Internal states and interoception along a spectrum of eating disorder symptomology

Dietary intake of adults with eating disorders: A systematic review and meta-analysis

Studies have confirmed the link between altered dietary intake and eating disorders (EDs), although no systematic assessment of this research exists. Rigorous synthesis of dietary intake in anorexia nervosa (AN), bulimia nervosa (BN), binge-eating disorder (BED), and similar EDs is needed to explore similarities and differences. In accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement, we conducted a systematic review and quantitative synthesis of studies of dietary intake. Searches of three electronic databases resulted in thirty-nine included studies. Meta-analyses of subsets of these studies were undertaken to summarise macronutrient intake across AN, BN, and BED. Study quality was assessed using the American Academy of Nutrition and Dietetics Quality Criteria Checklist, with ratings either Positive (k = 27) or Neutral (k = 12). Adults with AN had low energy intake and those with BED reported elevated macronutrient intake. Individuals with BN reported wide variation in energy intake, including some of the highest estimates. Individuals with AN were likely to under-consume key micronutrients, with sodium potentially over-consumed in BN and BED. Vitamin D was under-consumed across all disorders. This meta-analysis highlights important diagnostic differences and synthesises dietary intake in EDs, with particular relevance to risk assessment and treatment.

Perceptual Dysfunction in Eating Disorders

Eating disorders (EDs) are characterized by abnormal responses to food and weight-related stimuli and are associated with significant distress, impairment, and poor outcomes. Because many of the cardinal symptoms of EDs involve disturbances in perception of one's body or abnormal affective or cognitive reactions to food intake and how that affects one's size, there has been longstanding interest in characterizing alterations in sensory perception among differing ED diagnostic groups. Within the current review, we aimed to critically assess the existing research on exteroceptive and interoceptive perception and how sensory perception may influence ED behavior. Overall, existing research is most consistent regarding alterations in taste, visual, tactile, and gastric-specific interoceptive processing in EDs, with emerging work indicating elevated respiratory and cardiovascular sensitivity. However, this work is far from conclusive, with most studies unable to speak to the precise etiology of observed perceptual differences in these domains and disentangle these effects from affective and cognitive processes observed within EDs. Further, existing knowledge regarding perceptual disturbances in EDs is limited by heterogeneity in methodology, lack of multimodal assessment protocols, and inconsistent attention to different ED diagnoses. We propose several new avenues for improving neurobiology-informed research on sensory processing to generate actionable knowledge that can inform the development of innovative interventions for these serious disorders.

Is intuitive eating a privileged approach? Cross-sectional and longitudinal associations between food insecurity and intuitive eating

OBJECTIVE

To examine: (1) cross-sectional and longitudinal associations between measures of food insecurity (FI; household status and youth-reported) and intuitive eating (IE) from adolescence to emerging adulthood; and (2) the association between FI persistence and IE in emerging adulthood.

DESIGN

Longitudinal population-based study. Young people reported IE and FI (two items from the US Household Food Security Module) in adolescence and emerging adulthood. Parents provided data on household FI via the six-item US Household Food Security Module in adolescence.

SETTING

Adolescents (Mage = 14·3 ± 2 years) and their parents, recruited from Minneapolis/St. Paul public schools in 2009-2010 and again in 2017-2018 as emerging adults (Mage = 22·1 ± 2 years).

PARTICIPANTS

The analytic sample (n 1372; 53·1 % female, 46·9 % male) was diverse across race/ethnicity (19·8 % Asian, 28·5 % Black, 16·6 % Latinx, 14·7 % Multiracial/Other and 19·9 % White) and socio-economic status (58·6 % low/lower middle, 16·8 % middle and 21·0 % upper middle/high).

RESULTS

In cross-sectional analyses, youth-reported FI was associated with lower IE during adolescence (P = 0·02) and emerging adulthood (P < 0·001). Longitudinally, household FI, but not adolescent experience of FI, was associated with lower IE in emerging adulthood (P = 0·01). Those who remained food-insecure (P = 0·05) or became food-insecure (P = 0·02) had lower IE in emerging adulthood than those remaining food-secure. All effect sizes were small.

