Negative affect, dietary restriction, and food choice in bulimia nervosa

Testing "Feeling Fat" as a Mediator of the Longitudinal Relationship Between Negative Emotions and Eating Disorder Behaviors

OBJECTIVE

Negative affect is central to eating disorder maintenance models; identifying mechanisms underlying this link may inform specific treatment targets. The current study evaluated which emotions (i.e., distress, fear, and moral emotions) were most strongly linked to feeling fat and tested feeling fat as a longitudinal mediator of the relationship between these emotions and restricting or binge eating (https://osf.io/3d5cq/).

METHOD

Community adults (N = 714, M[SD] age = 41.5[13.7], 84.6% female, 85.9% white) provided data at baseline, 3-month, and 6-month follow-up. Relative weights analysis examined which emotion categories exhibited the strongest longitudinal relationships with feeling fat. Cross-lagged panel models tested feeling fat as a mediator of the relationship between emotions and eating disorder behaviors.

RESULTS

Distress and moral emotions were the strongest emotional predictors of feeling fat. Feeling fat predicted binge eating (p's < 0.001), but not restricting (p's ≥ 0.832), in random effects cross-lagged panel models. Feeling fat partially mediated the longitudinal relationship between distress and binge eating (p = 0.044); however, this effect became nonsignificant after adjusting for BMI (p = 0.354). Feeling fat did not mediate relationships between moral emotions and binge eating or between either distress or moral emotions and restricting (p's ≥ 0.638).

DISCUSSION

Feeling fat was associated with binge eating, not restricting, highlighting the importance of specificity in maintenance models. Because the mediating effect of feeling fat was accounted for by body size, factors associated with body size, such as internalized weight stigma, may be more relevant mediators of the relationship between negative emotions and eating disorder behaviors. Future research on feeling fat should adjust for body size.

Starving off death: Mortality salience impacts women's body image and disordered eating

From a Terror Management perspective, the pursuit of thinness that characterizes eating disorders (EDs) is arguably a culturally endorsed way to mitigate death anxiety. In the present studies, we used the mortality salience (MS) paradigm to examine whether priming death increases ED symptoms. We recruited two samples of women from undergraduate (Study 1, N = 120), and clinically relevant (Study 2, N = 154) populations. After priming, participants completed measures of potential confounds (e.g., neuroticism, affect). Next, we assessed ED attitudes and behavior using a portion size estimation task, and measures of body dissatisfaction and eating intention. Study 1 findings were inconsistent with the claimed role of death anxiety in ED related behavior. However, in Study 2, MS priming led to increased dissatisfaction with current thinness and smaller portion sizes for high-fat compared to low-fat food. Overall, the results suggest that death anxiety may, at least partially, drive ED symptoms.

Fronto-temporal dysfunction in appetitive regulation of bulimia nervosa with affective disorders: A regional homogeneity and remote connectivity pattern analysis

OBJECTIVE

The aim of this study was to assess brain functional alterations in BN patients with affective disorders and their association with maladaptive eating behaviors.

METHODS

A total of 42 BN patients with affective disorders (anxiety and depression) and 47 healthy controls (HCs) were enrolled in this study. The resting-state fMRI data were analyzed for functional changes as indicated by regional homogeneity based on Kendall's coefficient of concordance (KCC-ReHo) and seed-based functional connectivity (FC). A principal component analysis (PCA) model was used to identify the commonalities within the behavioral questionnaires from the BN group.

RESULTS

Patients in the BN group showed decreased ReHo in the bilateral middle frontal gyrus (MFG) and right supramarginal gyrus (SMG). Additionally, the BN group showed increased FC between the left MFG and the right inferior temporal gyrus (ITG); decreased FC between the right MFG and the bilateral insula and the left middle temporal gyrus (MTG); and decreased FC between the right SMG and the left superior temporal gyrus (STG) and right inferior frontal gyrus (IFG). In the FC-behavior association analysis, the second principal component (PC2) was negatively correlated with FC between the left MFG and the right ITG.

CONCLUSION

Based on a brain functional analysis (ReHo and FC), this study revealed significant aberrant changes in the frontal-temporal regions of BN patients with affective disorders. These regions, which serve as fronto-temporal circuitry, are associated with restraint and emotional eating behaviors. Our findings shed new light on the neural mechanisms underlying the condition.

