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Conceptualizing the role of disgust in avoidant/restrictive food intake disorder: Implications for the etiology and treatment of selective eating

Jessie E. Menzel PhD | Erin E. Reilly PhD | Tana J. Luo PhD | Walter H. Kaye MD

Department of Psychiatry, University of

California San Diego, San Diego,

California, USA

Correspondence

Jessie E. Menzel, University of California, San

Diego Eating Disorders Center for Treatment

and Research, 4510 Executive Drive, Suite

3315, San Diego, CA, 92121.

Email: [email protected]

Funding information

Hilda and Preston Davis Foundation

Abstract Selective eating is a common presenting problem in Avoidant/Restrictive Food Intake Disorder

(ARFID). Understanding the etiology of selective eating will lead to the creation of more effective

treatments for this problem. Recent reports have linked disgust sensitivity to picky eating, and the

field has yet to conceptualize the role that disgust might play in ARFID. Disgust has long been

tied to formation of taste aversions and is considered at its core to be a food-related emotion. A

brief review of the literature on disgust reveals that disgust has a unique psychophysiological

profile compared to other emotions, like anxiety, and that disgust is resistant to extinction pro-

cedures. If disgust is implicated in the etiology of selective eating, its presence would have a sig-

nificant impact on treatment approaches. This article provides an overview of the research on

disgust and eating, a clinical example of the treatment challenges that disgust may pose, and an

overview of the unique clinical features of disgust as they apply to psychopathology. We pose

several research questions related to disgust and selective eating and discuss initial hypotheses

for pursing this line of inquiry. Finally, we discuss the possible implications of this line of

research for treatment.

KEYWORDS

avoidant/restrictive food intake disorder, disgust, evaluative conditioning, feeding and eating

disorders, selective eating, treatment

1 | INTRODUCTION

Selective eating is a predominant symptom reported in some presen-

tations of Avoidant/Restrictive Food Intake Disorder (ARFID; Cooney,

Liberman, Guimond, & Katzman, 2018). Individuals with selective eat-

ing endorse sensitivity to tastes, textures, and other sensory qualities

of food, can be extremely limited in their dietary variety, and often

endorse anxiety related to trying novel foods (food neophobia). Selec-

tive eating is a commonly reported phenomenon in childhood and in

developmental disorders and has recently been linked to psychosocial

impairment and development of future psychiatric disorders (Zucker

et al., 2015). Researchers and clinicians agree that selective eating

exists along a spectrum from mild to severe and that moderate to

severe presentations, such as those that characterize a subset of

patients with ARFID, warrant intervention (Zucker et al., 2015). To

date, rigorous research on treatments for selective eating is lacking;

better characterizing the etiology of selective eating represents a

critical next step in ameliorating the suffering and functional impair-

ment linked with this behavior.

Current work in this area has focused on the association between

selective eating and sensory sensitivity (e.g., Naish & Harris, 2012;

Zucker et al., 2015). However, a number of recent studies have shown

a strong correlation between disgust sensitivity and selective eating,

food neophobia, and food-related textural aversions (Egolf, Siegrist, &

Hartmann, 2018; Hartmann & Siegrist, 2018; Kauer, Pelchat, Rozin, &

Zickgraf, 2015). These studies have shown that disgust sensitivity is

positively correlated with picky eating and textural aversions in a cross

sectional sample of healthy adults (Egolf et al., 2018; Kauer et al.,

2015). Experimental studies have demonstrated the role of disgust in

the development of conditioned food aversions in animals

(e.g., Garcia, Kimeldorf, & Kelling, 1955), that the number of previous

“disgust events” influences the development of neophobia

(e.g., Miller & Holzman, 1981), and that disgust-induced taste aver-

sions can be replicated in humans (e.g., Arwas, Rolnick, & Lubow,

Received: 31 July 2018 Revised: 5 December 2018 Accepted: 7 December 2018

DOI: 10.1002/eat.23006

462 © 2019 Wiley Periodicals, Inc. wileyonlinelibrary.com/journal/eat Int J Eat Disord. 2019;52:462–465.

1989). Disgust has been considered in etiological models of anorexia

nervosa (Hildebrandt et al., 2015) and food rejection in children

(Fallon, Rozin, & Pliner, 1984) but not yet in the context selective eat-

ing in ARFID. We propose that the role of disgust sensitivity in the

development of selective eating warrants explicit and thorough study,

particularly due to the implications it may have for treatment.

