticostriatal circuitry regulating motivation and impulse control similar to that found in other impulsive/compulsive disorders. Further studies are needed to understand the genetics of BED and how neurotransmitter activity and neurocircuitry function are altered in BED and how pharmacotherapies may influence these systems to reduce BED symptoms.

The association between emotions and eating behaviour in an obese population with binge eating disorder

There is utility in understanding the antecedents of binge eating (BE), with a view to explaining poorer weight loss treatment responses in this subgroup. A systematic review was completed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines with the aim of exploring associations between emotions and eating behaviour in a population affected by obesity and binge eating disorder (BED). A comprehensive literature search of four electronic databases (2004-2014) yielded 15 studies for inclusion. Included studies performed poorly on data quality analysis with respect to controlling for confounding variables, and sample size. Included papers largely focused on negative emotions as antecedents of BE; depression was consistently associated with a BED-obese classification and BE. Negative mood, sadness, tension and instability of emotions were found to be antecedents of BE in an adult BED-obese sample. However, findings were mixed regarding the role of stress, anger and positive emotions within the BED-obese population. Recommendations are presented for the identification of BED, and ecologically valid experimental designs that further understanding of the complex and varied emotions that associate with BE. The implications of these and other limitations for both researchers and practitioners are discussed. The paper concludes with recommendations for future research alongside suggestions for practitioners. © 2015 World Obesity.

Insights revealed by rodent models of sugar binge eating

Binge eating is seen across the spectrum of eating disorder diagnoses as well as among individuals who do not meet diagnostic criteria. Analyses of the specific types of foods that are frequently binged upon reveal that sugar-rich items feature prominently in binge-type meals, making the effects of binge consumption of sugar an important focus of study. One avenue to do this involves the use of animal models. Foundational and recent studies of animal models of sugar bingeing, both outlined here, lend insight into the various neurotransmitters and neuropeptides that may participate in or be altered by this behavior. Further, several preclinical studies incorporating sugar bingeing paradigms have explored the utility of pharmacological agents that target such neural systems for reducing sugar bingeing in an effort to enhance clinical treatment. Indeed, the translational implications of findings generated using animal models of sugar bingeing are considered here, along with potential avenues for further study.

Diagnosing binge eating disorder in a primary care setting

Binge eating disorder (BED), now recognized as a distinct eating disorder in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, is the most prevalent eating disorder. Although nearly half of individuals with BED are obese, BED also occurs in nonobese individuals. Despite the relatively high percentage of weight loss treatment-seeking individuals meeting BED criteria, primary care physicians may not be familiar with or have ever diagnosed BED. Many providers may also have difficulty distinguishing BED as a contributory factor in obesity. This review differentiates BED from other causes of obesity by describing how obese individuals with BED differ from obese individuals without BED and from nonobese individuals with BED in areas including psychopathology, behavior, genetics, physiology, quality of life and productivity. The ways in which health-care providers can identify individuals who may have BED are also highlighted so the proper course of treatment is pursued. Overall, obese individuals with BED demonstrate a number of key characteristics that differentiate them from obese individuals without eating disorders, including increased impulsivity in response to food stimuli with loss of control over eating, resulting in the consumption of more calories. They also experience significant guilt and other negative emotions following a meal. In addition, individuals with BED patients have more psychiatric comorbidity, display more psychopathology, exhibit longer binge durations, consume more meals as snacks during the day and have less dietary restraint compared with individuals with BED who are not obese. However, the differences between individuals with BED who are obese versus not obese are not as prominent. Taken together, the evidence appears to support the conclusion that BED is a unique and treatable neurobehavioral disorder associated with distinct behavioral and psychological profiles and distinct medical and functional outcomes, and that it is not merely a subtype of obesity.

Neuropeptide W-Induced Hypophagia is Mediated Through Corticotropin-Releasing Hormone-Containing Neurons

Neuropeptide W (NPW), which was originally isolated from the porcine hypothalamus, has been identified as the endogenous ligand for both the NPBWR1 (GPR7) and NPBWR2 (GPR8) receptors. These receptors, which belong to the orphan G protein-coupled receptor (GPCR) family, share a high sequence homology with the opioid and somatostatin receptor families. NPW and NPBWR1 are widely distributed in the rat central nervous system (CNS). While the intracerebroventricular (i.c.v.) injection of NPW elevates plasma corticosterone levels, the intravenous administration of NPW in conjunction with a corticotropin-releasing hormone (CRH) antagonist blocks NPW-induced corticosterone secretion. It has been reported that NPW is involved in regulating the hypothalamus-pituitary-adrenal cortex (HPA) axis and that i.c.v. administration of NPW decreases feeding behavior. The aim of the present study was to ascertain if NPW's role in feeding regulation is mediated (or not) through corticotropin-releasing hormone (CRH)-containing neurons. We found that NPW-containing axon terminals make synapses with CRH-immunoreactive cell bodies and dendritic processes in the hypothalamic paraventricular nucleus (PVN). The central infusion of NPW significantly induced c-Fos expression in CRH-immunoreactive neurons in the mouse PVN, but not in vasopressin- or oxytocin-immunoreactive neurons. To determine if NPW regulates feeding behavior through CRH neurons, the feeding behavior of mice was studied following the i.c.v. administration NPW in the presence or absence of pretreatment with a CRH antagonist. While NPW administration decreased feeding activity, the CRH antagonist inhibited this effect. These results strongly suggest that NPW regulates feeding behavior through CRH neurons in the mouse brain.