Emotional food-cue-reactivity in anorexia nervosa and bulimia nervosa: An electroencephalography study

OBJECTIVE

Food-cue-reactivity entails neural and experiential responses to the sight and smell of attractive foods. Negative emotions can modulate such cue-reactivity and this might be central to the balance between restrictive versus bulimic symptomatology in Anorexia Nervosa (AN) and Bulimia Nervosa (BN).

METHOD

Pleasantness ratings and electrocortical responses to food images were measured in patients with AN (n = 35), BN (n = 32) and matched healthy controls (HC, n = 35) in a neutral state and after idiosyncratic negative emotion induction while electroencephalography (EEG) was recorded. The EEG data were analyzed using a mass testing approach.

RESULTS

Individuals with AN showed reduced pleasantness for foods compared to objects alongside elevated widespread occipito-central food-object discrimination between 170 and 535 ms, indicative of strong neural cue-reactivity. Food-object discrimination was further increased in the negative emotional condition between 690 and 1200 ms over centroparietal regions. Neither of these effects was seen in individuals with BN.

DISCUSSION

Emotion modulated food-cue-reactivity in AN might reflect a decreased appetitive response in negative mood. Such specific (emotion-)regulatory strategies require more theoretical work and clinical attention. The absence of any marked effects in BN suggests that emotional cue-reactivity might be less prominent in this group or quite specific to certain emotional contexts or food types.

PUBLIC SIGNIFICANCE

Negative affectivity is a risk factor for the development of eating disorders and individuals with eating disorders experience problems with emotion regulation. To better understand the effects of negative emotions, the present study investigated how they affected neural correlates of food perception in anorexia nervosa and bulimia nervosa.

Bad mood food? Increased versus decreased food cue reactivity in anorexia nervosa and bulimia nervosa during negative emotions

OBJECTIVE

Emotion regulation difficulties in anorexia nervosa (AN) and bulimia nervosa (BN) might underlie bingeing and purging in BN, extreme fasting in AN, or combinations of these symptoms in binge-purge type AN. In this study, we tested for decreased food cue reactivity in response to negative emotions in AN, and the opposite pattern for BN. Furthermore, we explored subgroup differences (restrictive vs. binge-purging AN; history of AN in BN).

METHOD

Patients with AN (n = 41), BN (n = 39), and matched controls (n = 70) completed an emotional eating questionnaire. In a laboratory experiment, we induced negative emotions and measured food cue reactivity (pleasantness, desire to eat (DTE), and corrugator muscle activity).

RESULTS

AN reported emotional undereating, while BN reported emotional overeating. In the laboratory task, BN showed increased DTE and an appetitive corrugator response during negative emotions, selectively towards high-calorie foods. AN showed generalized reduced cue reactivity to high-calorie food regardless of emotional state. This pattern appears to be characteristic of restrictive AN, while cue reactivity of both BN subgroups pointed towards emotional overeating.

CONCLUSIONS

The emotional over- versus undereating framework might help to explain bingeing and restricting along the anorectic-bulimic disorder spectrum, which calls for novel transdiagnostic theories and subgroup-specific treatments.

Neurobiological and Psychological Maintenance Mechanisms Associated with Anticipatory Reward in Bulimia Nervosa

The purpose of this investigation is to identify the anticipatory reward mechanisms that maintain binge eating and purging in bulimia nervosa. Emerging data indicate the importance of reward and anticipatory processes as maintenance mechanisms of bulimia nervosa that can be targeted in treatment. The proposed research will identify neurobiological and psychological anticipatory mechanisms of binge eating and purging using functional magnetic resonance imaging (fMRI), and ecological momentary assessment (EMA) in the natural environment. In this investigation, 60 adults (30 with bulimia nervosa and 30 matched comparison participants) will undergo negative and positive mood inductions followed by an fMRI food selection task (and a comparison shopping task) to examine neurobiological and affective responses to food and non-food reward anticipation. Participants with bulimia nervosa will complete two weeks of EMA examining real-time affect changes in relation to the anticipation of binge eating and purging. These methods will facilitate rigorous assessment of the links between neurobiological (fMRI) and naturalistic (EMA) data in anticipatory reward processes. Findings from this investigation will inform the conceptualization and treatment of bulimia nervosa by identifying the role of reward anticipation in symptom maintenance, providing a crucial framework for targeting these anticipatory processes in existing and novel interventions.