2 | CASE EXAMPLE

P was a 9 y/o, typically developing male when he presented to a pedi-

atric, intensive outpatient treatment program for poor growth, poor

appetite, and picky eating. At the time he presented for treatment, P

had not gained weight in the past 6 months and his BMI percentiles

had steadily decreased since age 5. Nonetheless, review of growth

charts indicated P was 90% of his expected body weight. He had been

a picky eater since early childhood and consumed only 10 foods with

regularity. Food items were specific to brand and texture, his range of

preferred foods narrowed over time, and he had dropped previously

preferred foods. Parents reported frequent gagging when eating, par-

ticularly when trying new foods. P's family described him as a perfec-

tionistic and rigid child, but diagnostic interviews and parent-report

assessments indicated no other comorbid psychopathology. Treat-

ment followed a family-based model and emphasized initial weight

restoration on preferred foods prior to employing graduated exposure

with reinforcement and escape contingencies to add new foods. The

patient and parents made a list of foods to add to the patient's diet,

and exposures were patient-led with respect to food choice. Food

exposures were called “food experiments” and patient was encour-

aged to be a “food scientist,” channeling openness and curiosity when

trying new foods.

The course of each food exposure trial was similar. Initial food

exposures consisted of pea-sized amounts of new foods. The patient

exhibited significant behavioral avoidance (turning in chair, wiggling,

and dropping spoon) and would take between 1 and 30 min to

attempt the new food. Grimacing, gagging, or spitting out the food

was a common response. Behavioral avoidance and disliking of new

foods increased with subsequent trials. Patient's hedonic response to

food was immediately evident, and black and white in nature; he

either liked the food or “hated” it. The patient became hesitant to

report any degree of food preference due to anticipation of repeated

exposure and increased demand; for example, if the patient attempted

a food but did not have an observable disgust response, he still

reported “hating” the food. Our clinicians hypothesized that the

patient's strong disgust response to early food trials, as evidenced by

facial expression and gagging, resulted in an aversive, conditioned

response to trying new foods that generalized to future food trials.

3 | DISGUST, ANXIETY, AND TREATMENT

The case of P is an illustrative case of food selectivity treated at the

UCSD Eating Disorders Center and highlights the potential challenge

that disgust sensitivity may pose in the treatment of selective eating.

Disgust is an adaptive system that serves to protect against

contamination, infection, and disease and at its core, is considered a

food-related emotion (Rozin & Fallon, 1987). An emerging literature

implicates disgust in anxious psychopathologies, particularly

contamination-related obsessive–compulsive disorder, blood-injury-

injection phobia, and spider phobia (see Olatunji, Cisler, McKay, &

Phillips, 2010, for a review). While disgust and fear both motivate

avoidance behaviors, each emotion is characterized by a distinct pro-

file of stimulus triggers, physiological responses, facial expressions,

behaviors, and cognitive appraisals. Disgust-specific stimuli include

odors (e.g., rotting and decay), tactile cues (e.g., sliminess, lumps and

bumps), and visual cues (e.g., mold, discoloration). Disgust responses

are characterized by parasympathetic activation, distinct facial mus-

cle activation, contamination appraisals, and oral rejection. In con-

trast, fear responses are associated with increased sympathetic

activity, appraisals of danger or harm, and behavioral inhibition

(Cisler, Olatunji, & Lohr, 2009).

Based on these discrepant profiles, it is logical to predict that dis-

gust and anxiety may not respond similarly to intervention. Indeed,

research has recently turned to a consideration of disgust in exposure

treatment efficacy. Initial investigations indicate that, compared to

fear, disgust exhibits slower rates of habituation and a resistance to

extinction (e.g., Olatunji, Wolitzky-Taylor, Willems, Lohr, & Armstrong,

2009; Smitz, Telch, & Randall, 2002). Furthermore, experimentally

conditioned disgust associations have been shown to be unresponsive

to extinction produces (Olatunji, Forsyth, & Cherian, 2007). While

experience with a disgusting stimulus may be associated with second-

ary anxiety, these differential responses to exposure and extinction

procedures strengthen the assertion that disgust and anxiety are dis-

tinct emotional constructs.

The reduced susceptibility of disgust to extinction may be par-

tially accounted for by evaluative conditioning processes. Evaluative

conditioning refers to the acquisition of likes and dislikes via the pair-

ing of stimuli with other positively or negatively valenced stimuli.

Importantly, evaluative learning appears to be more resistant to

extinction than expectancy learning (Vansteenwegen, Frankcken,

Vervliet, De Clercq, & Eelen, 2006). That is, learned dislike may persist,

even when a given stimulus is no longer feared or associated with

aversive outcomes. Moreover, recent studies using both self-report

and behavioral indicators of disgust (e.g., visual avoidance) provide

evidence that both disgust-specific expectancy learning and evalua-

tive learning are resistant to extinction (Mason & Richardson, 2012;

Olatunji et al., 2007). The resistance of disgust to extinction implies

that exposure treatments may have limited efficacy in targeting

disgust-motivated avoidance. This theory would have obvious implica-

tions for the treatment of selective eating if disgust sensitivity indeed

plays a role in its etiology and would influence any approaches that

use graduated exposure to expand food variety.