CONCLUSIONS

Results suggest FI may exert immediate and potentially lasting impacts on IE. As evidence suggests IE is an adaptive approach conferring benefits beyond eating, it would be valuable for interventions to address social and structural barriers that could impede IE.

Examination of the two-step water load test as a measure of gastric interoception and associations with eating and weight/shape concerns in a nonclinical sample

OBJECTIVE

The current study extended research examining the validity of the two-step Water Load Test (WLT-II), an objective, laboratory-based measure of gastric interoception, by investigating the validity of the WLT-II in a nonclinical sample and testing its contribution to the prediction of eating and weight/shape concerns.

METHODS

Participants (n = 129, 73.6% cisgender female, M = 20.13 years old) completed the WLT-II Questionnaire and two-step WLT-II, as well as self-report measures of eating and weight/shape concerns (Eating Disorder Examination Questionnaire; EDE-Q) and interoception (Multidimensional Assessment of Interoceptive Awareness-2; Intuitive Eating Scale-2 Reliance on Hunger and Satiety), in the lab at a large southeastern university. Data analysis included repeated measures ANOVA, correlations, and a series of hierarchical linear regressions.

RESULTS

Participants reported considerably more discomfort after the "maximum fullness" trial compared to the "satiation" trial. The WLT-II's objective measure of gastric interoception (sat_%) was not significantly correlated with the self-report measures of interoception and did not predict EDE-Q Dietary Restraint, Eating Shame, or Weight/Shape Concerns. Unexpectedly, greater gastric sensitivity was associated with less EDE-Q Preoccupation/Restriction. Exploratory analyses suggested a possible nonlinear association.

DISCUSSION

These results support the validity of the WLT-II in its ability to create, measure, and distinguish between the states of satiation and maximum fullness. However, results also suggest additional work is needed to better understand what the WLT-II's sat_% measure is capturing, as well as investigate potential nonlinear associations of the WLT-II with disordered eating.

PUBLIC SIGNIFICANCE

Interoception, or the processing of internal body signals, shows important links to disordered eating. Despite the clear relevance of gastric interoception to disordered eating-such as the ability to detect satiety signals-existing research has relied on general, self-report measures of interoception. This study examined the utility of a laboratory-based measure of gastric interoception. Results suggested mixed support for its validity and utility for predicting eating and weight/shape concerns in a nonclinical population.

A lived experience response to the proposed diagnosis of terminal anorexia nervosa: learning from iatrogenic harm, ambivalence and enduring hope

The ethical approach to treatment non-response and treatment refusal in severe-enduring anorexia nervosa (SE-AN) is the source of significant ethical debate, particularly given the risk of death by suicide or medical complications. A recent article proposed criteria to define when anorexia nervosa (AN) can be diagnosed as 'terminal' in order to facilitate euthanasia or physician-assisted suicide (EAS), otherwise known as medical assistance in dying, for individuals who wish to be relieved of suffering and accept treatment as 'futile'. This author utilises their personal lived experience to reflect on the issues raised, including: treatment refusal, iatrogenic harm, suicidality and desire to end suffering, impact of diagnosis/prognosis, schemas, alexithymia, countertransference, ambivalence, and holding on to hope. Within debates as critical as the bioethics of involuntary treatment, end-of-life and EAS in eating disorders, it is crucial that the literature includes multiple cases and perspectives of individuals with SE-AN that represent a wide range of experiences and explores the complexity of enduring AN illness, complex beliefs, communication patterns and relational dynamics that occur in SE-AN.