Exploring Neural Mechanisms Related to Cognitive Control, Reward, and Affect in Eating Disorders: A Narrative Review of FMRI Studies

Studies using functional magnetic resonance imaging (fMRI) have contributed to our understanding of possible neural abnormalities among individuals with eating disorders. Many of these studies have focused on three domains: 1) cognitive control, 2) reward processing, and 3) affective processing. This review attempts to summarize the recent fMRI findings across these domains among the most well-characterized eating disorders: anorexia nervosa (AN), bulimia nervosa (BN), and binge eating disorder (BED). Though the literature is a bit murky, a few major themes have emerged. Cognitive control systems are affected among individuals across eating disorder diagnoses, but effects seem least pronounced in AN. Specifically, individuals with all eating disorders appear to show decreased prefrontal activation during cognitive control, but there is less evidence in AN linking decreased prefrontal activation with behavior. There is some evidence that the reinforcing value of food is reduced in AN, but individuals with BN and BED show hyperactivation to rewarding food-related stimuli, suggesting the reinforcing value of food may be enhanced. However, more complex reward processing paradigms show that individuals with BN and BED exhibit hypoactivation to reward anticipation and provide mixed results with regards to reward receipt. There are fewer neuroimaging findings related to affective processing, yet behavioral findings suggest affective processing is important in understanding eating disorders. Though the extant literature is complicated, these studies represent a foundation from which to build and provide insight into potential neurobiological mechanisms that may contribute to the pathophysiology of eating disorders.

Food Folio by Columbia Center for Eating Disorders: A Freely Available Food Image Database

Food images are useful stimuli for the study of cognitive processes as well as eating behavior. To enhance rigor and reproducibility in task-based research, it is advantageous to have stimulus sets that are publicly available and well characterized. Food Folio by Columbia Center for Eating Disorders is a publicly available set of 138 images of Western food items. The set was developed for the study of eating disorders, particularly for use in tasks that capture eating behavior characteristic of these illnesses. It contains foods that are typically eaten, as well as those typically avoided, by individuals with eating disorders. Each image has now been rated across 17 different attributes by a large general United States population sample via Amazon's Mechanical Turk (n = 1054). Ratings included subjective attributes (e.g., tastiness, healthiness, and favorable texture) as well as estimates of nutrient content (e.g., fat and carbohydrate). Each participant rated a subset of stimulus set food items (46 foods) on all 17 dimensions. Additional description of the image set is provided in terms of physical image information and accurate nutritional information. Correlations between subjective ratings were calculated and an exploratory factor analysis and exploratory cluster analysis completed. Outcomes of the factor analysis suggested foods may be described along three latent factors of healthiness, tastiness, and umami taste; the cluster analysis highlighted five distinct clusters of foods varying on these same dimensions. Descriptive outcomes indicated that the stimulus set includes a range of foods that vary along multiple dimensions and thus is likely to be useful in addressing various research questions surrounding eating behavior and cognition in healthy populations, as well as in those with eating disorders. The provision of comprehensive descriptive information allows for stimulus selection that is optimized for a given research question and promotes strong inference.

A comparison of food-based decision-making between restricting and binge-eating/purging subtypes of anorexia nervosa

OBJECTIVE

By definition, restricting (ANR) and binge-eating/purging (ANBP) subtypes of anorexia nervosa (AN) differ in some manifestations of maladaptive eating behavior. This study aimed to determine whether the groups differ in the choices they make about what to eat, and whether there are differences in valuation related to food choice, using an experimental paradigm.

METHOD

Inpatients with ANR (n = 40) and ANBP (n = 46) participated in a Food Choice Task. During the task, participants rated 76 food images for healthiness and tastiness, and choice preferences. Groups were compared in percent selection of high-fat and low-fat foods, value ratings of foods, and engagement of self-control in food choice.

RESULTS

There were no differences between AN subtypes in healthiness or tastiness ratings, or in tendency to limit choice of high-fat foods. There was no difference between the groups in measures of self-control in food choice.

DISCUSSION

Individuals with ANR and ANBP similarly manifest reduced choices of high-fat foods, with similar tendencies to undervalue the tastiness of high-fat foods. These results suggest that while individuals with ANR and ANBP differ across a range of clinical characteristics, the decision-making process associated with the maladaptive restriction of high-fat foods characteristic of AN is shared by both subtypes.