4 | CONSIDERING THE ROLE OF DISGUST IN SELECTIVE EATING IN ARFID

Given the clinical observation of disgust in selective eating and the

significant impact it could have on treatment efficacy, we propose

that our field more explicitly consider the role of disgust sensitivity in

MENZEL ET AL. 463

selective eating and food avoidance. Future research needs to answer

several questions to illuminate the role of disgust, if any, in this variant

of ARFID. Primarily, in cross sectional samples, is there an association

between disgust sensitivity and selective eating in individuals present-

ing with ARFID? If so, is this association consistent across all selective

eaters, in specific subgroups of selective eaters, or just at certain

levels of selective eating severity? Furthermore, does this association

exist only with selective eating or also with other restrictive eating

patterns observed in ARFID (e.g., food-related phobias)? Second, how

does disgust sensitivity relate to or overlap with textural sensitivity,

food neophobia, and picky eating? Cross-sectional research could help

determine if disgust sensitivity accounts for overlap between these

variables. However, experimental paradigms using psychophysiologi-

cal measures may better aid in distinguishing between these con-

structs in the context of food exposure. These methods, along with

neuroimaging research, would also be useful in determining the rela-

tionship between disgust and hedonic response to food. For example,

do individuals with higher disgust sensitivity find food less enjoyable

and could disgust sensitivity potentially moderate changes in liking for

food over the course of treatment? Third, the field should explicitly

test whether individuals with the selective-eating variant of ARFID

endorse higher disgust sensitivity than (1) healthy control subjects, as

well as (2) those individuals who endorse generalized food selectivity

but do meet criteria for a full-threshold ARFID diagnosis. Fourth,

given that the majority of past work has focused on cross-sectional

associations between disgust sensitivity and picky eating, it will be

important to evaluate—through both experimental and longitudinal

designs—prospective relations between a state disgust experience,

general and food-specific disgust sensitivity, sensory sensitivity, and

the onset of selective eating. It could be possible that sensory sensi-

tivity is a vulnerability factor for selective eating and that disgust

emerges after repeated encounters with food and is thus more central

in maintaining food rejection behaviors. On the other hand, disgust

sensitivity may be a unique predictor of the onset of selective eating.

In order to answer these questions adequately given the developmen-

tal spectrum of ARFID, future studies should consider inclusions of

very young populations, including infants. Finally, we feel it is impor-

tant that future researchers consider using multimodal methods for

assessing disgust, including self-report measures (e.g., the Food Dis-

gust Scale; Hartmann & Siegrist, 2018), behavioral avoidance para-

digms, facial expression assessment, and physiological response.

4.1 | Treatment implications for disgust and ARFID

Should future research indicate disgust sensitivity is linked with selec-

tive eating in ARFID, those findings would have significant implica-

tions for treatment. While no treatments for selective eating have

been systematically tested on a large scale with adequate controls,

interventions from single case designs in medically compromised or

developmentally disabled populations typically utilize some form of

behavioral approach with graduated exposure and contingency man-

agement as the primary method for introducing new foods and

expanding dietary variety (Sharp, Jaquess, Morton, & Herzinger,

2010). Given the previously stated complications of using traditional

exposure procedures to target disgust, clinicians will need to adapt

exposure treatments or investigate novel treatments to target disgust

effectively. Previous authors have proposed several methods through

which clinicians delivering behavioral treatments may account for dis-

gust (Mason & Richardson, 2012). For example, conceptual decon-

struction techniques (Rozin & Fallon, 1987) or secondary appraisals of

one's ability to cope with disgust (Teachman, 2006) may be helpful.

Researchers and clinicians may also consider counter-conditioning

methods, wherein disgust-eliciting stimuli are paired with rewarding

stimuli or with safety-signals (Bosman, Borg, & de Jong, 2016; Engel-

hard, Leer, Lange, & Olatunji, 2014). Pilot testing techniques that

focus on targeting evaluative associations may be a fruitful area to

pursue. Finally, these techniques would have obvious applications

beyond treatment of selective eating and may be useful in tailoring

treatments for ARFID patients with food avoidance motivated by

fear-based associations, such as fear of vomiting or contamination.

5 | DISCUSSION

Emerging work in the field of eating disorders indicates that a signifi-

cant number of ARFID cases are characterized by impairing selective

eating behaviors. While the broader role of emotion in functional food

avoidance warrants due consideration, we propose that future

research explicitly consider the role of disgust and disgust sensitivity

in accounting for the onset and maintenance of selective eating in the

context of ARFID. Exploring the function of disgust among individuals

with selective eating could aid in delineating more specific etiological

models as well as formulation of more tailored, effective treatment

strategies.

ACKNOWLEDGMENTS

Author E.E.R. receives funding through the Hilda and Preston Davis

Foundation.

ORCID

Jessie E. Menzel https://orcid.org/0000-0003-4294-2680

Erin E. Reilly https://orcid.org/0000-0001-9269-0747

Walter H. Kaye https://orcid.org/0000-0002-4478-4906

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How to cite this article: Menzel JE, Reilly EE, Luo TJ,

Kaye WH. Conceptualizing the role of disgust in avoidant/

restrictive food intake disorder: Implications for the etiology

and treatment of selective eating. Int J Eat Disord. 2019;52:

462–465. https://doi.org/10.1002/eat.23006

MENZEL ET AL. 465

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