Longitudinal relationships between specific domains of interoception and muscle dysmorphia symptoms

Muscle dysmorphia (MD) is a subtype of body dysmorphic disorder (BDD); few risk factors for MD symptom development have been identified. One potential risk factor may be decreased interoceptive sensibility (impaired ability to recognize bodily sensations), which is present across a range of mental disorders. Notably, impaired interoceptive awareness is elevated in populations at-risk for MD. Furthermore, interoception is associated with MD symptoms, and theoretically, interoceptive dysfunction may facilitate engagement in MD symptoms. However, longitudinal research on interoception and MD is scarce, and specific MD symptoms implicated in these relationships are unknown. This study examined longitudinal relationships between specific domains of interoceptive sensibility and MD symptoms. Participants were 255 (26.7% Male; 72.1% Female; 1.2% Non-binary) undergraduates who completed two self-report surveys separated by four weeks. A path model was specified in which seven forms of interoception predicted five MD symptoms. Results suggested that interoceptive sensibility characterized by difficulties attending to bodily sensations and viewing these sensations as distracting predicted MD symptoms like muscle checking, positive attitudes towards using muscle-building substances, and compulsive exercise. Specific forms of impaired interoceptive sensibility may represent a risk factor for MD symptoms. If clinicians can increase the interoceptive abilities of their clients at risk for MD, this may prevent the development of MD symptoms.

Intuitive Eating Scale-2: psychometric properties and clinical norms among individuals seeking treatment for an eating disorder in private practice

PURPOSE

Intuitive Eating (IE) is an approach to eating designed to facilitate a positive relationship with food. Its use in clinical settings and in the community is rapidly growing in popularity. The Intuitive Eating Scale 2 (IES-2) is a widely used measure that indexes intuitive eating motivations and behaviour, however evidence of its validity in populations with clinical eating disorders remains scarce. The objective of the proposed study was thus to evaluate the factor structure of the IES-2 in a large sample of individuals seeking treatment for eating disorders in private practice.

METHODS

Data collected from 569 women and men aged 12-68 years seeking treatment for an eating disorder in one of eight specialist private outpatient eating disorder clinics were examined using confirmatory factor analysis (CFA). Relationships between IES-2 scores and measures of psychopathology were also examined.

RESULTS

Results were relatively consistent with the purported four-factor structure of the IES-2. The measure displayed strong construct validity and good internal consistency. Scores on the IES-2 were inversely associated with scores of depression, anxiety, and disordered eating, providing evidence for divergent validity of the measure. Clinical norms are provided for anorexia nervosa (AN) spectrum disorders and bulimia nervosa (BN) spectrum disorders, as well as for the clinical sample as a whole.

CONCLUSION

Findings suggest that the IES-2 may be an appropriate measure for evaluating behaviours relating to IE in community outpatient eating disorder settings, and provide further evidence for the association between IE and positive health outcomes.

LEVEL OF EVIDENCE

III, evidence obtained from well-designed cohort or case-control analytic studies.

General versus hunger/satiety-specific interoceptive sensibility in predicting disordered eating

Dysfunctional interoceptive processing of hunger and satiety cues is particularly relevant to disordered eating behaviors. However, researchers often rely on general measures of interoceptive sensibility (IS¹; self-reported experience of internal bodily cues) which conflate interoceptive processes across biological systems (e.g., gastric, cardiac) when assessing the role of interoception in disordered eating. Participants (N = 213; 50% female, age M = 20.77 years) were recruited from a large southeastern university for this online study and completed the Intuitive Eating Scale-2 (hunger/satiety-specific), the Multidimensional Assessment of Interoceptive Awareness-2 (general), and the Eating Disorder Inventory Interoceptive Awareness Subscale (general) as measures of IS. The Eating Pathology Symptoms Inventory was used to assess disordered eating attitudes and behaviors. Controlling for sex and body mass index, hunger/satiety-specific IS was associated with binge eating, purging, and cognitive restraint over and above general IS measures and emerged as the dominant predictor of each. Hunger/satiety-specific IS did not predict restricting behavior. Dysfunctional processing of hunger and satiety cues may be a particularly important risk factor to target in screenings and interventions for disordered eating. Findings highlight the importance of careful selection of IS measures in research and targeting hunger/satiety-specific IS in clinical interventions for disordered eating.