Emotion regulation model in binge eating disorder and obesity--a systematic review

Deficits in emotion regulation processes are a common and widely used explanation for the development and maintenance of binge eating disorder (BED). It is assumed that BED patients - as they have difficulty regulating their negative emotions - use binge eating to cope with these emotions and to find relief. However, the number of experimental studies investigating this assumption is scarce and the differentiation of obese individuals with and without BED regarding the emotion regulation model is not verified. We reviewed literature for experimental studies investigating the emotion regulation model in obese patients (OB) with and without BED. Our search resulted in 18 experimental studies examining the triggering effect of negative emotions for binge eating or its effects on subsequent relief. We found evidence indicating that negative emotion serves as a trigger for binge eating in the BED group unlike the obese group without BED. Considering the small number of studies, we found evidence for a (short-term) improvement of mood through food intake, irrespective of group.

Chewing after stress: psychosocial stress influences chewing frequency, chewing efficacy, and appetite

BACKGROUND

Psychosocial stress is accompanied by an increase in the activity of the hypothalamic-pituitary-adrenocortical (HPA)-axis and by an increase in food intake. At present, no studies have been conducted to examine the impact of a potent laboratory stress test on the chewing frequency.

METHODS

Thirty-one healthy participants (14 females, mean age 27.13) were compared after they had fulfilled the protocol of a standardized psychosocial stress test, the Trier Social Stress Test (TSST), and after a resting condition of silent reading in reference to their chewing frequency, chewing efficacy, food intake, and eating preferences. As part of the design free salivary cortisol levels and heart rate variability were measured repeatedly before and after the TSST and the resting condition.

RESULTS

After the TSST, the participants exhibited a significantly higher mean chewing frequency than after the resting condition (F(2,60)=3.600, p=.035, η(2)=.107). The testing condition had no influence on the amount of food intake. Following the psychosocial stress, however, the participants reported a significantly less general appetite (Z=-3.921, p<.001) and less of an appetite for eggs (Z=-2.023, p=.043) than after their resting condition. No correlation was found between the salivary cortisol response and the chewing frequency.

CONCLUSION

The results indicated that psychosocial stress is associated with an increase in chewing frequency, as measured with a sound-based apparatus, and with a decrease in appetite.

Overlap of food addiction and substance use disorders definitions: analysis of animal and human studies

Food has both homeostatic and hedonic components, which makes it a potent natural reward. Food related reward could therefore promote an escalation of intake and trigger symptoms associated to withdrawal, suggesting a behavioral parallel with substance abuse. Animal and human theoretical models of food reward and addiction have emerged, raising further interrogations on the validity of a bond between Substance Use Disorders, as clinically categorized in the DSM 5, and food reward. These models propose that highly palatable food items, rich in sugar and/or fat, are overly stimulating to the brain's reward pathways. Moreover, studies have also investigated the possibility of causal link between food reward and the contemporary obesity epidemic, with obesity being potentiated and maintained due to this overwhelming food reward. Although natural rewards are a hot topic in the definition and categorization of Substance Use Disorders, proofs of concept and definite evidence are still inconclusive. This review focuses on available results from experimental studies in animal and human models exploring the concept of food addiction, in an effort to determine if it depicts a specific phenotype and if there is truly a neurobiological similarity between food addiction and Substance Use Disorders. It describes results from sugar, fat and sweet-fat bingeing in rodent models, and behavioral and neurobiological assessments in different human populations. Although pieces of behavioral and neurobiological evidence supporting a food addiction phenotype in animals and humans are interesting, it seems premature to conclude on its validity.

Biological and psychological markers of stress in humans: focus on the Trier Social Stress Test

Validated biological and psychological markers of acute stress in humans are an important tool in translational research. The Trier Social Stress Test (TSST), involving public interview and mental arithmetic performance, is among the most popular methods of inducing acute stress in experimental settings, and reliably increases hypothalamic-pituitary-adrenal axis activation. However, although much research has focused on HPA axis activity, the TSST also affects the sympathetic-adrenal-medullary system, the immune system, cardiovascular outputs, gastric function and cognition. We critically assess the utility of different biological and psychological markers, with guidance for future research, and discuss factors which can moderate TSST effects. We outline the effects of the TSST in stress-related disorders, and if these responses can be abrogated by pharmacological and psychological treatments. Modified TSST protocols are discussed, and the TSST is compared to alternative methods of inducing acute stress. Our analysis suggests that multiple readouts are necessary to derive maximum information; this strategy will enhance our understanding of the psychobiology of stress and provide the means to assess novel therapeutic agents.